Florida’s Feud Over Zika-Fighting Mosquitoes Heats Up
October 10, 2016 in News by RBN Staff
via: Bloomburg
On a Tuesday morning in September, under a sweltering tropical sun on the island of Grand Cayman, 140,000 mosquitoes flit around in four large coolers in the back of a gray Toyota minivan. Behind the wheel is Renaud Lacroix, a Ph.D. in biology and medical entomology who works for the British biotechnology company Oxitec. A colleague, Isavella Evangelou, crouches behind him in a tight space next to the coolers. The minivan is idling on the side of a dirt road in West Bay, a quiet neighborhood where iguanas and roosters dart in and out of the yards of small homes painted in Caribbean pastels. The time has come for the mosquitoes to fulfill the purpose for which they were genetically engineered: a kamikaze mission to eliminate their own species.
As the minivan’s air conditioning struggles against the humidity, the two Oxitec scientists prepare for the release—a process that, given the Island of Dr. Moreau–level hysteria that sometimes greets Oxitec’s efforts in test sites around the world, is surprisingly low-tech. First, Evangelou pulls out a piece of light sheet metal that’s been shaped into a foot-wide tube. She sticks one end of the tube through a circular hole cut out of the van’s rear window, then fastens the other end in place with Velcro a few inches from the mouth of a small Dyson fan. Next, she takes her seat in the back, next to the fan, opens one of the coolers, and pulls out one of the 30 plastic containers in which the mosquitoes are waiting. Lacroix puts the van in gear, and off they go.
“Do I need to make a left here, Isavella?” Lacroix asks. Consulting a GPS-equipped tablet, she says yes. As the van slowly winds through the neighborhood, the tablet lets out a beep about every 30 meters. Each time she hears a beep, Evangelou—using little, if any, of the training that earned her a master’s in biology—gently lifts the lid of a plastic container, as close to the fan as she can, and several thousand mosquitoes are blown out through the metal tube and into the neighborhood.
It takes over two and half hours, emptying container after container, to release all the mosquitoes into West Bay. They’ve been doing this three times a week since July; residents used to grimace when they drove by, but now they barely glance over. The procedure seems more disruptive to those of us in the van. Each time Evangelou opens a container, a fair number of mosquitoes escape the wind tunnel and start buzzing around our heads. “There will be a few fliers, yeah,” Lacroix says with a smirk.
“A few” isn’t quite right. Before long, we’re overrun. Being in this van is like being in a Cheech and Chong movie, only with mosquitoes instead of smoke.
“Aren’t we going to get eaten alive?” I ask, trying not to sound too concerned.
“No,” Lacroix says. “They’re males.”
Male mosquitoes, he reminds me, aren’t the ones that bite. Just about the only thing male mosquitoes do, he says, is seek out females, which do the biting. Oxitec is trying to leverage this mating instinct to help wipe out one particular species of mosquito:Aedes aegypti, carrier and spreader of some of the worst insect-borne diseases known to medicine—dengue, malaria, and Zika. The A. aegypti mosquito has evolved to survive even the most effective pesticides. It can lay 500 eggs in just a bottle cap’s worth of water, and it prefers to bite humans over animals, so it lives in places where no one thinks to spray, like under the couch.
The idea behind Oxitec’s experiment is that if enough genetically modified male A. aegypti mosquitoes are released into the wild, they’ll track down large numbers of females in those hard-to-find places and mate with them. The eggs that result from any union with an Oxitec mosquito will carry a fatal genetic trait engineered into the father—a “kill switch,” geneticists call it. The next generation of A. aegypti mosquitoes will never survive past the larval stage, never fly, never bite, and never spread disease. No mosquitoes, no Zika.
Oxitec is far from the first company or research team that’s tried to sterilize an entire insect population. Scientists have been going after A. aegypti in this way since the 1970s, usually by irradiating them. The problem with radiation is that it makes the mosquitoes too weak to get out and breed. The great innovation of the Oxitec method is that it cleverly achieves the same result as sterilization, while leaving mosquitoes able to do what mosquitoes do.
The approach was developed by founder Luke Alphey, a British geneticist specializing in vector control, or the elimination of disease-bearing creatures. Oxitec has applied the method in Brazil, Malaysia, and Panama, often with partial support from the Bill & Melinda Gates Foundation, and claims to have reduced the A. aegypti population in tiny test areas by at least 90 percent. That’s a far better percentage than spraying, which usually hits about 50 percent and has a tendency to breed resistance, requiring more and more spraying to get the same low result.
“It takes one or two generations at least to be noticeable,” Lacroix says as he grabs a green fly swatter the size of a tennis racket and starts thwacking away at some of the mosquitoes flying around his head. A. aegypti’s life span ranges from two weeks to a month, so the company will know in a few months if the population is starting to decrease. If it is, Lacroix says, “we can roll out to the rest of the island, drawing down south through the peninsula.” Oxitec charges about $7.50 per person per year in each area it treats. While the price gets cheaper as the A. aegypti population decreases and fewer Oxitec mosquitoes need to be released, the treatments aren’t a short-term prospect: To ensure A. aegypti doesn’t come back, the company continues releasing its mosquitoes on an open-ended basis.
Chief Executive Officer Haydn Parry has called Oxitec’s method “a dead end” for the A. aegypti species. And, of course, in the age of Zika, such a dead end couldn’t be more desirable. Since the news emerged last spring that a spike in cases of microcephaly in Brazil appeared to have been caused by Zika, politicians and public-health officials from around the world have been beating a path to Oxitec’s door. U.S. officials were among them, even as Congress dithered all summer before finally, in late September, approving the funding of countermeasures to prevent large outbreaks. “I don’t think time is on our side,” Parry told a congressional committee in May. “I think the utmost urgency is required. I’ve just come from Puerto Rico, and we could have a catastrophe on our hands if we are not careful.” The big winner if Oxitec ends up enlisted to fight Zika in the U.S. would be Intrexon, a biotech company run by billionaire Randal Kirk, which acquired Oxitec for $160 million in the summer of 2015.
This August, the U.S. Food and Drug Administration approved Oxitec’s first stateside experiment, in Key Haven, Fla., an unincorporated area separated by a narrow stretch of water from Key West. In many respects, you couldn’t ask for a better test site in America. It’s secluded, tropical, and surrounded by water, which prevents new mosquitoes from entering the area. If the Oxitec method works in Key Haven, then Florida, and the country, could have a powerful tool to help stop an incipient public-health crisis.
There is, however, an obstacle. Oxitec has been trying to conduct a trial in the Keys for seven years, ever since a dengue outbreak there. Local opponents have thwarted those attempts for years, and now they’ve forced a pair of referendums, set for November, on the Key Haven test. Officials from the local Mosquito Control District have pledged to be guided by that vote—even if it means saying no to the FDA’s approved experiment, with a major Zika crisis looming over Florida. In public meetings, on local radio, and, of course, online, opponents have all but commandeered the conversation about mosquitoes and Zika in the Keys. They call Oxitec’s tactics unethical and underhanded. They call the company’s science untested, unproven, and unsafe. Above all, they’re worried about unintended consequences. Their not-so-affectionate name for the Oxitec mosquitoes: Frankenflies.
