Genetically modified mosquitoes set off uproar in Florida
November 9, 2013 8:00AM ET
Potential solution to outbreaks of dengue fever, other mosquito-borne
diseases awaits FDA approval
[log in to unmask]" width=960 height=600 alt="Oxitec's dye-marked Oxi513A male mosquitoes ready for release i">
Oxitec's dye-marked Oxi513A male mosquitoes ready for
release in Brazil.Courtesy Oxitec Ltd.
KEY WEST, Fla. In late October, the U.S. Navy and U.S.
Department of Agriculture tested insecticidal aerial spraying techniques
over a warfare range in Jacksonville, Fla. The purpose: to evaluate how
to lower populations of the blood-feeding Aedes aegypti mosquito, which
transmits dengue fever.
Farther south, on the Treasure Coast, Florida health officials had a busy
summer trying to control the most recent dengue fever outbreak. Some 22
people contracted the disease, known as break-bone fever for its
debilitating joint pain and severe flu-like symptoms.
"It's very difficult to spray everywhere where this mosquito hides
and breeds," said Gene Lemire, director of Martin County Mosquito
Control. "It's very sneaky."
Officials admit they are having mixed results with conventional methods,
such as fumigations and aerial spraying. The mosquito is tough to hunt
down. It thrives in tropical metropolitan areas, moves indoors and can
hide in closets, even in folds of laundry.
It's something most people agree is a problem. But a different and
controversial potential solution is splitting communities in the Sunshine
Michael Doyle is director of the Florida Keys Mosquito Control District
(FKMCD). His job is to keep the 44 inhabited islands of the total 1,200
that spread across the Florida Straits free from Aedes aegypti
mosquitoes. He wants to release genetically modified (GM) male
mosquitoes, specifically designed to pass down a suicide gene that kills
their own offspring, into the wild in hopes of bringing down the
dangerous dengue-carrying mosquito population and preventing new
"We have tried everything from chemical fumigations to parasitic
nematodes, dragonflies, everything you could think of," Doyle said.
Last summer the agency deployed a 2-pound drone, hoping the aircraft
could help spot potential water breeding grounds in remote
"We're in an area with a year-round Aedes aegypti population,"
Doyle said. "We need to reduce the mosquito population to low, low
levels so that transmission of dengue is impossible."
The infected female Aedes aegypti mosquito is the only one that bites and
can transmit the dengue virus, along with other infectious diseases such
as yellow fever and Chikungunya fever. The strategy has been to wipe out
as many dengue vectors as possible to prevent the disease from taking
hold in the human population.
But it may already be too late. Although dengue is considered rare in the
U.S., some experts believe the recent cases in Florida are signaling the
tip of the iceberg in terms of future outbreaks.
Effective abroadIn recent years, there has been a
dramatic increase in dengue fever worldwide. It is estimated to infect
from 50 million to 100 million people in metropolitan tropical
In the U.S., probably no place is more vulnerable to a dengue outbreak
than the Florida Keys, where the Aedes aegypti mosquito has been an
invasive pest since the 16th century.
Yet when residents found out the mosquito control district was working
with Oxitec, a British bioengineering company, to release hundreds of
thousands of GM mosquitoes in their town, they were outraged.
Doyle explained that only male mosquitoes were altered, and they do not
bite, so therefore they could not transmit diseases. Still, visions of
mutant mosquitoes' offspring that could survive and change a delicate
ecosystem were rampant among residents.
Mila de Mier, a Key West real estate agent, started a petition last year
opposing the GM mosquitoes. She has collected more than 125,000
"I'm all for the experiment, but it has to be safe," de Mier
said. "Why can't we have independent, peer-reviewed research to
I wish we could get away from the chemicals, but I'd rather stick with
that until we know for certain what the long-term impact of those GM
mosquitoes could be.
In 2009, Oxitec released 3.3 million GM mosquitoes in the Cayman Islands
and published its
results detailing a more than 80 percent mortality rate for
mosquitoes in its test sites. The altered male insects passed down a
lethal gene that, when inherited by their offspring, served as a death
sentence for the progeny before adulthood. That experiment was criticized
by organizations worldwide for being conducted without public
consultation and independent oversight. Despite the uproar from
environmental groups, Oxitec expanded its operations to Malaysia and
This year, Brazil announced it was in the throes of an official dengue
epidemic. Now a second, more ambitious collaboration with Oxitec is in
the "ramp-up" stage of building a "mosquito plant" in
the state of Bahia. Eventually, 4 million altered male mosquitoes will be
Biologist Margareth Capurro of Sao Paulo University is heading the second
collaborative project with Oxitec and the Brazilian government. She said
she knows that people were suspicious of Oxitec because it is a
for-profit company, but she will have the independence to assess the
experiments on her own.
"We have an agreement with Oxitec that I will evaluate the product
independently," Capurro said. "Is this the best that scientists
can provide for this technology? No. The science is good, but we can
improve things by finding ways to bring down the costs."
Residents reactBut far from the tropical city of
Jacobina, Brazil, many Key West residents remain unconvinced that GM
mosquitoes won't survive and cause unknown problems. There hasn't been a
dengue outbreak in three years on the tiny island, so opponents wonder,
why take the risk?
