GM Mosquitoes in Florida

Feb. 18, 2015, 1:52 p.m.

Hundreds of thousands of genetically modified mosquitoes may be released in Key Haven, Florida at a moment's notice. They are designed to wage war against Dengue fever, but many locals are opposed to the plan. Now experts and activists alike are questioning why the mosquitoes are coming in the first place and whether they're even safe.
(Photo : pixabay)

Hundreds of thousands of genetically modified mosquitoes may be released in Key Haven, Florida at a moment's notice. They are designed to wage war against Dengue fever, but many locals are opposed to the plan. Now experts and activists alike are questioning why the mosquitoes are coming in the first place and whether they're even safe.

The Dengue Details

With one third of the world's population living in affected regions, Dengue fever has quickly become a leading cause of illness and even death in the tropic and subtropics, according to the US Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO). Up to 100 million cases are reported yearly, but it is suspected that up to three times that number go unreported.

The virus was first identified in the 1950s, after a horrific epidemic of severe abdominal pain, vomiting, and hemorrhaging began to sweep across the Philippines and Thailand. It was identified as a mosquito transmitted virus, meaning that it can't jump from person to person. Even so, that hasn't stopped it from increasing the number of people it infects by 30-fold over the last 50 years. Today it affects Asian and Latin American countries in particular.

Recently, it has even found its way into the United States, with its most common vector, the yellow fever mosquito (Aedes aegypti), carrying the disease to 22 people in Florida state in 2009, and again to 28 people in 2013. Last year, only six local cases affected the state.

However, it's important to note that between 2006 and now, most other cases of the virus (affecting an average of 20-50 people a year) came not from local mosquitoes, but from bites received while abroad.

Comparatively, Brazil, El Salvador, Guatemala, Panama, and Venezuela all average a whopping 574,000 local cases annually, with more suspected to go unreported. (Scroll to read on...)

(Photo : EU Humanitarian Aid and Civil Protection/HPA, Laos, 2014) People in Laos drain an unused container of still water to help prevent breeding of Dengue carrying mosquitoes.

Mutant Mosquitoes to the Rescue?

Officials in Florida are now arguing that in order to keep Dengue out of the United States, they have to work to keep the mosquito down - namely by controlling population counts.

"Dump, drain, and cover" are words most Floridians are used to hearing side-by-side. Community action, such as simply ensuring that backyards have no still and shallow water around, has long been seen as an adequate control option, limiting the number of places that Ae. aegypti can breed. That, coupled with seasonal pesticide spraying, has reportedly been enough to keep a limited number of bloodsuckers in the sky.

However, the Mosquito Control District in Florida Keys (FKMCD) has expressed concerns that the mosquitoes are growing increasingly resistant to common insecticides, and past studies have shown thatAedes mosquito species are indeed capable of developing powerful resistances to the products the FKMCD uses year-round.

That's apparently why the district turned to British bio-firm Oxitec five years ago to start planning a new approach - one involving the use of genetically modified (GM) mosquitoes.

And while that certainly sounds frightening, it should be noted that Oxitec's approach is actually a decade old, having been put to use in countries like Brazil on a relatively large scale.

So How Does it Work?

Mosquitoes have an elegantly simple life cycle. Adult female mosquitoes are the only ones that actually bite and suck blood from mammals. Once adults, male mosquitoes only exist to do one thing - find a female, make babies, and die.

Adults of both genders don't even eat much, surviving simply off whatever energy they stored after viciously preying on microbial life such as larvae and the occasional flower nectar. The blood females suck, rather, is for their young. As the blood is digested, it serves as a source of protein essential for egg production, and those eggs only ever hatch after being fertilized by a male. (Scroll to read on...)

Size and antennae are the best ways to distinguish biting female mosquitoes from males.
(Photo : CC0) Size and antennae are the best ways to distinguish biting female mosquitoes from harmless males.

With this in mind, Oxitec's approach is easy to understand. By releasing thousands of sterilized males into a wild population, the hope is to "dilute" the breeding pool, pairing as many females as possible with unproductive males. These GM males still fertilize eggs, but thanks to a lab-made cocktail of lethal genes, their larvae will never make it to adulthood.

