[House Hearing, 114 Congress]
[From the U.S. Government Publishing Office]
SCIENCE OF ZIKA: THE DNA OF AN EPIDEMIC
=======================================================================
HEARING
BEFORE THE
COMMITTEE ON SCIENCE, SPACE, AND TECHNOLOGY
HOUSE OF REPRESENTATIVES
ONE HUNDRED FOURTEENTH CONGRESS
SECOND SESSION
__________
May 25, 2016
__________
Serial No. 114-79
__________
Printed for the use of the Committee on Science, Space, and Technology
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COMMITTEE ON SCIENCE, SPACE, AND TECHNOLOGY
HON. LAMAR S. SMITH, Texas, Chair
FRANK D. LUCAS, Oklahoma EDDIE BERNICE JOHNSON, Texas
F. JAMES SENSENBRENNER, JR., ZOE LOFGREN, California
Wisconsin DANIEL LIPINSKI, Illinois
DANA ROHRABACHER, California DONNA F. EDWARDS, Maryland
RANDY NEUGEBAUER, Texas SUZANNE BONAMICI, Oregon
MICHAEL T. McCAUL, Texas ERIC SWALWELL, California
MO BROOKS, Alabama ALAN GRAYSON, Florida
RANDY HULTGREN, Illinois AMI BERA, California
BILL POSEY, Florida ELIZABETH H. ESTY, Connecticut
THOMAS MASSIE, Kentucky MARC A. VEASEY, Texas
JIM BRIDENSTINE, Oklahoma KATHERINE M. CLARK, Massachusetts
RANDY K. WEBER, Texas DON S. BEYER, JR., Virginia
JOHN R. MOOLENAAR, Michigan ED PERLMUTTER, Colorado
STEVE KNIGHT, California PAUL TONKO, New York
BRIAN BABIN, Texas MARK TAKANO, California
BRUCE WESTERMAN, Arkansas BILL FOSTER, Illinois
BARBARA COMSTOCK, Virginia
GARY PALMER, Alabama
BARRY LOUDERMILK, Georgia
RALPH LEE ABRAHAM, Louisiana
DARIN LaHOOD, Illinois
C O N T E N T S
May 25, 2016
Page
Witness List..................................................... 2
Hearing Charter.................................................. 3
Opening Statements
Statement by Representative Lamar S. Smith, Chairman, Committee
on Science, Space, and Technology, U.S. House of
Representatives................................................ 4
Written Statement............................................ 6
Statement by Representative Eddie Bernice Johnson, Ranking
Member, Committee on Science, Space, and Technology, U.S. House
of Representatives............................................. 8
Written Statement............................................ 10
Witnesses:
Dr. Kacey Ernst, Associate Professor, Department of Epidemiology
and Biostatistics, University of Arizona
Oral Statement............................................... 14
Written Statement............................................ 17
Dr. Daniel Neafsey, Associate Director, Genomic Center for
Infectious Disease, Broad Institute of MIT and Harvard
Oral Statement............................................... 30
Written Statement............................................ 32
Dr. Steven Presley, Professor, Department of Environmental
Toxicology, Texas Tech University
Oral Statement............................................... 38
Written Statement............................................ 40
Mr. Hadyn Parry, Chief Executive Officer, Oxitec
Oral Statement............................................... 49
Written Statement............................................ 51
Discussion....................................................... 64
Appendix I: Answers to Post-Hearing Questions
Dr. Kacey Ernst, Associate Professor, Department of Epidemiology
and Biostatistics, University of Arizona....................... 88
Dr. Daniel Neafsey, Associate Director, Genomic Center for
Infectious Disease, Broad Institute of MIT and Harvard......... 100
Dr. Steven Presley, Professor, Department of Environmental
Toxicology, Texas Tech University.............................. 102
Mr. Hadyn Parry, Chief Executive Officer, Oxitec................. 105
SCIENCE OF ZIKA: THE DNA OF AN EPIDEMIC
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WEDNESDAY, MAY 25, 2016
House of Representatives,
Committee on Science, Space, and Technology,
Washington, D.C.
The Committee met, pursuant to other business, at 10:25
a.m., in Room 2318 of the Rayburn House Office Building, Hon.
Lamar Smith [Chairman of the Committee] presiding.
[GRAPHICS NOT AVAILABLE IN TIFF FORMAT]
Chairman Smith. The Committee on Science, Space, and
Technology will again come to order.
Without objection, the Chair is authorized to declare
recesses of the Committee at any time.
Good morning, and welcome to today's hearing titled ``The
Science of Zika: the DNA of an Epidemic.'' Let me recognize
myself for five minutes for an opening statement.
For more than a century, humans have been at war with the
mosquito. In 1901, a U.S. Army physician named Walter Reed led
a team in Cuba studying diseases that proved yellow fever was
transmitted by mosquitoes.
Since that discovery, governments, scientists, and
individuals have pursued ways to prevent and control deadly
mosquito-borne outbreaks. From yellow fever, to dengue fever,
to Nile virus, humans are constantly under siege from new
mosquito-transmitted diseases.
Today, we will examine the state of science in the most
recent battle in the war against mosquito-borne disease: the
Zika virus.
While for most people Zika causes only mild illness, the
Centers for Disease Control and Prevention have found that
there is a link between Zika infection during a woman's
pregnancy and severe birth defects. For some adults there could
also be serious neurological impacts.
Summer is coming and so are the mosquitoes that spread the
Zika virus. The Gulf Coast of Texas, among other places, has
been called ground zero for this type of mosquito that carries
Zika.
Zika infections have spread to over 80 countries and
territories in Latin America and the Caribbean. We have seen
local transmission of the virus in U.S. territories. In
addition, over 500 people in the United States mainland have
acquired the Zika virus while traveling out of the country.
Over 300 of these are pregnant women.
These dangers raise serious questions about the
Administration's handling of travel alerts. The CDC has issued
level two alerts for 49 countries and territories, which advise
travelers only to ``practice enhanced precautions.'' They have
not issued any level three warnings to ``avoid nonessential
travel,'' as they did during the Ebola epidemic in West Africa.
The World Health Organization in February declared Zika a
Public Health Emergency of International Concern. Such
declaration is reserved for a situation that is ``serious,
unusual or unexpected, carries implications for public health
beyond the affected state's national border, and may require
immediate international action.''
Why has the Administration not raised the travel alert
level for countries with the highest number of Zika infections,
such as Brazil and Colombia? Is the Administration so worried
about attendance at the Olympics in Brazil this summer that
they're willing to endanger American lives by not providing
better warnings? At the least, pregnant women should be told to
avoid nonessential travel to Brazil and Colombia. Anything less
is putting political correctness ahead of the well-being of
American women.
Today I hope that we can gather additional scientific
information on Zika and the mosquito that spreads it. I also
look forward to hearing about research on the best methods for
controlling the spread of the Zika virus.
[The prepared statement of Chairman Smith follows:]
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Chairman Smith. That concludes my opening statement, and
the gentlewoman from Texas, Ms. Johnson, the Ranking Member, is
recognized for her opening statement.
Ms. Johnson. Thank you very much, Mr. Chairman, for holding
this hearing.
This morning we are talking about the Zika virus, something
that has been in the news a lot lately and that we have been
debating on the House Floor.
The most common way that someone becomes infected with the
Zika virus is by a mosquito bite. The symptoms of the virus may
include fever, rash, joint pain, and red eyes. These symptoms
are typically mild, and many people who get infected with the
Zika virus have no symptoms or do not seek medical treatment.
Although the Zika virus was first identified in the late
1940s, there were no major outbreaks of the Zika virus until
2007. Since then, the Zika virus has been reported in almost 70
countries and territories, including the major Zika outbreak
that is happening in Brazil, where more than a million cases
have been reported.
In the United States, local transmission of the Zika virus
has been reported in several U.S. territories. In particular,
Puerto Rico is suffering from a large Zika outbreak in which
more than 800 cases have been reported to date. In the
continental United States, the only Zika cases that have been
reported involve people who have traveled to places that have a
Zika outbreak. But the number of those cases is already more
than 500, and there is significant concern that the continental
United States will start seeing locally transmitted cases of
the Zika virus once we get further into the mosquito season.
Even though my home State of Texas only has 35 travel-
associated cases of the Zika virus so far, I have been hearing
from a lot of concerned constituents about the Zika virus and
the potential for a Zika outbreak in Texas this summer.
I would imagine that many of my colleagues on this
Committee have been hearing from concerned constituents as
well. I am pleased that we will have more information to pass
on to them after this hearing.
What is especially troubling about the Zika virus is that
it has been associated with several significant health
conditions, including birth defects in infants and neurological
conditions in adults. Most notably, the Zika virus has been
linked to microcephaly, a birth defect where the brain does not
develop during pregnancy or after birth. This condition results
in significant impairments for the baby and can result in
death. Brazil has seen thousands of these cases. In the United
States and territories, hundreds of pregnant women who have
been infected with the Zika virus are currently being
monitored. Unfortunately, last week the first case of
microcephaly was reported in Puerto Rico.
Additionally, the Zika virus has been associated with
Guillain-Barre syndrome, a disorder where the body's immune
system attacks part of the nervous system. People who have this
syndrome usually recover, but the syndrome can result in
permanent paralysis or death.
Understandably, people are very concerned about this virus
and want more information. That is why I am happy we are
holding this hearing to learn more about the science behind
this disease and to hear more about the key research questions.
For example, how is the virus transmitted from mother to fetus
and how is the risk to the fetus related to the timing of the
mother's infection? Does Zika cause Guillain-Barre syndrome and
if so, is there an intervention that can prevent this terrible
condition?
We also need to know where the vector mosquitoes live, the
incubation period of the virus in the mosquito, and whether the
infected female can transmit the virus to her eggs.
Finally, it is perplexing that the Zika virus was first
identified in the late 1940s, but we are only seeing major Zika
outbreaks now. What has changed in the last 70 years to make
conditions more suitable for the virus to be transmitted? I
imagine that the rapid increase in human travel has played a
large role, but I do wonder how much other factors like
insecticide resistance and climate change may be playing in the
spread of this disease.
All of these research questions need to be answered as we
plan effective mosquito control programs and prepare to invest
our resources. But traditional mosquito control programs will
not be enough.
I am looking forward to hearing from our expert witnesses
on how emerging technologies that use advanced genetics and
biologic technologies could help control the Zika virus.
It is also important to note that to support the necessary
research, surveillance, mosquito control, and drug and vaccine
development programs that will be needed to control this
disease, we must ensure that adequate funding is provided. I am
hopeful that Congress can come together to provide that
funding. Time is of the essence. And I'm thankful that the
experts are here.
And just before I yield back, Mr. Chairman, I want to take
a moment to recognize one of my staff, Kim Montgomery, who is
sitting beside me now. She's leaving soon to move to Vienna,
Austria. She has been an integral part of the staff. Her
passion and expertise will be greatly missed. I want to thank
you for your service and wish you luck in your new, exciting
chapter in Vienna.
Thank you, and I yield back, Mr. Chairman.
[The prepared statement of Ms. Johnson follows:]
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Chairman Smith. Thank you, Mrs. Johnson.