"Why not keep with the status quo and have more time for more
studies?" de Mier said.
But Doyle, of the mosquito control district, says residents are not doing
enough on their own to protect against mosquito proliferation.
"Unfortunately, when we go out to inspections we are continuously
finding many containers with rainwater, and people aren't being careful
to empty them," Doyle said. "It's just not on people's mind to
empty containers with water or to use mosquito repellent."
[log in to unmask]" width=350 height=218 alt="Oxitec's Derric Nimmo; genetically modified mosquito opponents">
Why can't we be friends? From left, Oxitec's Derric Nimmo;
Joel Biddle and Mila de Mier, opponents of genetically modified
mosquitoes; and Michael Doyle, director of the Florida Keys Mosquito
Control District, after a community meeting. Patricia Sagastume for Al
Joel Biddle was one of the Florida patients who contracted dengue
in the 2010 outbreak. He admits he rarely uses repellent, but he does
avoid standing near bromeliads after a rainstorm.
"I wish we could get away from the chemicals, but I'd rather stick
with that until we know for certain what the long-term impact of those GM
mosquitoes could be," Biddle said. "It seems Oxitec is rushing
to release something that hasn't been adequately tested
But Oxitec says it can trace the mutant gene in the wild. Each GM insect
is inserted with a fluorescent marker in the altered gene. It then
becomes easily visible to the naked eye when the mutant gene is inherited
in the offspring.
"As soon as we stopped releasing the mosquitoes, within two weeks,
as we predicted, there is nothing in the environment that is left because
males mate with the females and then they die; and their offspring is
gone, too," said Derric Nimmo, director of Oxitec Public Health
Still, some object to Oxitec's secretive research methods.
"Oxitec didn't do themselves any justice by doing things
clandestinely in Cayman," said Phil Lounibos, distinguished
professor at the University of Florida's Florida Medical Entomology
Laboratory. "If we can believe their evidence, and if the goal is to
reduce the risk of dengue, can the GM mosquitoes reduce the native number
of vectors to reduce the risk of dengue?"
"Yes, absolutely," said Capurro, the Brazilian researcher.
"No one knows at what level the population of the mosquitoes must be
to ensure dengue can't be transmitted. In the first trials, we saw a
decrease in the mosquito population by 90 percent in two test districts,
and that's very good."
Changing courseAnthony James, a distinguished professor
at the University of California, Irvine, has researched the international
regulatory process of GM mosquitoes and advises the Food and Drug
Administration (FDA). James said that as bioengineering technology
advances worldwide, more ground rules are needed in host countries to
regulate GM insects.
"The science is really good, but I never would have done it like it
was (done) in Florida," he said. "First, community engagement
is very specific to each region, and what works in Brazil won't be the
same in Florida. Another problem is, the U.S. is a patchwork of people,
and nobody wants to take primary responsibility for regulating
But if mistakes were made by not informing the Key West residents sooner,
Doyle said the mosquito control district is paying attention now. Last
year, the Key West City Commission passed a resolution objecting to the
release of GM mosquitoes in the town until more research is
Doyle said he listened to the complaints and changed the trial site to
Key Haven and Stock Island, two areas outside Key West with high Aedes
aegypti populations. But instead of pacifying opponents, the move had the
"Stock Island has a large immigrant community, with trailer homes
and not a lot of English speakers," said de Mier, the activist.
"Key Haven homes are spread out, expensive and more isolated. It
seems the mosquito people just want to find a place where they won't have
a lot of protesters."
"This is safe, and it's been proven," Doyle said. "In
terms of allergenicity and health issues, the FDA is looking into that,
so I put it in their hands."
At a recent community meeting, when de Mier relayed her story of how she
went twice to the Washington offices of the FDA to deliver her petitions
in person, she received cheers from the audience. The first time, she
said, the FDA destroyed her documents.
"The FDA people said they shredded my petitions because they thought
the box they were in contained real GM mosquitoes, so the next time I
went I had even more signatures," de Mier told the crowd. The
anti-FDA sentiment in the room was palpable.
But the residents weren't the only ones frustrated with the
"We want people to trust we're doing it right," said Oxitec's
Nimmo. "We've been talking to the FDA, quite frankly, telling them
here's the information about our technology, here's how it works, how are
we going to regulate this?"
'Watching every move'At the beginning of the year, the
Florida Keys Mosquito Control District conducted informal surveys and
hired an independent outfit to
attitudes of Keys residents. In some answers, more than half the
respondents supported GM technology to control mosquitoes.
"I don't think the survey means much, because if you ask people if
they want GM mosquitoes in their neighborhood, they will say no," de
Mier said. "Before, people didn't know DDT was bad and we used that
to kill mosquitoes. A lot of people just don't trust the FDA and this
private company to tell us the truth, because we don't know what the
long-term effects are yet."
But whether the technology will get off the ground in the Keys will
depend on the FDA decision, Doyle said. He has assured residents he won't
proceed without the agency's approval.
"Technically, I think he can do it without their approval, but if
the mosquito people do go on with this, we have an attorney and we will
ask who will take responsibility if something goes wrong," de Mier
said. "We're going to be watching every move they make."