According to Oxitec, commercial trials of this approach have already resulted in success, with target populations declining between 92 and 99 percent in parts of Brazil and the Cayman Islands in the Caribbean.

However, it's important to note that because these modified mosquitoes never reproduce, the FKMCD will have to release them again and again. As things stand, the current plan calls for a release of 300,000 modified males per week for a period of up to 22 months. That's up to 26.4 million mutant mosquitoes flying around Florida.

And that's just in Key Haven, a small semi-secluded community about a mile east of the island Key West. Originally, decision makers had called for the experiment to encompass the whole of Key West, but the FDA quickly halted those plans, voicing concerns that the region was far too large for the first trial of an approach untested in the United States.

Feeling Like Guinea Pigs

Understandably, many Key Haven residents are not happy about these plans. US citizens are known to shy away from the idea of genetically modified anything, and when that thing could bite you there's bound to be some worry. (Scroll to read on...)

Even if someone were to be bitten, the firm assures citizens that "there's no difference between the bite of an Oxitec female and a wild one. You and your pet would have the same response to any bite (i.e. - itching, swelling etc)."

And since Oxitec's process only involves non-biting males, it's a virtual impossibility that a modified female would be around to do the deed.

However, "virtual" is a key word here. Past trials have actually shown that the occasional modified femaledoes indeed slip through, with 0.03 percent of all trial releases estimated to be female. If the same were to prove true for the Key Haven trial, a total of about 7,900 modified females could be out for blood.

That's one reason why nearly 150,000 US citizens have signed a petition calling for a stop to the trial, even as the plan awaits for FDA approval, which could happen as early as this spring.

"Why would we not expect GM insects, especially those that bite humans, to have unintended negative consequences?" asks Mila de Mier, a resident of the Keys who launched the petition back in 2012.

Three years later, with more information concerning the plan being explained in town hall meetings andinformational fliers, Nature World News reached out to Mier to find out if her opinion of the trial has changed.

She told us, if anything, she's more committed than ever to stopping the release.

"I've never been an activist! I'm a regular mother and business woman," she told us over the phone. "I'm busy, and yet I've taken up what feels like a full time job because I just can't stand to watch them launch an experiment without our consent - without our approval!"

According to Mier, her initial concerns were about the mosquitoes themselves and what kind of impact they could have on an environment in the long term, especially as the great majority of Oxitec trials only cite observations that last months, not years.

However, she stressed that these days, her aim has slightly changed. (Scroll to read on...)

Mier at FDA offices in Washington DC to personally deliver her petition a second time. The first time, the enveloped paper was reportedly thought to be a security threat and shredded.
(Photo : Mila De Mier) Mier at FDA offices in Washington DC to personally deliver her petition a second time. The first time, the enveloped paper was reportedly thought to be a security threat and shredded.

"The genetically modified mosquitoes is one thing, but this is about human rights now. We're getting to a point where we have almost 150,000 signatures. Of course a great many of them are not Key Haven residents, but they are potential visitors who may no longer come here!"

Past surveys conducted by the FKMCD have shown that about 60 percent of Key Haven's residents are "OK" with the release, with 10 to 20 percent set strongly against it. That's already not a stunning approval rating, and Mier argues that a lot of polled residents may just not know what the district is asking about.

"They're trying to sell this idea about isolation, but it's a residential neighborhood full of commuters," she added. "If I were to head up to a [Key Haven] elementary school and ask the parents who are dropping off their kids if they've heard about this release, I bet most of them are going to say 'no.'"

Since her petition passed the 100,000 signature mark, a threshold commonly recognized by the White House, Mier has even personally delivered multiple copies of it to the FDA's Washington, DC offices in the hopes of opening a dialogue with scientists and representatives.

Currently, she's even working with an attorney to see if the plan can be halted on legal grounds.

So What do the Scientists Say?

Interestingly, Mier's supporters aren't just other residents. While the Oxitec approach is a common control strategy, not everyone in the scientific community is thrilled about it either.