Let me introduce our witnesses, and our first witness today
is Dr. Kacey Ernst, Associate Professor, Department of
Epidemiology and Biostatistics at the University of Arizona.
Dr. Ernst joined the University of Arizona staff in 2008. Her
area of specialization is the intersection of environment,
humans, and mosquito vectors of disease. As an epidemiologist,
her role is to work with a highly interdisciplinary team of
scientists to integrate information from climatology,
entomology, medical anthropology, and ecology across multiple
institutions to develop an understanding of the emergence of
infectious diseases. Dr. Ernst received her master's in public
health and doctorate in epidemiology from the University of
Michigan.
We want to thank particularly Dr. Ernst today for being
here because in so doing she is missing her daughter Savannah's
graduation from the fifth grade and on to middle school. So
tell your daughter that we appreciate your good help in trying
to help the Federal Government, and I hope she'll excuse you
missing that graduation.
Our second witness today is Dr. Daniel Neafsey, Associate
Director, Genomic Center for Infectious Disease at the Broad
Institute of MIT and Harvard. In this role, Dr. Neafsey leads a
research group studying the DNA of mosquito vectors and the
pathogens they transmit. He has developed pioneering resources
and computational methodologies for genetic studies of
mosquitoes and mosquito-borne pathogens. Dr. Neafsey received
his B.A. from Loyola University in Chicago and his Ph.D. from
Harvard University.
Our next witness, Dr. Steven Presley, will be introduced by
the gentleman from Texas, Mr. Neugebauer.
Mr. Neugebauer. Well, thank you, Mr. Chairman.
Our third witness today is Dr. Steven Presley. He's a
Professor in the Department of Environmental Toxicology at
Texas Tech University. Dr. Presley's professional career has
focused upon vector-borne infectious diseases with an emphasis
on biological threat assessment and countermeasures to protect
the population from infectious diseases. He's published more
than 90 scientific and technical papers, co-edited two
textbooks, authored and co-authored 11 book chapters in the
fields of biological and chemical countermeasures and diseases
of wildlife. He served in the United States Navy in the Medical
Services Corps and he was an officer for more than 12 years
before joining the faculty at Texas Tech University in 2002. He
earned his bachelor of science in animal science from Texas
Tech University and master of science and doctorate of
philosophy in entomology from Oklahoma State. It's good to have
a fellow Red Rider, Dr. Steven Presley, with us today.
Chairman Smith. Thank you, Mr. Neugebauer.
Our last today is Mr. Hadyn Parry, Chief Executive Officer
of Oxitec, a U.K.-based company pioneering the use of genetic
engineering to control insects that spread disease and damage
crops. During his 15-year career at Zeneca Syngenta, he held
various positions including general manager of Zeneca Plant
Sciences. Mr. Parry also has served as the European Director
and Global Head of R&D for Advanta, one of the world's largest
seed companies. More recently, he was CEO of MNL
Pharmaceuticals, a company that was focused on pioneering a
novel approach to immunology. Mr. Parry received a bachelor of
arts in international history and politics from the University
of Leeds.
We welcome you all, and Dr. Ernst, we will begin with you.
TESTIMONY OF DR. KACEY ERNST,
ASSOCIATE PROFESSOR,
DEPARTMENT OF EPIDEMIOLOGY
AND BIOSTATISTICS,
UNIVERSITY OF ARIZONA
Dr. Ernest. Thank you. Thank you, Chairman Smith and
Ranking Member Johnson.
So today I want to give you a little bit of background on
the Aedes aegypti mosquito. This is the mosquito depicted here.
It is the primary vector of Zika virus. It's highly adaptable
and highly invasive. It's originally from sub-Saharan Africa
but has been widely dispersed across the globe through the
mobilization of people and goods.
Aedes aegypti is tightly linked to humans and their
activities. It prefers to feed on human blood, and lays its
eggs in manmade containers in and around homes. One of the
reasons why it's such a difficult mosquito to control is
because it can exploit even as much as one inch of water to go
through its entire immature lifecycle.
It's a day biter, which means that it primarily feeds in
the morning and in the afternoon, which means things like bed
nets are not as effective as protecting against the diseases
that it's transmitting.
Not only does this mosquito transmit Zika virus but it is
also a primary transmitter of yellow fever, dengue,
chikungunya, and one that you probably haven't heard of yet,
which is called Mayaro virus. Next slide, please.
[Slide.]
This is the CDC's recently updated maps of the estimated
distribution of Aedes aegypti and Aedes albopictus in the
United States. Aedes albopictus is a relative of Aedes aegypti,
which is also capable of transmitting Zika virus, but it can
withstand cooler temperatures and it is a more generalist
feeder. That means that it doesn't feed as preferentially on
humans as Aedes aegypti. Its role in the current outbreak is
not well understood at this time.
The ranges here are only estimates because many of the
jurisdictions in these areas do not have active surveillance
for Aedes species. Next slide, please.
[Slide.]
The predominant transmission cycle for Zika virus occurs
when a female Aedes aegypti mosquito bites an infected human.
The virus goes through a development stage in the mosquito of a
currently unknown time period, probably about a week is what we
estimate at this time, and that is dependent upon the
temperature. It would be faster if you have hotter
temperatures. This is called the extrinsic incubation period.
After that time period, the mosquito is capable of transmitting
the virus to the next person that it bites and then remains
capable of transmitting for the duration of her life, about two
to four weeks.
It's not yet known if the Zika virus can be transmitted
through vertical transmission. This means that an infected
female mosquito could transmit the virus to her offspring. If
it proves to be true, the female Aedes aegypti could emerge
infectious from their immature aquatic state and be able to
infect people the first time that they bite, shortening the
transmission cycle. It would also mean that from season to
season, eggs that had over wintered could potentially harbor
the virus and it would not need to be reintroduced the next
season.
Also depicted in this slide are other transmission modes,
which would be sexual transmission from a male partner to a
female partner, and then of course, the transmission from the
mother to the fetus. Next slide, please.
[Slide.]
In order to create forecasts of when and where transmission
of Zika may occur, there are many components of the system that
would need to be understood. We can use weather forecasts to
drive models of the mosquito because their biology is largely
determined by weather and climate. As you can see in this
rather complex depiction here, at each stage of the mosquito
lifecycle, you have influences of both temperature as well as
precipitation and manmade filling of the habitat. Not each of
these links is well defined so we use the best knowledge that
we have to estimate the relationships that you see here. The
mosquito component of this model is much better understood at
this point because Aedes aegypti have been studied in the
context of dengue and yellow fever for decades. The top row,
which depicts the human portion of the transmission cycle--
people who are susceptible, exposed, then infectious and then
recover from the disease--is the least understood part of this
cycle.
It's also important to note that while this is a
theoretical model, there are other things that can mitigate
this relationship, things like vector control, socioeconomic
factors, as well as other human activities that could alter
what would be depicted coming out of a model. Next slide,
please.
[Slide.]
In the work that we recently published, we initiated the
process of exploring some of these complex factors in 50 cities
across the United States. What you see on this map is the
relative potential abundance of Aedes aegypti as projected from
a model using average seasonal climate data. On the top circle,
you have the average potential abundance for January, and on
the bottom, the potential abundance for July. Some of the areas
that have the highest projected abundance coincide with areas
where there's been local outbreaks of dengue and chikungunya
viruses already.
The size of the circle indicates the average number of
monthly arrivals from the countries where Zika virus was
circulating in February. The tan shading demonstrates the
distribution of where actual observations of Aedes aegypti have
been made across this area.
The work we published is only a first step towards actual
forecasting. We need better surveillance, improved knowledge of
the virus-mosquito-human interactions, and sustained support
for the infrastructure and dissemination of forecasts.
Thank you.
[The prepared statement of Ms. Ernst follows:]
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Chairman Smith. Thank you, Dr. Ernst.
And Dr. Neafsey.
TESTIMONY OF DR. DANIEL NEAFSEY,
ASSOCIATE DIRECTOR,
GENOMIC CENTER FOR INFECTIOUS DISEASE,
BROAD INSTITUTE OF MIT AND HARVARD
Dr. Neafsey. Thank you. So Mr. Chairman, Ranking Member
Johnson, and Members of the Committee, thank you for holding
this hearing, and for the opportunity to present today. I also
want to acknowledge one of the Committee members,
Representative Clark, an important supporter of the strong
research community we have in Cambridge, Mass.
My research group at the Broad Institute in Cambridge uses
DNA sequencing to understand and control infectious diseases,
and I'm here today to speak specifically about how DNA
sequencing can help us to understand and inform the control of
Zika transmission.
We lack fundamental understanding of how the Zika virus
moves from person to person via Aedes mosquitoes, information
that is crucial for an effective response to this epidemic.
Mosquitoes are not flying hypodermic needles that passively
transmit disease. The successful transmission of mosquito-borne
disease depends on complex biological and ecological
interactions between mosquitoes, their human hosts, and the
pathogens that they transmit.
Insight into the biology of how Aedes mosquitoes are able
to spread disease can be gained through sequencing and mapping
the Aedes genome, or the entirety of its DNA. We know that
because we have demonstrated this with Anopheles mosquitoes,
which transmit malaria.
So I led a project at the Broad Institute recently funded
by the NIH and involving more than 130 collaborators from 19
countries around the world to build genome assemblies or maps
of all the DNA of 16 different kinds of Anopheles mosquitoes,
some of them very proficient at transmitting malaria and some
of them deficient. We learned a lot of things from this project
but--if we can advance the slide--I will show just one small
result. This is a figure that we built by comparing the genome
maps of these different mosquitoes and identifying those groups
of genes that were changing most quickly or most slowly between
these different mosquitoes. As you can see, the most rapidly
changing genes at the top of this list in red are those genes
that we know to influence how mosquitoes taste and smell, and
we know that there're important genes in this class that
determine whether mosquitoes prefer to bite people or animals,
and a strong preference for biting humans is a very important
determinant of disease transmission.
So close behind those smell and taste genes are genes that
provide mosquitoes with an immune system, and we know that
variation in these genes can determine whether or not
mosquitoes are able to transmit pathogens or control infections
and not transmit them to the next person they bite.
So no comparable set of genomic research yet exists for
Aedes mosquitoes despite the fact that they transmit Zika as
well as the three other major viral diseases that Dr. Ernst
mentioned. Next slide, please.
[Slide.]
Here's an image showing the current stage of a recent Aedes
aegypti mosquito genome map. The map is in approximately 3,700
pieces despite the fact that this mosquito has only three
chromosomes, so the target is three. The original map for Aedes
mosquitoes published in 2007 was in about 10 times as many
pieces, so we're making progress.
So as mosquito season begins in the Gulf states and with
Zika on the doorstep of the United States, we lack foundational
resources to pursue DNA-based studies of the biology and
transmission of Zika. This resource gap is critical. Infectious
disease epidemiology has been transformed by DNA during the
last ten years into a rich digital information science allowing
biologists and public health agencies to track the spread of
outbreaks over time and space and learn about what mosquito and
human factors contribute to disease spread. We can now tackle
emergent infectious diseases like Zika using efficient and
innovative genetic tools to build databases and situational
awareness of diseases, and the scientific community stands
ready to develop and apply these tools to the Zika epidemic to
protect vulnerable populations within our borders and around
the world.
