genetically modified mosquitoes

Genetically Modified Mosquitoes Stunt Malaria Parasite Growth, Prevent Transmission

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Scientists led by researchers from the Transmission:Zero team at Imperial College London have engineered mosquitoes that slow the growth of malaria-causing parasites in their guts, and prevent transmission of the disease to humans. The mosquitoes carry a genetic modification that causes them to produce compounds in the gut that stunt the growth of the malaria parasites, meaning that the parasites are unlikely to reach the mosquitoes’ salivary glands and be passed on to a human in a bite before the insects die.

The research team showed that the strategy can dramatically reduce the possibility of malaria spreading, in a lab setting. If proven safe and effective in real-world settings it could offer a powerful new tool to help eliminate malaria. Collaborators from the Institute for Disease Modeling at the Bill and Melinda Gates Foundation also developed a model that, for the first time, can assess the impact of such modifications if used in a variety of African settings. They found that the modification developed by the Transmission:Zero team could be a powerful tool for bringing down cases of malaria even where transmission is high.

The innovation is designed so it can be coupled with existing “gene drive” technology to promote the spread of the modification and drastically cut malaria transmission. The researchers aim to test whether their approach can block the transmission of parasites that have infected humans, as well as those that have been lab-reared. The safety of the new modification will be tested thoroughly before combining it with a gene drive for real-world tests.

If all goes well, field trials are anticipated within 2–3 years. George Christophides, PhD, a professor in the department of life sciences at Imperial, said, “History has taught us that there is no silver bullet when it comes to malaria control, thus we will have to use all the weapons we have at our disposal and generate even more. Gene drive is one such very powerful weapon that in combination with drugs, vaccines, and mosquito control can help stop the spread of malaria and save human lives.”

Christophides is co-lead author of the team’s published paper in Science Advances, which is titled, “Gene drive mosquitoes can aid malaria elimination by retarding Plasmodium sporogonic development.”

Malaria remains one of the world’s most devastating diseases, putting at risk about half of the world’s population. In 2021 alone, the disease infected 241 million and killed 627,000 people, mostly children aged below five years, in sub-Saharan Africa.

The authors wrote, “Despite the availability of the first World Health Organization–approved malaria vaccine the necessity to develop alternative intervention strategies remains pressing, particularly if malaria elimination is to remain the goal.” Co-first author Tibebu Habtewold, PhD, at the department of life sciences at Imperial, further explained, “Since 2015, the progress in tackling malaria has stalled. Mosquitoes and the parasites they carry are becoming resistant to available interventions such as insecticides and treatments, and funding has plateaued. We need to develop innovative new tools.”

Malaria is transmitted between people after a female mosquito bites someone infected with the malaria parasite. The parasite then develops into its next stage in the mosquito’s gut and travels to its salivary glands, ready to infect the next person the mosquito bites.

However, only around 10% of mosquitoes live long enough for the parasite to develop far enough to be infectious. The team aimed to lengthen the odds even further, by extending the time it takes for the parasite to develop in the gut.

The Transmission:Zero team genetically modified Anopheles gambiae, the primary malaria-carrying species of mosquito in sub-Saharan Africa. On taking a blood meal, mosquitoes with the modification produce two antimicrobial peptides (AMPs) in the gut, which impair the malaria parasite’s development. The two peptides are magainin 2, which was first found within skin secretions of the African claw frog Xenopus laevis, and melittin, a primary toxin component of the European honey bee Apis mellifera.

Inhibiting the parasite’s development causes a few days’ delay before the next parasite stage could reach the mosquito salivary glands, by which time most mosquitoes in nature are expected to die. The peptides work by interfering with the energy metabolism of the parasite, which also has some effect on the mosquito, causing them to have a shorter lifespan and further decreasing their ability to pass on the parasite. “As the modification additionally reduces female mosquito life span, the possibility of infectious sporozoites to be transmitted to a new host is reduced markedly,” the team stated in the published report.

Professor George Christophides, PhD, holds a cage of mosquitoes. [Imperial College London]

Co-first author of the study Astrid Hoermann, PhD, from the department of life sciences at Imperial, said: “For many years, we have been trying to no avail to make mosquitoes that cannot be infected by the parasite or ones that can clear all the parasites with their immune system. Delaying a parasite’s development inside the mosquito is a conceptual shift that has opened many more opportunities to block malaria transmission from mosquitoes to humans.”

If the genetic modification is to help prevent malaria spread in the real world, it will need to be spread from lab-bred mosquitoes to wild populations. Normal interbreeding would achieve this to a certain degree, but because the modification has a “fitness cost” in the form of reduced lifespan, it would likely be quickly eliminated as a result of natural selection.