Phil Lounibos, an expert on insect ecology and behavior at the University of Florida's Medical Entomology Laboratory, recently told Nature World News that there is a "disconnect between mosquito control and disease control" that is rarely addressed.

"There is no 'threshold' of reduced mosquito numbers whereupon one can say there will be no Dengue transmission," he explained. "In Singapore, where mosquito control is rigidly enforced, Dengue remains common, in part because it is impossible to regulate the comings and goings of infected human carriers."

These carriers essentially serve as a delivery system, transmitting the virus to whichever mosquitoes that bite them regardless of how many insects are actually around. Even in small populations, the number of dengue-carrying mosquitoes could be high. (Scroll to read on...)

Yellow Fever mosquito - Aedes aegypti
(Photo : CDC - PHIL/James Gathany) Yellow Fever mosquito - Aedes aegypti

Just this February, the scientists at Gene Watch UK cited another pressing concern: the release of GM mosquitoes could spread antibiotic-resistant bacteria into the environment.

"Mass production of GM insects in factories, using antibiotics as an additive in their feed, could lead to drug resistance in bacteria, leading to the spread of superbugs as billions of insects are released into the environment in the future," warned Helen Wallace, GeneWatch UK's Director. "This important risk to human health has been ignored by regulators, despite bans on the use of antibiotics in animal feed in many countries."

report from the scientific watchdog group noted that Oxitec in particular breeds their mosquitoes and agricultural pests using the common antibiotic tetracycline, which can be found in the feed solutions for larvae. A consequence could be that the bacteria they naturally host are learning to resist antibiotics during this unnatural exposure.

A final argument against the release is what some experts call the "competitive displacement" problem. Nearly three decades ago, many Florida regions (but not the Keys) underwent an unexpected swap in mosquito species, where Ae. aegypti populations mysteriously dropped, while the infamous Asian tiger mosquito (Aedes albopictus) swelled in numbers. (Scroll to read on...)

Tiger mosquito - Aedes albopictus
(Photo : CDC/James Gathany) Tiger mosquito - Aedes albopictus

The concern is that the Oxitec approach may drive a similar change, especially if it lowers Aeaegyptipopulation counts by 80 percent or more. The tiger mosquito - another common vector of Dengue - could simply move in, rendering the estimated $1.1 million the FKMCD is prepared to spend on a Keys-wide project (about as much as they currently spend on spraying) money ill-spent.

A Time and Place for Everything

And that's what Mier and her supporters are arguing most strongly.

"Here's the deal... [the Keys] had no Dengue for half a decade, and before that it was 27 years before we saw a case. Why are we even talking about this?" she asked. "Let them experiment elsewhere - where the benefits outweigh the risks."

Mier told us she understands how Oxitec can almost seem like a God-send in some countries that are struggling with dengue on epidemic levels.

She even described how she attempted to reach out to the Minister of Health in Panama when she first learned Oxitec was working to launch trials there. A fluent Spanish speaker, Mier had planned to ensure that the region knew of the risks. However, after speaking with a stunningly accommodating aid for the Minister, she quickly realized something.

"[The aid said] 'ma'am, our people are dying, our kids are dying. I can get you an appointment within a day if there is any way you can help us with Dengue.' And I said 'I'll call you back.'"

"I realized that they were so desperate that they were willing to try anything. And I realized that this was not my place to be," Mier added, her voice cracking with emotion. "I realized that, to be honest, this is a good thing for them, to get the help they need as soon as possible."

And that's a refreshing opinion in a world where most people view things in black and white.

Nature World News also reached out the FKMCD to discuss the very gray nature of their plan and the mosquitoes in general, but we have yet to hear back from them.*

Still, it would only be fair to note that Michael Doyle, an entomologist who oversees the FKMCD, recentlytold NPR that he thinks a Dengue-free Florida is just a smoldering fire. The district, he says, is just looking to squash the brighter embers of a potential outbreak.

Whether GM mosquitoes are the right tool for that squashing, however, remains to be seen.

*UPDATE: The district has since contacted this reporter directly, but had nothing to add.

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