One example of that readiness is the Aedes Genome Working
Group organized just this last January via Twitter by Dr.
Leslie Vosshall at Rockefeller University. This upstart group's
mission has been to produce an improved genome map for Aedes
mosquitoes using new sequencing technology that is 10,000 times
cheaper than the technology available ten years ago. With no
central funding but a lot of donated time and resources from a
range of academic and industry partners just motivated to
improve our capacity to respond to Zika, this group has made
rapid progress exploring a spectrum of new technologies for
building an improved genome map.
So with continued support and follow-up research, this map
will yield knowledge that informs disease-control measures.
Examples of such measures include insecticide resistance
detection and surveillance, mosquito population studies, and
genetic modification of the mosquito, new tools for which are
creating an increasingly direct connection between basic DNA
research and control measures.
The Zika epidemic can become a proving ground for the power
of new DNA-based resources and epidemiological tools. Taking
advantage of rapidly falling costs, we can demonstrate to the
world how new technologies will let us understand, anticipate
and control the spread of an epidemic, and we have an
obligation to vulnerable populations to seize this opportunity.
So thank you to the Chairman, Ranking Member Johnson, and
the Committee for your attention, and I'll be happy to answer
any questions you may have later in the hearing.
[The prepared statement of Dr. Neafsey follows:]
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Chairman Smith. Thank you, Dr. Neafsey.
And Dr. Presley.
TESTIMONY OF DR. STEVEN PRESLEY, PROFESSOR,
DEPARTMENT OF ENVIRONMENTAL TOXICOLOGY,
TEXAS TECH UNIVERSITY
Dr. Presley. Good morning, Mr. Chairman and Committee
Members. Thank you for the opportunity to address this
important public health threat. My name is Steve Presley. I'm a
medical entomologist and Professor of Environmental Toxicology
and the Director of the Biological Threat Research Laboratory
at Texas Tech University.
Zika virus, like chikungunya, dengue and yellow fever
virus, is transmitted to humans through the bite of Aedes
aegypti and Aedes albopictus. The biology and behavior of these
mosquitoes differs significantly from vectors of West Nile
virus and other arboviruses in the United States, and these
differences, those unique challenges for controlling them in
urban and suburban areas.
Zika virus infection typically causes less than severe
illness with only about 20 percent of infected individuals
reporting symptoms. Theoretically, a mosquito taking a blood
meal from an asymptomatic but infectious individual could
become infected with the virus and transmit it to other people
being the initial link in establishing local transmission in an
area where no Zika virus cases have previously been reported.
Vectors of Zika virus are mainly daytime biters and they
prefer to be in our houses and offices. They are container
breeders, and they rest in shaded areas during the heat of the
day in the house or outdoors under the eaves of the house or in
vegetation in the yard.
My lab at Texas Tech is a component of the CDC's Laboratory
Response Network, and a certified human diagnostic testing
facility. We're at Texas Department of State Health Services
testing lab for the Zika virus and other high-consequence
infectious diseases. Testing for Zika virus is limited to
designated laboratories using a protocol allowed under the Food
and Drug Administration's Emergency Use Authorization. The
real-time RT-PCR assay that we use detects and differentiates
RNA extracted from dengue, chikungunya, and Zika viruses in
various bodily fluid samples.
The Texas Department of State Health Services is
coordinating an entomology consultation group to develop
strategies and identify resources relative to controlling the
Zika virus vectors. The consultation group is composed of
entomologists and public health professionals engaged in
mosquito and infectious disease research or public health
education. Sixty-six percent of Texas counties have no records
of Aedes aegypti or Aedes albopictus occurrence, and more than
200 Texas counties have not conducted mosquito surveillance
during the last two years. Scientists of the consultation group
are fielding teams to update distribution maps for these
vectors in Texas, and there are numerous reports of insecticide
resistance in Aedes aegypti and Aedes albopictus populations
globally where they occur. The consultation group is
identifying resources to determine insecticide resistance in
these vectors throughout Texas. The consultation group is
drafting Zika prevention information to make available to the
public through various online and social networking
technologies, providing do-it-yourself information to
homeowners on how to eliminate mosquitoes on their property
using off-the-shelf commercial pesticide products and
application equipment.
The American Mosquito Control Association is developing
guidelines for mosquito control by public health agencies and
commercial entities, emphasizing approaches applicable to the
biology and behavior of Aedes aegypti and Aedes albopictus.
All of the Zika virus cases in the continental United
States have been attributed to travel-associated exposure with
no local transmission confirmed. Conversely, there're been
about 800 locally acquired infections reported in America
Samoa, Puerto Rico, and the U.S. Virgin Islands, and only three
travel-associated cases in those areas. This significant
difference between locally acquired and travel-associated
infectious is due to seasonal and climatic differences in most
regions. Currently in most regions of the United States, these
vectors seasonal activity is just now beginning. All efforts
must be made to stay ahead of peak mosquito activity by
immediately implementing comprehensive public health education
programs and enhancing vector surveillance and control
capacity.
I am collaborating with two private companies on projects
relative to Zika virus. One company provides a comprehensive
digital outcome support system for healthcare professionals,
and the other has developed a smartphone-based DNA detection
platform that is field deployable and does not require
laboratory facilities. The device is a real-time PCR
thermocycler that attaches to a smartphone. Results are
provided within 40 to 45 minutes and can be tagged with various
metadata, synced to a web portal for remote access, and we are
planning to conduct field experiments in Florida, Puerto Rico
and Central and South America to validate the accuracy of the
system.
There is a common realization each time an emerging
arthropod-borne disease threatens public health, that being
regardless of how modern medical and scientific technologies
advance, protecting the public health from vector-borne
diseases requires both basic and applied understanding of the
vector's biology, behavior, and vulnerabilities.
Thank you for your time.
[The prepared statement of Dr. Presley follows:]
[GRAPHICS NOT AVAILABLE IN TIFF FORMAT]
Chairman Smith. Thank you, Dr. Presley.
And Mr. Parry.
TESTIMONY OF MR. HADYN PARRY,
CHIEF EXECUTIVE OFFICER, OXITEC
Mr. Parry. Thank you, Chairman Smith, Ranking Member
Johnson, Members of the Committee. Thank you for inviting me to
testify today.
As the Chairman noted, we are facing an unprecedented
challenge of mosquito-borne diseases today. Vector controlling
the mosquito is actually our first line of defense, and it's an
area we've sadly neglected over the past decades, and because
of this, we have seen sharp rises in dengue, we have seen the
introduction of chikungunya, and now we have the Zika
emergency, and I'm sorry to say, but current insecticidal
products are just not sufficient to control this mosquito in
the urban environment.
So at Oxitec, we looked for and developed a new approach,
and that was to use the mosquito against itself. So we have
produced a genetically engineered Aedes aegypti strain, which
we call LX-5138, and it carries two genes. It carries a self-
limiting gene and a color marker. Now, the way this works is,
we release males--males don't bite, they cannot bite--and they
go out and they mate with females. The offspring will all
inherit a copy of the self-limiting gene, and then they die
before becoming adults, thereby reducing the wild population,
and effectively, it's a numbers game. If we can put more of our
males into the environment, the females cannot tell the
difference and more will mate with our males, the offspring
will die, and we'll bring the population crashing down.
The offspring also inherit this fluorescent marker you can
see in the slide that you can't see with the naked eye but you
can see under a light and a filter, and this provides a track-
and-trace-type capability so we can see where our mosquitoes
go, we can see what the effect is that we're having, and we can
moderate the program as we go along in real time.
The releases are made from a truck driven by an operational
plan, which we work out to make sure we cover the whole town,
and we have a GPS system that helps us in terms of decision
support.
The efficacy of this approach has actually been quite
remarkable. In all the outdoor trials we have produced, every
single one we have reduced the Aedes aegypti population in the
urban environment by over 90 percent in about six months, and
that is hugely more effectively than can be done with
insecticides.
Now, safety and respect for the environment are obviously
key factors, and again, in stark contrast to insecticides, we
are just targeting the one mosquito species that is spreading
the disease, so this is a species-specific approach.
Just as important, actually, I'd like to draw two points to
your attention. Our insects do not persist or stay in the
environment. The males we release will die. The offspring will
die. It's a matter of days they will disappear. And also the
marker system means actually that the whole process, the whole
control program, is precision and metric-driven.
I'd also like to stress that in contrast to many other
approaches that have been muted at the moment in response to
Zika, we actually started this in 2002. Our product was
developed in 2002 justified at that time by dengue, and it's
all the more necessary now. And then we started doing outdoor
evaluation in open field trials since 2009, so we have a very
long body of evidence and data to back up both the efficacy and
the environmental side. We've now received national biosafety
approval in Brazil, and indeed, the World Health Organization
has specifically recommended this product for operational use
as part of their emergency responses to Zika. So these are
ready to use now.
In the United States, the regulatory process is actually
still ongoing but we opened a file with the FDA as far back as
2011 in order to conduct a small field trial, which is actually
a very necessary part of the regulatory requirements. The FDA
recently published a finding of no significant impact, but
while we're waiting for the final review and final decision,
we're not able to move forward. But in that same time frame,
2011 to today, in Brazil, we have filed similar applications.
We've carried out several field trials. We've formed a company.
We built a factory. We've got national biosafety release, and
we're now in operational use.
Members of the Committee, I don't think time is on our side
with Zika, and I think the utmost urgency is required in every
area. I've come from Puerto Rico, and we could have a
catastrophe on our hands if we're not careful. At any one time,
there are 28,000 women pregnant, and that is a very salutary
thought when you think that summer is coming up and we have
active disease transmission.
So in view of that urgent health need, we'd urge your
support actually to give the FDA all your support and
encouragement so they can expedite approval of our application,
and I would also urge consideration of an emergency use
authorization actually, which is used sometimes to bring
forward new medication or diagnostics, but I think the fact
that we have such an urgent and pressing need means the FDA
needs more tools at its disposal in order to help protect
Americans. We want to make this technology available in the
coming months rather than the coming years.
Thank you very much.
[The prepared statement of Mr. Parry follows:]
[GRAPHICS NOT AVAILABLE IN TIFF FORMAT]
Chairman Smith. Thank you, Mr. Parry.
Let me direct my first question to Dr. Presley, Dr. Ernst
and Dr. Neafsey, and let me say initially, though, that we have
two countries, Brazil and Colombia, where there are thousands
of cases of individuals with the symptoms from Zika virus. We
know that for every one who has a symptom, there are 20 others
who are infected. We also know that over 99 percent of those in
the United States who have become infected and have the
symptoms contracted the Zika virus because of travel outside
the country. So my question is this: Don't you feel that the
Federal Government should issue a travel advisory that says
that at the least, pregnant women and perhaps others, should
avoid all nonessential travel to those two countries and
perhaps others? Dr. Presley?
Dr. Presley. Yes, sir, Mr. Chairman. I believe that the
potential for people to travel to countries where the Zika
virus transmission is actually occurring and then bring back an
infection, they may be asymptomatic, but I believe stricter
travel restrictions or advisories should be implemented.
Chairman Smith. Okay. When you say that we should suggest
that those traveling from the United States to other countries
avoid all nonessential travel, are you talking about just women
or a wider group?
