of millions of genetically modified mosquitoes in the Florida Keys. I realize that sentence

had a lot of scary buzzwords: mosquitoes, genetically modified, Florida. So, what's

the plan here, why are we doing this, and what are the potential risks?

Mosquitoes are more than just irritating pests that cause itchy bumps and make me dread going

outside. They are also considered the deadliest animals in the world. The diseases they carry

run the gamut from malaria to yellow fever, and their bites cause at least hundreds of

thousands of deaths each year. Sharks, by comparison, kill about 4 people annually.

One mosquito species in particular, Aedes aegypti, can spread several diseases like

dengue, zika, and yellow fever and is considered a serious threat to public health. So much

so that the Florida Keys Mosquito Control throws over $1 million dollars and six pesticide

spraying aircraft at them each year. Despite eating up about a tenth of their budget, these

efforts only reduce the Aedes aegypti population by 30 to 50%.

So, years ago the local government came to the conclusion that they couldn't go on

spraying their way out of trouble, and in 2012 they contacted the company Oxitec. At

the time, Oxitec was developing a genetically modified male Aedes aegypti mosquito designated

OX513A that would die before it reached adulthood – unless it developed in water containing

the antibiotic tetracycline. The thinking was if these males matured in a lab and were

then turned loose in the wild, they would mate and their offspring would inherit the

modified genes and die in antibiotic-free standing water when they hatched.

Starting in 2009, Oxitec's mosquitoes began testing in the Cayman Islands, Panama, and

Brazil. But there were concerns about whether mosquitoes bred to survive only in the presence

of antibiotics would spread antibiotic resistant bacteria. Others were worried about the consequences

of some offspring surviving and passing on their modified genes. There's a chance the

offspring could survive if they hatched close to places like sewage treatment plants and

citrus orchards where antibiotics can accumulate. In the last few years, Oxitec has developed

a new male mosquito that circumvents the issue of antibiotics. The updated breed, known by

the designation OX5034, mates with wild females as before. But instead of the offspring all

dying off, only the females die young. The male descendants that inherit the mutation

can reach adulthood, mate, and continue the femicide for generations.

Oxitec claims the total number of modified males will decrease from one generation to

the next, eventually disappearing from the population altogether after 10 generations.

In case you were wondering, the lifespan of an adult Aedes aegypti mosquito is between

two weeks to over a month. So, why are they targeting the female mosquitoes

in particular? Well, it's because male mosquitoes don't bite humans; instead, they can subsist

off nectar. Only females draw blood because their eggs need it to mature, meaning that

females are the ones who can spread disease. That's why Oxitec's plan to release 750

million mosquitoes into the Florida keys isn't as counterproductive as it sounds. They'll

all be male, so the company isn't letting swarms of bloodsuckers loose on all of us.

Still, scientists have voiced concerns. Independent analysis of Oxitec's early trials in Brazil

with their antibiotic-dependent strain, showed that some offspring survived and mated again,

passing on genes to the local mosquitoes. The genes that were passed on weren't the

transgenes that would kill offspring though, just markers that came from the Cuban and

Mexican mosquitoes Oxitec bred to create their homme fatales. Oxitec thinks concerns are

overstated, saying they found about 3% of offspring in lab trials were viable.

The company also claims there's no evidence that cross breeding strains would make the

mosquitoes more harmful to humans or resistant to insecticides. But some scientists are worried

making the gene pool more varied with DNA from other world regions would create hardier

bugs. Others are also concerned that killing off

large numbers of Aedes aegypti could affect the local ecosystem and the animals that feed

on mosquitoes. But Aedes aegypti represent 1% of the Florida Keys mosquito population,

and are likely an invasive species that came to the Americas by ship.

This latest release is also not something that has been decided on a whim; the EPA has

spent years studying the impacts that Oxitec's mosquitoes have on human and environmental

health, and seven Florida state agencies have given the latest trial unanimous approval.

The antibiotic-resistant mosquito variety was also assessed by the FDA and in 2016,

they found it would have no significant negative impact. This second generation genetically

modified mosquito has also already been tested in Brazil, where it temporarily reduced the

Aedes aegypti population by as much as 96%. Though the idea of intentionally releasing

millions of lab-grown mosquitoes may sound like the plot of a B-grade horror movie to

some, lots of research and care has been put into their development. And remember: their

release into the wild is another phase in their testing. If the releases prove ineffective

or harmful, plans for more widespread use can be nixed. Come 2021 — or 2022 — we'll

see if they can help fight the spread of disease and reduce the need to spray pesticides over

the Florida Keys.

While Florida has gotten all the attention, Oxitec has also gotten approval to release

their little buzzers in Texas. While some are growing mosquitoes in a lab, others are

trying to grow a tasty steak. Check out my video on the progress of lab-grown meat here!

So do you think Oxitec and the EPA have done enough research,

or do you think that this tech isn't ready yet? Let us know in the comments, subscribe for

more science news, and I'll see you next time on Seeker.