After Miami-Dade County reported the first four cases of locally transmitted Zika in the United States last week, cities around the country are preparing for outbreaks of Zika, the mosquito-borne disease that produces fevers and has been linked to microcephaly and other birth defects in Latin America and the Caribbean.
Fom New York to Los Angeles, urban areas are in danger of outbreaks because the Aedes aegypti mosquitoes which carry the virus spread during the hot summer months.
But in few cities has the debate about possible solutions grown so heated as in Key West, a community of 25,000 people on the southern tip of the Florida Keys. Despite strong opposition from some residents, authorities there are considering the use of genetically modified mosquitoes to reduce the Aedes aegypti population.
The method has been endorsed by many scientists, and the U.S. Food and Drug Administration reported in May that it would not have any “significant environmental impact on the Keys.”
Opposition from residents has complicated the process and raised important questions: Must community leaders always obey residents' wishes? Or should the priority be to protect people from danger, regardless of their complaints?
The proposal and its opponents
Officials have proposed a test in the Key Haven neighborhood by Oxitec, a British biotechnology company linked to Oxford University that has carried out similar tests in parts of Brazil, Panama and the Cayman Islands. Company scientist Darrid Nimmo says those tests reduced the population of dangerous mosquitoes by 90 percent.
Oxitec created a variety of the Aedes aegypti with a gene that prevents offspring from surviving. Mosquitoes are bred in laboratories and the males are released to mate in the wild. But their offspring die before adulthood, drastically reducing the mosquito population in the test area.
The Key West test would be Oxitec's first in the United States, and would be carried out free as an evaluation, said Beth Ransom, a spokesperson for the Florida Keys Mosquito Control District (FKMCD).
Key West has been trying to hire Oxitec since a 2010 an outbreak of dengue, a disease also carried by the Aedes aegypti mosquito. But residents have been fighting the proposal long before Zika became a risk.
Key West real state agent Mila de Mier has become the face of the opposition, running an online petition against the test that has been signed by more than 168,000 people in about four years.
The overwhelming majority of the signers, however, are not Key West residents, said Michael Doyle, executive director of the FKMCD. “The last time we checked, 85 percent of the signers did not live in Florida,” he said.
A poll published by researchers at Johns Hopkins University in May showed 58 percent of Key Haven residents opposed the project, although only 22 percent of the about 1,000 residents in the area responded. The poll was taken before Zika started to make U.S. headlines.
De Mier said Doyle and others at the FKMCD are trying to dismiss her petition and residents' concerns.
“I am not anti-GMO, a vegetarian or an activist,” she said. (GMOs are genetically modified organisms.) “I was a nurse. When all this started, I said, 'This looks like a good idea.' But then I went to meetings with Oxitec, and the more I asked the more uncomfortable I felt."
She complained the company changed its story over the years. “First, they said that one out of every 1,500 males released turn out to be females. Now they say it's one in 10,000. Which is it?” said de Mier. Only females bite humans and spread the Zika virus.
Nimmo said the company's method of separating males and females is precise but imperfect. In 2012, it was indeed one in 1,500, he added, but the Panama test allowed the company to reduce the number to one in 10,000. What's more, he added, it's been proven that the genetically modified female mosquito bite is no different from that of a wild mosquito.
De Mier also says that 3 to 4 percent of the mosquito offspring with the modified gene manage to survive in the laboratory. Nimmo said that's true, but it's never been known to happen in the real world, where survival is much harder. Even if a few mosquitoes survive, he added, they do manage to reduce the overall population.
The risk for cities
Just last week, Miami-Dade County recorded the first cases of locally transmitted Zika in the United States – meaning the first infected mosquitoes in the country.
It could be a matter of time before the disease spreads rapidly to other parts of Florida and the United States. Oxitec's mosquitoes may help, but the potential solution faces strong opposition.
“People must give their consent. Without consent for the experiment, Oxitec should go away,” said de Mier. “Why does the municipal government want to experiment with biotechnology on me and my family, against my will?”
Key West residents will vote on the Key Haven test project in November. The result will not be binding, but three of the five city commissioners – including the one that represents the Key Haven area – have promised to follow the voters' wishes.
But if they vote against the genetically modified mosquitoes, they would leave the residents largely unprotected from the Zika virus. What should cities do? South Miami Mayor Philip Stoddard, whose community could eventually be affected by the virus, said the issue is complex.
“The truth is that if you ignore your constituents, they will vote you out. It's indeed important to have them on your side when you do something," said Stoddard, who teaches biology at Florida International University. “But at the same time, some people are totally resistant to information, and they hate anything GMO. For them, perhaps you will have to wait for the disease to come. And then they will change their minds.”
No other method is as effective as Oxitec promises, and insecticides and pesticides damage the environment, Stoddard added. What's more, using too much insecticide on mosquitoes may allow them to develop an immunity.
Stoddard acknowledged a problem with Oxitec's modified mosquitoes: deploying them in large cities could be very expensive, he said. But perhaps the arrival of Zika may lead voters to justify this “luxury.”
“I am completely in favor of using this method,” said the mayor. “Oxitec has done all the necessary tests to prove it works and is safe. But people will never be satisfied. That makes no sense.”