Dr. Presley. I'm talking about any nonessential travel from
the standpoint of the few cases of sexual transmission were
from male partners that came back, and I know at least one of
the cases was a woman. A partner had become infected.
Chairman Smith. So the government should issue a warning
that says avoid all nonessential travel to Brazil, Colombia,
anywhere else?
Dr. Presley. I believe so, sir.
Chairman Smith. Okay. Thank you.
And Dr. Ernst?
Dr. Ernst. I would say that definitely for pregnant women
that it would be advisable to have them restrict nonessential
travel but also to make sure that they understand if they are
going to an area and they do choose to go to an area, that they
look at the geography of the risk. So it is possible that in
some of these countries where Zika virus is being transmitted
that there are high-altitude locations and other locations
within those countries that do not have Zika transmission or
even the vector that is present so really trying to understand
more specifically where they're going and working with their
doctor to get advisement on whether or not it is important for
them to----
Chairman Smith. I think I saw a map, at least of Brazil,
perhaps of Colombia, that showed over half the country was
actually below the 6,000-foot altitude, so it seems to me--but
you do agree at least for pregnant women that there should be
an advisory to avoid all nonessential travel?
Dr. Ernst. Correct.
Chairman Smith. Okay. Thank you.
And Dr. Neafsey?
Dr. Neafsey. Sure. I think this question probably falls
closer to the expertise of my co-panelists, but I think it
would be reasonable to advise caution, especially for pregnant
women who might consider traveling to a Zika-endemic area. But
to echo what Dr. Ernst mentioned, beyond geographic
considerations and altitude, there are also seasonal dynamics
that really contribute to Zika transmission, so it's----
Chairman Smith. What would be the most dangerous time of
the year to travel?
Dr. Neafsey. Oh, I think the hot, wet time of the year.
Chairman Smith. Summer?
Dr. Neafsey. Yes, but I think at this stage it's very
difficult to quantify exactly what that represents.
Chairman Smith. Okay. Thank you.
Second question to Dr. Presley and Mr. Parry, and that is,
what are the best preventative measures that we in the United
States could take to try to avoid contracting the virus?
Dr. Presley. Because the biology and behavior of these
vectors is completely different than the mosquito vectors of
West Nile virus or other arboviruses, the immediate concern or
the immediate action is, I believe prevention from the
standpoint of educating the public. These mosquitoes are called
backyard mosquitoes for a reason because they like to live
around people and in their yards, so the pesticide application
technologies and approaches that are used now are pretty much,
at least throughout most of the country, is driving down the
street in urban areas dispersing a fog or a spray or an ultra-
low-volume insecticide that doesn't reach into the backyard,
and so the control strategies with pesticides is going to take
much more applied when you target an area where active
transmission could be occurring, go in and kill the mosquitoes
in the yard, and that may be a homeowner-driven----
Chairman Smith. Almost on an individual basis?
Dr. Presley. Yes, sir, become the individual homeowner
until we have a technology like genetic modification like the
sterile screw worm release
Chairman Smith. Thank you, Dr. Presley.
Mr. Parry, my time has expired, so could you briefly
respond?
Mr. Parry. Yes. I think we can actually target the mosquito
now and drive it down to a level where it can't transmit
disease. I firmly believe that. I think it's an integrated
approach. I wouldn't just rely on our technology but I think
our technology provides the missing piece of the jigsaw, but
really, we have now with our technology added in to what we
have already a way of controlling this mosquito in urban
environment and we should focus on the high-risk areas as a
priority.
Chairman Smith. Okay. Thank you, Mr. Parry.
The gentlewoman from Oregon, Ms. Bonamici, is recognized
for her questions.
Ms. Bonamici. Thank you very much, Mr. Chairman, and thank
you for convening this expert panel of witnesses. It's been
very enlightening. I have about 5 hours of questions but I only
have 5 minutes, so I'm doing to start.
Dr. Ernst, you said in your written testimony that we don't
know the complete distribution of the Aedes aegypti in the
United States because surveillance for the mosquito is not
consistent across jurisdictions and many don't have the
resources to carry out the surveillance needed, and Dr.
Neafsey, you talked about a different of mapping, the genomic
mapping. So can you each address how close are we? Are we
halfway there? Are we 25 percent there? And maybe just a
mention of where we are in terms of resources as well, and then
I want to have time for another question or two. Dr. Ernst?
Ms. Ernst. I will try and answer briefly. So I would say
that it's very spotty where we have the surveillance data that
is actually accurate and well collected. Some places do a great
job and have a significant amount of resources. The majority of
places do not. There are West Nile virus vector surveillance
that is ongoing but the distribution, the way the ecological
niche is for the Aedes aegypti mosquito, it's different, so you
have to have different traps and different location of those
traps. I would say at least 80 to 90 percent of the actual
jurisdictions probably do not have active Aedes aegypti
surveillance at this time.
Ms. Bonamici. Thank you.
And Dr. Neafsey, on the mapping, how close are we, or how
far are we, depending on how you look at it?
Mr. Neafsey. I think we're close. I think we're making good
progress towards having a better genetic map, but I think
having a better genetic map for the mosquito is a proximal goal
and the goal of applying that map most fruitfully to studies,
for example, of insecticide resistance and identifying those
markers that are most useful in the field for maintaining the
efficacy of the control measures we do have. That will take
further application of the genome map and testing of more
samples.
Ms. Bonamici. Thank you. And many of you mentioned the
urgency because of the summer weather that's approaching. It's
almost June. Does anyone disagree that it's becoming more
urgent as the weather is getting warmer across the country and
the world? Anybody disagree with that?
So my next question is really for each of you. I was really
surprised to learn that the Aedes aegypti mosquito can breed in
a bottle cap of water. I don't think that this is what people
think about when they're warned against keeping standing water
around, and I know, Dr. Presley, you addressed this need for
public health education, but what efforts are underway to
educate people, and is there social science research about the
most effective ways to communicate these kinds of messages? Are
there--do we need more behavioral research on how to send the
messages with urgency so that they'll be understood and acted
upon? Dr. Presley, do you want to start and then I'd like to
hear from the others as well.
Mr. Presley. Yes, ma'am. There's efforts underway in Texas,
I know for sure, to put out using social media and online
resources. There's programs, there's web pages that CDC has.
There's a lot of information out there.
I did a Zika virus search last week and found 91 million
results so----
Ms. Bonamici. I don't mean to interrupt, but maybe that
gets to the heart of the question. Is somebody sees 91 million
results, how do they know where to go to get something that's
effective? Are there--is the CDC known as the reliable source
and the others are--you know, everything we read on the
internet isn't true so how do we get that message across in an
urgent way?
Mr. Presley. In Texas, in the local area I'm from, we're
sending it out in utility--little flier, a pamphlet in utility
bills, and they're going to do that--they started that in May
and they're going to follow through the summer with that.
That's really the only way that we found to make sure everybody
at every level gets it.
Ms. Bonamici. Okay. I know a lot of people pay their bills
online so I just don't know if we're doing what we need to do
to reach people to get the message across. I think people are
thinking well, if I have a pond I'm in trouble but otherwise
I'm not, so how do we communicate that?
Dr. Ernst, do you have thoughts on that?
Ms. Ernst. Sure. So we're doing a couple of things. One is
try and engage people in social media but also to try and link
that social media to whether or not it actually makes any kind
of difference because there is a lot of advertising and there
is a lot of information that's out there but whether or not
that actually translates into action on a person's part is
unknown. We are also developing a mobile application that
people can subscribe to that has an educational component. I
think that making sure that there is a cohesive on-the-ground
network so in the area where I'm from, promotoras and community
health workers can get that information out to areas where
there are fewer resources and actually have one-on-one contact
with most vulnerable communities.
Ms. Bonamici. Terrific.
And Dr. Ernst, quickly, you mentioned that we don't know
how different environments and different environmental
conditions may change the feeding habits. If somebody
researching that, and what would that research tell us if we
could answer those questions? How would we use that
information?
Ms. Ernst. Right. So in Phoenix where there's a fairly good
vector surveillance and control program, they actually noted
that the Aedes aegypti mosquito were altering their biting
behavior and were biting as early as 3 or 4 in the morning.
Now, that's anecdotal. They have not met published that
information. But it seems like this is a very flexible
mosquito, and it is able to modify its behavior in order to
survive.
Ms. Bonamici. Fascinating. Thank you, Mr. Chairman. I yield
back.
Chairman Smith. Thank you, Ms. Bonamici.
And the gentleman from Oklahoma, Mr. Lucas, is recognized
for his questions.
Mr. Lucas. Thank you, Mr. Chairman, and before I begin my
questions, I would note that having known Dr. Presley since his
graduate days at Oklahoma State, I have a little sense of co-
ownership along with Congressman Neugebauer down there.
That said, Doc, let's turn to you for a couple of
questions. Number one, in addressing the issues, and the
panel's laid out very well today the challenges we face, the
ultimate goal of what we try to do, but there's the short-term
solution and there's the long-term solution. Talk for a moment
about--and you discussed this earlier--about the mosquito
control perspective for a homeowner, whether it's Lubbock or
Stillwater or anywhere where this may be an issue. You've
described how the traditional mass fogging systems going down
the street won't get everywhere. I know historically in the
past, we've done aerial spraying in certain cases. As I talk to
my constituents, the off-the-shelf products you're taking
about, what kind of cost are we talking about for a homeowner
to protect him or herself in their backyard? It's not
particularly expensive, correct? It's the efforts involved?
Dr. Presley. No, sir, you can buy a home thermal fogger,
which creates a cloud, a smoke cloud, essentially, in your
backyard that will penetrate vegetation and you can buy the
pesticides. You can buy the thermal fogger for a couple hundred
dollars, a very good one, and then the pesticides may be $20 or
$30 a month to keep mosquitoes down in your yard.
The issue with these mosquitoes, albopictus and aegypti, is
they stay pretty close to where they are hatched, about 200
yards, 300 yards in an area. The foggers that drive up and down
the streets are really for mosquitoes like culex tarsalis that
vectors West Nile virus, and that with restrictions and how
we've refined pesticide application, you're relying on a small
droplet of that insecticide impinging on the mosquito while in
flight. That's effective for crepuscular biters, or mosquitoes
that bite at night or between, you know, sunset and dusk and
dawn, because with Aedes aegypti and Aedes albopictus, they're
daytime biters primarily. So spraying with the fogger depends
on before the thermal inversion occurs. When the sun comes up
and the ground begins to heat, the currents are upwards, so
these fogs, these clouds that you spray out of a ULV machine
driving up and down the street will rise and dissipate. You're
trying to get with these daytime biters treating early in the
morning with a fogger or a thermal fogger or a spray, just a
wand spray treating under the eaves of houses, around doors and
windows and vegetation. It's a completely different strategy
for vector control. It comes into private property issues, all
of that.
The homeowner is going to be responsible for dumping that
bottle cap full of water or that toy dump truck in the backyard
or anything that can collect water is a good breeding site for
these mosquitoes.
Mr. Lucas. But our fellow citizens have the ability to
protect themselves if they'll take action based on the right
information?
