Florida Keys to release modified mosquitoes to fight insect-borne diseases

ST. PETERSBURG, Fla. (AP) — Sometime next year, genetically modified mosquitoes will be released in the Florida Keys in an effort to combat persistent insect-borne diseases such as Dengue fever and the Zika virus.

The plan approved this week by the Florida Keys Mosquito Control District calls for a pilot project in 2021 involving the striped-legged Aedes aegypti mosquito, which is not native to Florida. But it does transmit several diseases to humans, particularly in the Keys island chain where nearly 50 case of Dengue fever have been reported so far this year.

The plan by the Oxitec biotechnology company is to release millions of male, genetically-altered mosquitoes to mate with the females that bite humans because they need the blood. The male mosquitoes, which don’t bite, would contain a genetic change in a protein that would render any offspring unable to survive — thus reducing the population of the insects that transmit disease, in theory.

Kevin Gorman, an Oxitec scientist, said Thursday in a phone interview from the United Kingdom that the company has done successful such projects in the Cayman Islands and Brazil.

“It’s gone extremely well,” Gorman said. “We have released over a billion of our mosquitoes over the years. There is no potential for risk to the environment or humans.”

Oxitec points to numerous studies by government agencies, ranging from the Environmental Protection Agency to the U.S. Centers for Disease Control and Prevention, that underline the safety of the project. Several Florida government agencies have approved it as well.

Yet, there are people who worry about using genetically-modified organisms, or GMOs, that they believe could alter the planet’s natural balance. At a meeting Tuesday of the Florida Keys mosquito control board, several people questioned the wisdom of the project.

“You have no idea what that will do,” Barry Wray, director of the Florida Keys Environmental Coalition, told the board.

10 PHOTOSMosquito MythsSee GalleryMosquito MythsMyth No.1: Illnesses from mosquitoes aren’t that big of a deal in the United States

Illnesses from mosquito, tick and flea bites have actually tripled in the U.S. over the last 13 years, according to a new report by the Center for Disease Control and Prevention (CDC). There were more than 640,000 cases reported between 2004 and 2016. In addition, nine new germs spread by mosquitoes and ticks were discovered during this time in the United States.

Myth No. 2: Every mosquito could bite you

Only female mosquitoes bite humans because they need nutrients in the blood to produce eggs. Male mosquitoes actually only eat plant matter.

Myth No. 3: Alcohol does not affect your attractiveness to a mosquito

Some small, early studies have shown that consuming a few beers can make you a more appealing snack to a thirsty mosquito. One study showed that consuming just 12 ounces of beer makes a person more likely to be bitten by a mosquito.

There is more research to be done on this topic to fully understand whether or not alcohol, and what type of alcohol, effects your attractiveness to a mosquito, according to Reed.

Myth No. 4: Mosquitoes bite people with sweet blood more often than others

The “taste” of one’s blood has nothing to do with if a mosquito bites your skin or not.

Mosquitoes are attracted to carbon dioxide from breath, heat from our bodies and the lactic acid that humans secrete.

Studies have shown that people with Type O blood are twice as likely to be bitten by mosquitoes than those with Type A blood, possibly due to a difference in lactic acid secretion, according to Reed. Research has not found a reason for this phenomenon, but has noticed this pattern over recent years.

While lactic acid can make a difference, it is not the only factor in what attracts a mosquito to you. Exercising and exerting yourself outdoors increases your attractiveness, according to Reed. As your body temperature increases, the amount of carbon dioxide you’re expelling also increases, making you more attractive to mosquitoes.

Myth No. 5: Citronella candles will completely protect you

Citronella is an ingredient that works to cover up or mask the chemicals that humans secrete that are attractive to mosquitoes.

According to Reed, the candles are only mildly effective. If a mosquito is close enough to your skin it will sense those chemicals despite if the candle is burning or not. These candles will work to keep mosquitoes away from the area, but have a very limited radius.

Citronella candles are most effective when used in enclosed patios and least effective if the wind is blowing strong.

Myth No. 6: All over-the-counter repellents work

While there are many products on the market, the bug sprays proven to be most effective are those that use diethyltoluamide (DEET), a pesticide geared towards protecting you from all sorts of bugs.

When using a DEET-based spray, you should use one that contains 50 percent of DEET or less. Health concerns, including skin and mucus membrane irritation, swarm DEET, but the chemical is non-toxic when used according to directions and provides the best protection against mosquitoes, according to Reed.

Reed recommends using the Environmental Protection Agency (EPA) tool to be sure to find a repellent that will be effective in protecting yourself. Also, you can look for insect repellents with EPA-approved labeling that specifies protection against mosquitoes in general or Aedes mosquitoes in particular.

Myth No. 7: What you wear doesn’t affect your attractiveness to mosquitoes

Researchers have declared that mosquitoes are most attracted to colors that are the most similar to animals that the insects usually prey upon, which are large, dark-colored mammals.

In order to minimize chances on getting bit by a mosquito, Janis recommends wearing loose-fitting, light-colored clothing. Mosquitoes are less attracted to light-colored clothing and the loose-fitting clothing will make it more difficult for biting females to reach your skin through the clothing.

Myth No. 8: Being pregnant makes you a mosquito magnet

Researchers think that because pregnant women give off more carbon dioxide, which is attractive to mosquitoes, that pregnant women may be more likely to get bit.

A study published in 2000 stated that pregnant women are at an increased risk for being bitten by a mosquito, but used a small sample as a test. Ultimately, more research is needed to determine whether or not pregnant women actually have a higher risk of being bitten by a mosquito. Regardless, pregnant women should take extra precautions to avoid mosquitoes in order to evade potential mosquito-borne illnesses.

Myth No. 9: A mosquito dies after it bites you

Unlike some bees, a mosquito does not die after interacting with your skin. Some bees will die after stinging you, but mosquitoes typically bite many times. After a female mosquito bites you she will go off to lay eggs and eventually will be back for more nutrients.

Myth No. 10: Mosquitoes are present all over the world

Mosquitoes have been observed in places as far north as the Arctic tundra and Siberia during the short summers, but have never been found in Antarctica.

The species of mosquitoes that carries Zika, the Aedes species, are not typically found at elevations higher than 6,500 feet (2,000 meters). Many places in South America are so high above sea level that the risk of getting Zika is "minimal," according to the CDC. Locations such as Bogotá, Colombia, and Quito, Ecuador, are popular travel destinations where people can escape these mosquitoes.

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Whether or not the modified mosquitoes can efficiently crash the population of these mosquitoes in Florida remains an open question, some experts say.

“The mosquitoes created in a lab have not gone through a natural selection process, in which only the fittest survive and mate. Once they are released in the natural environment, will they be as fit as the naturally occurring males and able to outcompete them for mates?” said Max Moreno, an expert in mosquito-borne diseases at Indiana University who is not involved in the company or the pilot project.

Another question is whether the mosquitoes may have other unintended effects on the environment. If a spider, frog or bird eats the mosquito, will the modified protein have any effect on the predator?

“An ecosystem is so complicated and involves so many species, it would be almost impossible to test them all in advance in a lab,” said Moreno.

Still, Keys mosquito board members voted 4-1 in favor of the project. One of the supporters, Jill Cranny-Gage, said at the meeting that insecticides and other chemical means have become less effective against the Aedes aegypti mosquito.

“The science is there. This is something Monroe County needs,” Cranny-Gage said. “We’re trying everything in our power, and we’re running out of options.”


Associated Press writer Christina Larson in Washington contributed to this report.

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