Dr. Presley. Yes, sir, and there are numerous over-the-
counter, off-the-shelf products that can be bought at any big-
box garden store or home improvement center.
Mr. Lucas. Now let's go to the next step, Mr. Parry
discussing an effort at a long-term solution. You mentioned the
screw worm program so successful since the 1950s that most
people don't even know it exists. Would you expand on the
problem we face in the Southwest, in the South, for that
matter, what the solution was and how it has continued to be
effective since then?
Dr. Presley. Oh, the sterile male release of screw worm
flies. The primary screw worm, they're a blowfly. They would
oviposit or larviposit their maggots into a wound, and that
particular screw fly would eat living flesh. Other blowflies
will----
Mr. Lucas. And any cattleman 65 years or older in Texas or
Oklahoma will tell you it was a horrible thing.
Dr. Presley. And not only cattle, wildlife--whitetail deer,
everything was affected. They came up with a sterile male screw
fly release program where they irradiated the males and
released them. This particular species only bred once, the
females, so it stopped the progression, and it essentially
stopped----
Mr. Lucas. For 50 years now.
Dr. Presley. There still are cases but it's very
controllable and managed on the Texas border now.
Mr. Lucas. So we have a track record of using these type of
technologies to make a real difference systematic in the long
haul?
Dr. Presley. Yes, sir.
Mr. Lucas. Thank you, Doctor.
I yield back, Mr. Chairman.
Chairman Smith. Thank you, Mr. Lucas.
And the gentleman from California, Mr. Bera, is recognized
for questions.
Mr. Bera. Thank you, Mr. Chairman.
I'm going to put on my doctor cap here and public health
perspective so with regards to travel advisory for those
listening at home, just go to CDC's Zika Travel Advisory, and
you'll get a lot of information and country-specific
information.
Going back as far as February, the advice has been, if
you're pregnant, do not travel to endemic areas. If you're of
childbearing age, the advice is not to travel to endemic areas,
but if you are going to travel, to take precautions--birth
control, et cetera. We've also been working with global health
agencies to increase access to birth control in endemic areas
until we get ahead of Zika virus and we fully understand what's
going on.
If you have to travel to these areas, obviously take
mosquito precautions, you know, repellants, et cetera avoid
going out at dusk or the times the mosquito's biting.
In addition, you know, back in February, we had a hearing.
We had Dr. Frieden and Dr. Fauci come over from the National
Institutes of Allergies and Infectious Disease. Dr. Fauci at
that time was quite optimistic that by the end of the year we'd
have a vaccine for clinical trials. I will be honest, I was
skeptical that we'd be able to develop something as quickly as
that.
You know, a few weeks ago I had a chance to go visit Dr.
Fauci and his team at the National Institutes of Health. They
will be ready for clinical trials, phase I trials, starting in
September, and a very important aspect of our getting ahead of
Zika is that vaccine development, and the science behind
vaccine development. So, you know, September is still after
mosquito season but we are moving fairly rapidly to get ahead
of this and address it.
The bigger component here, though, and each of the
witnesses touched on this, is two years ago we were talking
about Ebola, we're talking about Zika this summer, and the
world is a much smaller place right now, and vectors,
infectious disease viruses move much more quickly. It's not as
though we haven't known about Zika for, you know, years. We've
known about this since the 1940s. And it's not that the virus
has mutated. The virus has moved. It's now in a densely
populated area and, you know, we are starting to see this pop
up, and what we have to do is as a body is, provide adequate
resources to the CDC, to the NIH to do the research but to
understand that we are going to be battling these infectious
diseases much more frequently, and we've got to support the
science.
Dr. Ernst, I'll probably toss it over to you. With regards
to both Zika--you know, certainly as we get a vaccine
developed, disseminating that vaccine and making sure it's
effective, but then also just more broadly as an epidemiologist
and someone who studies this, you know, what we ought to be
doing right now to prevent the next infectious disease and how
we ought to be thinking about some of this.
Dr. Ernst. So you're talking more broadly, any infectious
disease?
Mr. Bera. More broadly, yes.
Dr. Ernst. More broadly? I mean, I think some of the things
that we can do is really understand where a lot of these
infections are originating from. A lot of these are diseases of
poverty. They're diseases where you have countries and places
that have no infrastructure to be able to respond and control
the epidemic in their own boundaries, and when you have
something that is going on in another place and you have, as
you said, a very globalized world, it doesn't take a lot for
those viruses or bacteria to come over here.
So I think shoring up resources in other places to ensure
that there's fewer pandemics in those areas as well is a
critical step, and then also investing in research and
understanding where those threats might be more likely to come
from is also very important.
Mr. Bera. Wonderful. And again, I think for the public and
for my colleagues in Congress, it is very important that we
don't just fight the disease here, that we actually go to where
these infections and these viruses are endemic and originating,
and there's a reason why we fund global health, there's a
reason why we, you know, fund the CDC to go do research and go
to these endemic areas, and as we look at these fundings and we
look at our budgets, it's really important for us, because if
we don't get ahead of this in those endemic places where the
virus is, they will certainly pop up here, and we've seen it
time and time again with SARS, with, you know, various
infectious diseases, and again, in a smaller world, we will see
this more frequently.
You know, I'm running out of time. As Ms. Bonamici said, I
could spend, you know, 5 hours asking questions, but we also
have to then adequately fund the science as well so we can come
up with those therapies to both control the vectors but then
also to get ahead of this, and with that, Mr. Chairman, I'll
yield back.
Chairman Smith. Thank you, Mr. Bera.
The gentleman from Texas, Mr. Neugebauer, is recognized.
Mr. Neugebauer. Thank you, Mr. Chairman.
The United States has been very lucky that many of the
potential global health pandemics have not become epidemic in
the United States. However, it's a little puzzling to me
because you know, some of these things like Ebola and Zika have
been around for a very long time, but what happens is,
something kind of elevates their attention and then there's a
call then for the Federal Government to come and spend billions
of dollars to be in a reactive mode.
So I guess my first question to the panel this morning is,
rather than being in a crisis mode on some of these things,
what would be a better plan? Because I think what I always find
is when we have crises, we don't spend money as efficiently as
we do when we spend money when we're planning for it, so kind
of go down the panel, and in a perfect world, how can we get on
the front of some of these rather than being in a reactive
mode?
Dr. Ernst. So I would concur with that. I absolutely agree
that the reactive mode that we seem to be in, in terms of
pandemic response and planning, is not as efficient. I think we
have made some strides towards trying to be more ahead of the
curve. We had a lot of preparedness funding that has come
through the health departments to try and set up some of these
response plans in place, et cetera, but I think we can do more.
I think that we need more investment in trying to understand
where and when and forecast some of these risks and be able to
quell them before they can even actually start taking off, and
that means having really better surveillance systems globally
as well as even improving our surveillance systems here
domestically.
Dr. Neafsey. All right. So I second, you know, the
importance of surveillance, and I can speak to work being done
by one of my colleagues at the Broad Institute, Pardi Savetti,
who was well positioned to apply DNA-based studies of the Ebola
outbreak because she was establishing a research base in West
Africa and starting to characterize fevers of unknown origin.
There are many agents of infectious disease that result in
symptoms and that are undiagnosable because we don't know what
the agent is, and there are many of these, particularly in
tropical parts of the world, any one of which could in
principle emerge to cause an epidemic.
So I would advocate the importance of surveillance, the
importance of catching new epidemics early, and the utility of
DNA-based studies for getting an early characterization of
perhaps the agent behind emerging outbreaks.
Dr. Presley. I agree completely with what's been said. I'm
much more applied in how I study vectors. It's more not at the
genetic level, it's more transmission dynamics, how they
behave, the ecology of the vectors. That is where I believe
funding also needs to be focused. You're right, this
``everybody panic and throw money at it'' doesn't fix it, and I
said it before. The Zika virus is just the latest of an
emerging arthropod-borne threat, public health threat, in the
United States. We had chikungunya last year, Valley fever
before that, and we'll have more because there are viruses out
there that we know or suspect are vector-borne but they're not
in areas where we're really concerned right now. West Nile
virus had never occurred in the real world until 1999. Zika
virus wasn't in South America until last year, 2015. So viruses
are moving around, and that's part of--whether it's climate
change or global travel, speed of travel, they're moving
around.
My basic belief is that we need to start at the applied
level and train pest control operators. We saw a kneejerk
response to Ebola where nurses and clinicians did not have the
proper personal protective equipment, the most basic of
supplies they need. I can draw a similar situation with vector
control operators in mosquito control districts throughout the
country right now. They don't have those basic supplies they
need knowledge-wise and resource-wise to attack this issue.
Mr. Parry. I think you have to look at the common element,
and the common element is the mosquito. Control the mosquito,
you control all the diseases that it has spread, is spreading,
and will spread.
When I say control, I mean giving yourselves the capacity,
the tools, and the procedures to exercise that control. In some
areas, some may wish to eliminate the mosquito. In other areas
one may wish to have the ability to drive it down below a
disease transmission threshold, which is not actually the same
as elimination. But having that capacity, having that ability
to do that to me is the absolute starting point of it.
Mr. Neugebauer. Thank you, Mr. Chairman.
Chairman Smith. Thank you, Mr. Neugebauer.
And the gentleman from California, Mr. Takano, is
recognized for his questions.
Mr. Takano. Thank you, Mr. Chairman.
Mr. Parry, what you propose makes rational sense,
statistically drive down the numbers of the mosquito control,
the vector. Mr. Lucas mentioned the sterile--the sterilization
of the male insect. Your process, though, is not sterilization,
it's about a genetically modified mosquito, and there's some
concerns of some environmental groups about the safety of this,
and there's some rumors that this genetically modified mosquito
actually transmits the virus. Can you just quickly clear that
up? Because I have a lot of other questions I want to ask.
Mr. Parry. Yes. I mean, our mosquito is modified in two
ways. It can't reproduce, and it carries a color. It's no more
or less capable of doing anything else than normal mosquitoes.
There is no difference. In terms of the environment, actually I
think our mosquito is far safer and softer on the environment
than any other intervention. It's not a toxin. You're just
taking out one insect. You're not affecting the rest of all the
food chains.
I think it is a shame in many ways that there has been a
concern over the words ``genetic modification'' in society.
That's been there for several years now. And really, we need to
be able to distinguish products by what they are, what they do,
what the risk profile is, rather than assign a tag or a label.
But ultimately, with our product, it's like any other.
It's--we provide the evidence to the actual arbiter. At the end
of the day you go through the regulatory process. The evidence
is weighed up and you have an outcome that's based on science
and facts.
Mr. Takano. So with respect to Zika in this particular
case, it seems controlling the vector is really important to
keep what transmits the virus from doing that, and so reducing
the numbers of mosquitoes is really important but also coming
up with better technologies on repellants.
In my own district, the University of California Riverside,
which is known as a great center of entomological research--I
see a lot of nodding heads. Dr. Neafsey, are you familiar with
Olfactor Laboratories, which is an attempt to monetize the
research that was done in a laboratory by Dr. Anandasankar Ray,
who is basically focused on trying to deal with the carbon
dioxide receptors of the mosquito. You mentioned that some
mosquitoes are able to distinguish between human and animals,
but what's common is that they're kind of attracted to this
carbon dioxide marker. Is that right?
Mr. Neafsey. So yes, that's right. I think there are a
number of cues that lead mosquitoes to their host for a blood
meal. Carbon dioxide is one such cue. What is amazing is that
many mosquitoes, particularly those ones that are most culpable
in transmitting human diseases, are very human specific so
they're responding to carbon dioxide but they're also
responding to other unique signatures of human odor. I think
developing repellants, developing strategies that capitalize on
our rapidly growing knowledge about the molecular biology and
the neurobiological basis of how mosquitoes perceive these cues
is a fantastic research direction and I think you've cited a
good example of how it's actually translating into intervention
measures of repellants.
Mr. Takano. This is a great example of how basic scientific
research in a laboratory has these very practical effects and
is being furthered by private-sector-funded efforts to monetize
that research. I understand that they've developed a patch,
something called a Kite patch, which can just be worn on
clothing which interferes with the mosquito's ability to
perceive these--what do you call them?--these markers or----
Mr. Neafsey. Cues.
Mr. Takano. Cues. The cues. The cues, the chemical cues.
What's exciting about that is that it seems less--has less
impact on the environment with the use of these pesticides. So
this is a very promising line of research is what I perceive.
Mr. Neafsey. Absolutely. I think we're positioned now
rather than to use sort of a random strategy for finding
chemical repellants or other interventions, we can really use
our knowledge to pursue these strategies with a rational basis,
with a thorough understanding of the mosquito biology, and
these have great potential.
Mr. Takano. Well, I hope that we can work together on both
sides of the aisle to promote a number of strategies to deal
with this vector.
Mr. Parry, you certainly propose, I think, a very rational
strategy, and Dr. Neafsey, you've confirmed my excitement about
what's going on in my own district on this research, and to the
extent that we can buttress what's going out there--and Dr.
Ernst, what you say about global poverty and making sure that
we take care--that there can be no weak link. We can't allow
any country to have a dysfunctional public health system. It
comes back on us.
I yield back, Mr. Chairman.
Chairman Smith. Thank you, Mr. Takano.
And the gentleman from Louisiana, Mr. Abraham, is
recognized.
Mr. Abraham. I thank you, Mr. Chairman. I think we
certainly have a great panel here, and with your minds and
minds out there working on this, we can probably cure this
issue.
Going back to Congressman Neugebauer's argument of being
reactive instead of proactive, the Federal Government is
unfortunately often reactive, in my opinion, and it's like
sending the Hindenburg to rescue the Titanic. We need to be
better than that. We should be better than that at this stage
of the game.
Mr. Parry, the CDC, I think in February, elevated Zika to a
level one activation, and you can help me, but I think I recall
that the only other time was Ebola was active one, H1N1, and
being in Louisiana, I remember post Katrina was a level one
activation. So my question to you is, you've got evidently
something that works here. You said you could get a 90 percent
reduction in mosquito population in six months, which is, to
me, a phenomenal feat. If CDC thinks this is so important, and
I can assure you, it's very important--I've treated
microencephaly and microencephalitic children, and it's a
horrible, horrible thing for a child to undergo that, and their
parents also--what is the FDA telling your company as to why it
won't give you an emergency declaration? I mean, you've been
after this since 2011 according to your testimony. We know this
is bad. We don't want any child to be born with microcephaly or
microencephaly. What's the answer FDA is giving you to why
can't we do this now?
Mr. Parry. The answer we have received is, it's
complicated.
Mr. Abraham. Well, come on. We've got wonderful scientists
here including yourself that tells us we need to act now. We
should have acted a year ago.
Mr. Parry. I absolutely agree. We're being treated as an
investigational animal drug as the sort of product class, if
you like, because the genetic modification is a DNA insertion,
which means that from the FDA perspective, they would have to
approve an animal drug in order to provide a public health
benefit.
Mr. Abraham. But you've got objective data that says this
works now.
Mr. Parry. Exactly, and I think that's exactly the way we
should go. We need to go down the emergency----
Mr. Abraham. We've got to kill these mosquitoes. I mean, I
understand, look, I think it's critically important what we've
talked about, better repellants like Mr. Takano said, certainly
spraying individually, but until we kill the mosquito, we can
kill all we want to in our house but they're going to come back
in. Mosquitoes are going to come from the islands, they're
going to come up from the South. We've got to quit putting
Band-Aids on this. We've got to go to the root cause. The root
cause, like you alluded to, is a mosquito, and somebody asked
about pandemics worldwide, and again, yellow fever, dengue,
malaria, all these are vector-borne, and we've got to kill the
source.
So, you know, I'm very frustrated as I am with many
government agencies, unfortunately, but with the FDA in this
instance, it's out there, we know it's here and we need to do
something, but they're putting up blockages to your company and
other companies like yours.
Mr. Parry. I think we should encourage them to find the
processes to make this happen.
Mr. Abraham. Is the cost of your technology any more costly
than spraying, traditional spraying?
Mr. Parry. I think in terms of cost efficacy, ours will be
streets better, to be honest.
Mr. Abraham. Okay. And to the panel, I've just a couple of
science questions. Is this an intracellular or an extracellular
virus? Does it live in the RBC, the WBC or is it in the plasma?
Where does it live in the human?
Mr. Neafsey. I think it replicates in cells, and I think
work is underway on elaborating exactly which cell types are
most favored by the virus. I think there was this convincing
work a few weeks ago with brain tissue organoids to establish
its affinity for developing around the cells, but I would say
that the preferences for the types of cells infected by the
Zika virus are still being elaborated upon.
Mr. Abraham. And Dr. Ernst, you said that certainly the
mosquito vectors like the Aedes aegypti and the albopictus
transmit not only Zika but other diseases such as dengue,
yellow fever. When a mosquito that's infected with Zika and
those other diseases bites somebody, are both viruses or more
than one transmitted at the same time, or does Zika take
precedent? Who wins that battle?
Dr. Ernst. That's a good question. I don't think we know
that yet. There's certainly some evidence that mosquitoes can
be co-infected with dengue and chikungunya but I'm not sure
what the status of the research is right now on the
interactions between dengue virus, for example, and Zika virus.
I don't think we know that yet.
Mr. Abraham. And one quick question. My time is out. After
somebody's infected with Zika, is there antibodies built up?
Can we test for antibodies in that person?
Dr. Ernst. Yes, we can test for antibodies for Zika but
it's very difficult to disentangle if the person has had a
previous dengue infection. Then when you try and test for
antibodies, it becomes equivocal. The results become very
difficult to interpret.
Mr. Abraham. Well, Mr. Chairman, I have a thousand other
questions also but my time is up so thank you very much for
allowing me to go over.
Chairman Smith. Thank you, Mr. Abraham, and the gentleman
from Colorado, Mr. Perlmutter, is recognized.
Mr. Perlmutter. Thank you, Mr. Chair. This is a very
fascinating hearing, and obviously--my question is going to be
a little more parochial. I'm from Colorado. Looking at those
maps that you presented to us, we're not really in the region
that can anticipate Zika, the Zika mosquito, the egyptus or
whatever it is.
So I'd like to start with you, Professor Presley, because
you mentioned West Nile, which is something that we'll get a
couple cases of West Nile in Colorado pretty much every year.
Can you just for a layman like myself kind of explain the
difference between the mosquito that delivers West Nile versus
the mosquito that delivers the Zika virus? And then, you know,
how are we managing West Nile mosquito versus the Zika
mosquito?
Mr. Presley. The West Nile vector is--and I'm not sure what
part of Colorado you're talking about.
Mr. Perlmutter. Denver area.
Mr. Presley. On the high plains?
Mr. Perlmutter. Yeah.
Mr. Presley. It's culex tarsalis, and that mosquito breeds
in pools and ponds, standing water, so we can survey for them.
Their activity is primarily crepuscular, right after dark and
right before sunrise. Contrast that to Aedes aegypti and Aedes
albopictus that are vectors of Zika virus, and they like to--
they're container breeders. It's fresher water typically in
small containers in the axles of----
Mr. Perlmutter. When you say small containers, tell me what
you mean by small containers. I'm trying to think. You ship
them in boxes or what?
Mr. Presley. A tuna can is more than--an empty tuna can is
more than enough water. They will breed in the leaf axles of
vermillion plants like in the house. You know, a comment was
made about just outside. No, these mosquitoes will live in the
house. They like to be in the house, hotel rooms. So just
treating the outside doesn't control them. So these differences
in where they breed and where they like to bite and rest are
significantly different. You know, they're daytime biters, and
it's really right after sunrise--typically right after sunrise.
Then they rest during the heat of the day and they bite right
before sunset when it cools back down. That's not a rule but
that's generally.
Mr. Perlmutter. So in controlling them--and Mr. Parry,
maybe I'll direct these questions to you for a second and then
to the whole panel. So--and I don't know the Latin term but
I'll call them the West Mile mosquito and the Zika mosquito. In
your use of more or less a sterile male to defeat the virulent
female or, you know, cause the death of the species, do you
guys do any work on the West Nile mosquito?
Mr. Parry. Not yet. So we've obviously developed aegypti.
We can do anopheles, which is the malaria mosquito. We've
actually done proof-of-concept work there. We're actually
developing Aedes albopictus, which was also mentioned earlier,
so that is actually coming through the R&D system and is a
candidate product.
With the culex mosquitoes, the West Nile ones, we've looked
at those. We think they're very tractable actually. We can do
them. The research team is very confident but we haven't proven
that yet.
Mr. Perlmutter. In Colorado, I think Professor Presley, we
have up at Colorado State University, you know, studying the
Zika virus and mosquitoes. Do we--I guess my question is, the
symptoms of West Nile can make you--you get really sick. More
negligible obvious symptoms with the Zika virus but the
potential damage to the fetus or to the baby is tremendous. So
I guess my question is similar to Mr. Abraham's, we ought to be
allowing every possible defense whether it's using an
insecticide or sterility, and I would--on the insecticide part
of this, do we have any breakthroughs? It sounds like Mr. Parry
has a good approach on the sterility. Do we have any
breakthroughs on the insecticide piece of this against the Zika
virus and the Zika mosquito?
Mr. Presley. We do, Congressman. There are some very
effective pesticides, but the whole insecticide resistance
issue in these species is critical, and we don't know where
resistant populations are. In the State of Texas, we're going
to find out in Texas, but there needs to be, I think, a
national effort where these mosquitoes are documented to occur
to find out what insecticide resistance does exist in the
population so we can knock them down immediately and then rely
on long-term strategies to keep them numbers down.
And I would just add in that West Nile virus when it first
occurred and during the first few years of its occurrence in
the United States was considered to be West Nile fever
predominantly, which was relatively mild symptoms. Now it's
predominantly West Nile neuroinvasive disease. The virus has
changed over time. We don't know what Zika is going to do
because it's only been in the new world in South America for a
year. There's a lot of challenges there.
Mr. Perlmutter. Thank you, Mr. Chairman.
Mr. Parry. I had a point.
Mr. Perlmutter. Oh, go ahead.
Mr. Parry. Sorry. I know that's not done, but I'd just like
to add a point.
The issue of insecticide resistance is a very real one, but
when you get to the Aedes aegypti, which is the Zika
transmitter, the biggest issue is private property actually
because this mosquito lives in and around the home. For
chemicals to be effective, you've got to have a public health
authority coming into your house, your child's bedroom, your
kitchen pretty much every week, and that doesn't work with
modern society.
Mr. Perlmutter. Thank you.
Chairman Smith. Thank you, Mr. Perlmutter.
And the gentleman from Alabama, Mr. Palmer, is recognized
for his questions.
Mr. Palmer. Thank you, Mr. Chairman.
Dr. Presley, given that the symptoms of Zika virus in
adults are associated with a host of other ailments, how likely
is it that a general practitioner may not have seen a case of
Zika and therefore be able to accurately diagnose it?
Dr. Presley. Excellent question, Congressman. You know, we
say the facts that are out there or the information out there
is that only 20 percent are symptomatic with infections. Flu-
like illness of influenza-like illness is so common in talking
to my physician friends, how many infections are we saying, it
looks like a virus, go home, rest, plenty of fluids, you'll be
fine, and it never gets tested. So I think that these estimates
of the number of infections in an area are way underestimated
but there's no way that you can nail that down. It's like West
Nile or flu, influenza.
Mr. Palmer. Do physicians have the necessary diagnostic
tools? I mean, is there something out there that they could use
to make sure they make a more accurate diagnosis?
Dr. Presley. The current restrictions on human diagnostics,
and my lab is one lab that does that but there's certain
criteria both clinical and epidemiological criteria like have
you traveled or been exposed to somebody that did travel in a
Zika infectious area, and then the local public health
authority has to authorize that test being performed. Those
tests, diagnostic assays, can only be done at CDC LRN
laboratories, and we've done a couple over the past few weeks,
but it's a long administrative trail.
Mr. Palmer. It sounds like we need a kit, some----
Dr. Presley. Yes, sir.
Mr. Palmer. --something like that. Let me move on. Thank
you for your answer.
Dr. Ernst, in your testimony you described the Zika map
that you helped developed to try to predict where Zika might
spread in the United States. Have we stopped short of calling
it a forecast because there's still too many unknowns? How
would you improve your model to provide a better forecast for
Zika or other vector-borne diseases and what resources would a
team need to provide a better forecast?
Ds. Ernst. So I think there are several key components that
would be helpful to improve for model results. One is being
able to have better validation. So we were lucky enough to find
a couple of data sets to validate our model outputs, but as has
been mentioned multiple times, having actual robust
surveillance programs that allow us to test our results against
the actual data is one step. Another step is having more
information on the specifics of the host vector interactions,
so critical are things like the extrinsic incubation period. We
don't really know what that is. We don't know its temperature
dependency. We do have some work that's going on in one of my
collaborator's labs to identify that. And some other issues are
really understanding the social side. So there are absolutely
different factors like poverty, vector-human interaction that
need to be incorporated into models in order to really predict
that risk.
Mr. Palmer. I want to move to another question. Mr. Parry,
we banned DDT, and by some estimates, there are 50 million
people who have died from mosquito-borne diseases, and just in
regard to the new science that we're trying to posit, what are
the odds and potential consequences of the offspring of Oxitec
genetically modified mosquitoes developing resistance or
tolerance to the self-limiting gene they acquire?
Mr. Parry. We haven't seen it. We've gone through over 200
generations now of our mosquito. We've seen no resistance
developing at all. There are certain biological issues and also
the way in which the technology is being done, so we're not
expecting to see it, but any scientist will say you'll never
say never.
I think the issue is, what does our product actually do. It
stops the mosquito from breeding. So what happens if it doesn't
work? Well, then the mosquito can breed, so it becomes a normal
mosquito.
Mr. Palmer. Well----
Mr. Parry. So effectively we would stop releasing.
Mr. Palmer. Looking at the situation from another angle, is
there any chance that the Oxitec technology might eradicate the
Aedes aegypti breed of mosquitoes?
Mr. Parry. Mosquitoes only fly about 200 yards in their
lifetime, so actually the effect when you're releasing our
mosquito is in the area in which you're releasing it. So you
actually have to be very deliberate about where you go, how you
control it, and against all of the issues you've raised, we
have the marker. We have something that no one's ever had,
which is the ability to track and trace exactly what we're
doing so we pick up that metric all the time.
Mr. Palmer. Well, I'm out of time. My last question is, one
of our colleagues on the Committee talked about CO2
as a marker apparently in the context of climate issues. Is it
any of your recommendations that we breathe less?
I yield back.
Chairman Smith. Thank you, Mr. Palmer.
The gentleman from New York, Mr. Tonko, is recognized.
Mr. Tonko. Thank you, Mr. Chair, and welcome to all of our
experts for very valuable information.
Dr. Ernst, in your testimony, you discussed community-based
surveillance activities including USDA's efforts to encourage
participation by community members. There's no doubt that we
need to invest more resources into surveillance. In particular,
I'm encouraged by efforts to use crowdsourcing and citizen
science methods within the Federal Government to advance and
accelerated scientific research and literacy. One example of
this is USDA's Invasive Mosquito Project, the IMP, which was
launched recently as an initiative that pairs high school
teachers and students with mosquito control and public health
professionals. This partnered citizen science classroom project
helps high school teachers meet the next-generation science
standards and students learn about mosquitoes, public health,
and safety. The project is aimed at monitoring invasive
container inhabiting mosquito species across the United States.
According to the project's description, by doing this
monitoring, we can determine where the invasive mosquito
species as well as the native species are distributed across
the United States and define at-risk human and animal
populations based on this distribution.
With all of that said, can you speak more about why
projects like these can help with surveillance efforts as well
as providing enhanced public education?
Ms. Ernst. Sure. So I think that these kinds of projects
are great for a number of reasons. We've carried off some of
these in Arizona specifically as well. We developed something
called the Great Arizona Mosquito Hunt, and that engaged high
school students to set out the ova position cups, which is a
fairly sensitive measure of detecting whether or not there are
mosquitoes present or not, and it allowed them to go through an
educational module to teach them about the mosquitoes.
So I think these kinds of efforts not only can be broadly
disseminated to a large group of people but it's also targeting
young children as well as teachers who can pass that
information on to their parents and really help be vigilant
about mosquito control within their own household.
I think that there is some things that need to be ensured
for these kinds of projects including standardization of the
methods to ensure that when you do get a negative that it is
because there is not a mosquito around. That's one of the
things that's difficult to determine. We found a lot of
negatives in the high schools where we placed traps in part
because, as the gentlemen have said previously, it doesn't fly
very far and school grounds are generally kept pretty clean. So
really understanding some strategies to standardize this
process to yield the best success are also important.
Mr. Tonko. Thank you. And to you also Dr. Ernst, in reading
testimony for today, I was struck by how we do not have a good
idea of where the mosquito that transmits the Zika virus lives.
You have done research into modeling the geographic areas with
higher potential risk for local Zika transmission. Can you
please describe that study and how forecasting studies like
yours could help decide where to invest our resources?
Ms. Ernst. Sure. So this was sort of a first cut, I think
is what we basically have been stating, in trying to understand
where the Aedes aegypti might be present in the United States
as well as the seasonality of the vector, and it really is
based upon what we know about the dynamics of the mosquito and
how it relates to climate and weather. So most of the stages of
the mosquito are sensitive to temperature as well as
precipitation for the aquatic stages of the mosquito so we can
leverage information on sort of average--what we did was, we
took average ten years. worth of data to look at if you had the
weather that's sort of typical in these cities, when would you
see Aedes aegypti abundance, and then we compared that to an
area where we know there's fairly good conditions. We compared
it to the numbers that we had in Miami. And so the map that we
actually depict is relative abundance, so it's relative to sort
of the high season in one of the most climatically suitable
places, and we look to see how different that might be for the
other 49 cities that were mapped and modeled.
I'm sorry. I can't remember the second part of your
question.
Mr. Tonko. Well, it was just how we could best use that
information to decide where to invest resources.
Ms. Ernst. Right. So, you know, some of the other layers
that we have incorporated are related to travel introduction.
So obviously without any local transmission at this point, it
would have to come from somebody who had traveled outside the
country and brought back the virus. And then as well needing to
understand poverty and other factors that might facilitate more
vector-human interaction.
Some of the things that you can use the data that we
presented for are understanding when theoretically you're going
to have a higher peak of mosquito activity within your
jurisdiction if you're on the map as well as trying to look to
see, has your jurisdiction actually had dengue or chikungunya
in the past. That's another piece that we mapped into that
study.
Mr. Tonko. Thank you very much. I sense, Mr. Chair, that
there's a degree of urgency to invest here and invest wisely
and deeply into this program.
If I might take the liberty, today is an opportunity for
foster youth to shadow individual legislators, and if I might
introduce right behind Congresswoman Clark, we have Steven
Fallon, who is my shadow today as a foster youth, if you'll
recognize Steven, please.
Chairman Smith. Thank you, Mr. Tonko, and the gentleman
from Michigan, Mr. Moolenaar, is recognized for his questions.
Mr. Moolenaar. Thank you, Mr. Chairman.
Dr. Ernst, in your testimony you identified some of the
knowledge gap areas about the interaction between the Zika
virus and the mosquito that spreads it.
I was also curious, Dr. Neafsey, the work you're doing to
sequence and map the genome, is that going to help fill in some
of the gaps in knowledge, and kind of where are we in that
process, timelines, those kinds of things?
Dr. Neafsey. Sure. So I think I can attest to the value
that genome sequences can have as a resource for informing
precisely the kinds of parameters that make the types of models
Dr. Ernst described accurate. In the malaria field, we've been
using this kind of data to inform models of malaria
transmission and malaria distribution. One example of the way
these data can be used is a study that was published last year
by investigators at Notre Dame, who did genetic profiling of
Aedes mosquitoes from the Capitol Hill neighborhood, and used
the genetic signature of these mosquito samples over the course
of several years to determine that this was a year-round
population, likely a year-round population, taking refuge in
sewers and below ground during the cold winter months rather
than a new population that was being refounded by genetically
different sources with every successive warm season. So this is
a small example of some of the resolution that DNA-based data
can lend to some of the parameters that are useful for
understanding the existing and maybe the prospective
distribution of mosquitoes.
Mr. Moolenaar. I was reading a little bit about you're kind
of communicating via Twitter and periodically getting together,
like kind of work projects in place, and how do you monitor
who's doing what and----
Dr. Neafsey. So Twitter is a fantastic scientific resource.
I don't know if it's recognized outside of the scientific
community but news travels so quickly. It is unparalleled for
organizing people who are like-minded and who want to get
behind a common cause.
So Twitter, I think, and a lament about the quality of the
existing Aedes mosquito genome map was the genesis of this
working group I alluded to. Since then we've had phone
conversations, emails, but as yet no in-person meeting. As I
mentioned, this is kind of a volunteer group, and we've been
working catch as catch can to this point.
Mr. Moolenaar. I know you don't want to commit to a
timetable of when, you know, the completion of the assembly of
the DNA map but can you give us a rough ballpark?
Dr. Neafsey. I can say that we have efforts, parallel
efforts, underway using several different new technologies that
we hope will yield a better genome map on the order of a month
or two. These are unproven but we're very optimistic given
their performance with sequencing human genomes and assembling
maps for human DNA. So I think we're optimistic that we won't
have a perfect genome map by this fall but we will have a map
that is significantly improved beyond the existing one.
Mr. Moolenaar. Thank you very much. I yield back, Mr.
Chairman.
Chairman Smith. Thank you, Mr. Moolenaar.
And the gentlewoman from Massachusetts, Ms. Clark, is
recognized.
Ms. Clark. Thank you, Mr. Chairman, and thanks to all the
panelists, especially Dr. Ernst, thank you for making your
decision to skip that milestone. We appreciate the information
that you all are bringing to us today.
I wanted to start with something very specific and sort of
move to the more general. The impact of this virus on a fetus
is one of the most frightening aspects of a rapidly changing
landscape but do we know now exactly how the virus causes birth
defects like microcephaly and do we have an understanding of
how exposure at different times of pregnancy can impact the
fetus, or is this a gap in our research?
Mr. Neafsey. I don't think we have a virologist on the
panel but I'm going to step slightly outside my comfort zone
just to provide a basic answer and say that, you know, the
general principles that determine what cells and what hosts a
virus can infect often come down to the particular proteins or
other attributes that are on the surface of those cells. The
virus usually needs to recognize a doorway and be able to
interact with it in a way that permits entry.
So some of the work that's been done to date has taken
advantage of some of these fantastic new resources in a
laboratory such as these brain organoids, very simple, very
small, three-dimensional tissue replicas of what a developing
brain might look like and the realization that that has led to
is that there are, you know, particular cells at stages of
brain development that are indeed susceptible to Zika
infection. I think there's much work to be done to understand,
as I mentioned previously, the spectrum of cell types that
could be susceptible to Zika infection and the precise proteins
and sort of molecular interplay that's responsible for Zika's
ability to infect the cell types and the range of organisms
that it does infect on the host side as well as, let me say,
the mosquito side. Its ability to proliferate within mosquitoes
and be injected into people that are bitten subsequently is
another aspect of the molecular biology that I think we need to
determine.
Ms. Clark. Dr. Presley?
Mr. Presley. If I could add, ma'am, there is so little
known right now about how the Zika virus interacts in the body
because we all looked at each other and shook our heads.
Ms. Clark. Right.
Mr. Presley. You know, something to consider, and it's
another area that we're going to have to find out about is, you
know, you may not be able to find it in a person's blood after
they've recovered. A week or so after being viremic, you might
not be able to find it in the blood, but they're finding it in
semen 60 days after recovery or no more symptoms. The virus is
going somewhere, hiding somewhere. There's a lot of viruses
that do that, whether it's deep organ or whatever. I think
there's a lot to learn. I think we can agree on that.
Ms. Clark. And I think that brings me to a more general
point that may be even harder to answer, especially in under 2
minutes, but as we have a discussion about how we react as
Congress and in funding and when we get into pandemic mode, do
we not make the most efficient choices, but here we are with
this very frightening virus that is only one potential just
mosquito-borne virus that has changed very quickly, spread very
quickly around the globe and now in the United States, and we
have very little understanding, and as I listened to your
answers with the need for diagnostics, looking at resistance,
mosquito control, dealing with issues of social behavior,
private property, how we balance those, also looking at
vaccines, understanding the genome, on and on, how do we
approach these? And I have some concerns about the way we have
funded our response by taking it from funding from other
important diseases, and what is the better way?
One of the most terrifying conversations I ever had was at
the Broad looking at antibiotic resistance and infections, so
how can we do a better job of funding basic science that allows
you to do the applied science that can bring us some answers in
22 seconds?
Mr. Neafsey. I can speak briefly. I think what's important
is to set up an infrastructure for collecting and pooling
information. I think there are a lot of investigators
collecting diverse forms of information, and I think there are
opportunities to really rapidly advance our state of knowledge
about Zika and other emerging epidemics on the horizon by
organizing that information, creating communication channels,
not just exclusively via Twitter but other media, and making
sure that we are performing surveillance, that we're collecting
the kind of information we need to in the short term limit the
advance of these diseases and in the longer term understand
them so that we can develop longer-term control measures.
Ms. Clark. Thank you. I see I'm out of time. I yield back.
Chairman Smith. Thank you, Ms. Clark.
The gentleman from California, Mr. Swalwell, is recognized.
Mr. Swalwell. Thank you, Chair. Thank you to our panelists.
People at home are terrified about Zika, and for good
reason. I've gone across the country with a group called Future
Forum. It's 18 of the youngest members of our Democratic
Caucus, and we've engaged with thousands of Millennials, young
people who already are having financial difficulties, starting
a family, and now I think Zika, from what we've heard, is an
additional just health difficulty that has been posed as far as
when it comes to travel and planning, for starting a family.
So my first question in light of that, does anyone on the
panel disagree with the science behind the President's request
for $1.9 billion for addressing this crisis?
Seeing that no one has answered, is anyone familiar with
Ronald Klain's opinion piece in the Washington Post this
weekend, ``Zika is coming but we're far from ready''? Has
everyone read that piece? In that thoughtful piece, Mr. Klain
points out that the funding approved in the House for the
Ebola--taking money from the Ebola crisis to address the Zika
crisis is like sending all the fire trucks from one city to
help fight a blaze in another. It's short-sighted and
dangerous. He also suggests that we should look at--to plan for
future crisis like this having a public health emergency
management agency. Any thoughts from any of the panelists as
far as having a separate agency similar to FEMA but focused on
public health emergencies? Yes, Dr. Presley?
Mr. Presley. I think one of the situations--and I don't
know about California but Texas is a home-rule state, so
everything--every emergency is handled at the local level until
other support is needed, and this is mainly to your last
comment. Making another federal agency to funnel down money and
hope that a little bit finally gets to the bottom on the
ground, I do not think works. I think that's part of the
problem now is we don't have the on-the--the boots-on-the-
ground support that's needed.
Mr. Swalwell. Yes, Dr. Ernst?
Ms. Ernst. I'd just like to echo that. I also think that,
you know, maybe something within one of the existing agencies,
for example, the Centers for Disease Control, which has been
leading a lot of the response in Puerto Rico, for example, but
I also think trying to figure out a way where we can leverage
other resources besides federal or state employees to respond
would also be something that's useful. You know, every time
that there's a crisis, there's a lot of volunteers, physicians
and nurses and public health professionals who want to help,
and we don't really have a good infrastructure in which they
can be trained and deployed to help in these emergency
situations. And so I think having some sort of infrastructure
where people like myself and maybe some of the other panelists
could use their expertise to help in the response would be
really beneficial.
Mr. Swalwell. Great. Thank you. And my perspective is that
people at home and across the country, they don't care whether
it's a Republican solution or a Democratic solution that solves
this; they just want to see government act in a crisis and get
it solved.
So thank you, Chairman. I yield back.
Chairman Smith. Thank you, Mr. Swalwell.
And the gentlewoman from Maryland, Ms. Edwards, is
recognized for her questions.
Ms. Edwards. Thank you, Mr. Chairman, and thank you very
much to the witnesses today. I really appreciate your
testimony.
Just a few weeks ago--I'm the Co-Chair of our Democratic
Steering and Policy Committee--we held a hearing with Dr.
Fauci, the Centers for Disease Control, the American Public
Health Services, a mayor or so, about Zika, and one of the
things that surprised me because I didn't know very much in
looking at the maps, both the maps that we have here today but
also other maps showing where the spheres of outbreaks are
going to occur, it's pretty daunting, and especially if you
look through the Gulf states, the South, and the Mid-Atlantic
region.
And so my question actually has to do with the spread
because although I understand there's a particular type of
mosquito, I was surprised to know, and maybe I'm wrong about
this, that whether the Aedes aegypti--is that how you pronounce
it?--mosquito, once it transmits to a human host, then can
another mosquito, the traditionally found Asian tiger mosquito
in the East, then transmit infected blood to another human
being, or is that something that we know? Because to me, that
suggests that we have just, you know, much more potentially
out-of-control circumstance. And I recognize there are a lot of
things that we don't know, and this is tied to how we need to
think about things like insecticide resistance and whether we
then have the capacity for the boots on the ground to have the
resources that they need to be able to respond should there--
which I presume there will be a much wider spread or outbreak.
If anybody has any thoughts on that, I'd appreciate it.
Mr. Presley. On the transmission, if Aedes aegypti or Aedes
albopictus--you mentioned the Asian tiger mosquito--it's not
the blood, the infected blood, that they're moving. Dr. Ernst
has talked about extrinsic incubation, and that's once the
mosquito picks up that virus, that virus has to move through
the mosquito's body into the salivary glands, where it can
replicate, the traditional model. And so there's a period of
time, up to a week, more information's needed. So it's not like
the mosquito can feed on the person and immediately go bite
another person and be infected.
Ms. Edwards. But then--I mean, the question gets--that I
have is, does it really matter what type of mosquito then?
Mr. Parry. Yes, it does. In this respect, Aedes aegypti,
the way to think about it is, Aedes aegypti is public enemy
number one responsible for far and away the greatest level of
disease transmission, whether it's dengue or chikungunya and
now actually Zika. So Aedes albopictus is a species which
actually in its behavior it's quite aggressive. It's a nasty
biter, worse actually then aegypti. You notice it worse. The
bite is worse. But actually it's a very inefficient disease
vector. So in an ideal world, one would tackle both, but if
you're looking at disease transmission and how to make an
impact, tackle Aedes aegypti.
Ms. Edwards. Got it.
And then if you could talk again about the incubation
period, because I think part of the testimony that we've heard
both here and today is, we don't know a lot about the
incubation period, but there's a potential especially if
there's a transmission through sexual contact that the
incubation period could actually be much longer. So you might--
one might, for example, in terms of public health advice,
advise a woman who is of childbearing age that there could
potentially be a year and a half during which you really should
not engage in sexual contact. Is that true?
Ms. Ernst. Well, I think we don't really know exactly yet
how long the virus can persist in semen. As Dr. Presley was
saying, there has been some evidence up to 3 months after the
infection was thought to occur. I would suggest that if
possible--I know that the resources are really difficult--to
follow up each individual man until he screens negative, but
that's one potential possibility. The other possibility is that
we do have some research that's ongoing that I have heard of
that they are following cohorts of men who are return travelers
to really identify what is sort of that average time frame in
which they can harbor the virus in their semen.
Ms. Edwards. I guess, you know, if there's 3 months and
then add to that a 9-month pregnancy, that is a long window of
time, and so I think it begs the question of how it is that
we're advising people of childbearing age who've traveled to
those regions what they need to think about. I leave it at
that.
Chairman Smith. Thank you, Ms. Edwards.
That concludes our hearing today. We thank you for your
expert testimony. This has been one of the more interesting
hearings that we've had. You all are experts in certain areas
and all of those areas were of interest to members of the
Committee today. So thank you all again. We may be back in
touch, and I should also say that members have two weeks to
submit questions to you all. You heard the comments today, how
many questions went unanswered, so you may get some more
questions in the next couple of weeks.
Thank you all again, and we stand adjourned.
[Whereupon, at 12:15 p.m., the Committee was adjourned.]
Appendix I
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Answers to Post-Hearing Questions
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