Gene drive is an additional genetic trick that could be added to the mosquitoes and cause preferential inheritance of the antiparasite genetic modification, making it spread more widely among any natural populations. And as the researchers further noted, “Modeling suggests that propagation of this modification via gene drive promises to break the malaria transmission cycle across a range of epidemiological scenarios in sub-Saharan Africa even if the effector itself is eventually replaced by resistant alleles because of the fitness cost that it imposes.”

For the reported study, the researchers demonstrated that the small genetic modifications to the malaria mosquitoes successfully impeded transmission of two different malaria parasite Plasmodium species, the deadliest human parasite, P. falciparum, and the rodent parasite P. berghei. “It achieves this by hampering parasite sporogonic development that occurs in the oocyst, markedly delaying the emergence of infectious sporozoites, and we attribute this effect to the known propensity of these AMPs for interfering with mitochondrial function,” they wrote.

The authors acknowledged that their strategy would require careful planning to minimize any risks before field trials can be considered. The Transmission:Zero team is creating two separate, but compatible strains of modified mosquitoes—one with the antiparasite modification and one with the gene drive.

They can then test the antiparasite modification on its own first, only adding in the gene drive once it has been shown to be effective. Co-lead author Nikolai Windbichler, PhD, from the department of life sciences at Imperial, said, “We are now aiming to test whether this modification can block malaria transmission not just using parasites we have reared in the lab but also from parasites that have infected humans. If this proves to be true, then we will be ready to take this to field trials within the next two to three years.”

With partners in Tanzania, the team has set up a facility to generate and handle genetically modified mosquitoes and conduct some initial tests. These include collecting parasites from locally infected schoolchildren, to ensure that the modification works against the parasites circulating in relevant communities.

They are also fully risk-assessing any potential releases of modified mosquitoes, taking into account any potential hazards and making sure they have acceptance from the local community. But they are hopeful that their intervention can ultimately help to eradicate malaria.

The investigators concluded in their paper, “This modification is already designed for gene drive and requires no further adjustment before deployment, while, at the same time, it is inert on its own and thus can be safely tested in an endemic setting under standard containment protocols. It thus enables the next step for testing antimalarial effectors, i.e., to evaluate their transmission blocking modifications against parasites directly sampled from patients in malaria-endemic countries.”

Bill Gates-Funded Company Releases Genetically Modified Mosquitoes in US

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Genetically modified mosquitoes have been released for the first time in the United States as part of an experiment to combat insect-borne diseases such as Dengue fever, yellow fever, and the Zika virus.

UK-based biotechnology firm Oxitec, which is funded by the Bill and Melinda Gates Foundation, said it released the mosquitoes in six locations in Monroe County’s Florida Keys: two on Cudjoe Key, one on Ramrod Key, and three on Vaca Key.

It’s part of an effort to help tackle a disease-transmitting invasive mosquito population—the Aedes aegypti mosquito species—that’s responsible for “virtually all mosquito-borne diseases transmitted to humans,” according to the company.

These mosquitoes make up about 4 percent of the mosquito population in the Keys, and transmit dengue, Zika, yellow fever, and other human diseases, as well as heartworm and other potentially deadly diseases to pets and other animals.

The experiment is in collaboration with the Florida Keys Mosquito Control District (FKMCD), and was approved by the U.S. Environmental Protection Agency (EPA), the Florida Department of Agriculture and Consumer Services (FDACS), the U.S. Centers for Disease Control and Prevention, and an independent advisory board.

Over the next 12 weeks, fewer than 12,000 mosquitoes are expected to emerge each week, for approximately 12 weeks. Untreated comparison sites will be monitored with mosquito traps on Key Colony Beach, Little Torch Key, and Summerland Key.

If successful, some 20 million additional genetically modified mosquitoes will be released later in the year.

“We really started looking at this about a decade ago, because we were in the middle of a dengue fever outbreak here in the Florida Keys,” FKMCD Executive Director Andrea Leal said during a video news conference. “So we’re just very excited to move forward with this partnership, working both with Oxitec and members of the community.”

The insects released by the biotechnology firm are all male, so they don’t bite. They’re expected to mate with the local biting female mosquitoes, and in doing so, they will pass on a lethal gene that will ensure their female offspring die before reaching maturity.

According to Quartz, areas including Malaysia, Brazil, the Cayman Islands, and Panama, where similar experiments have been carried out, have seen mosquito populations drop by as much as 90 percent.

The project has faced backlash from residents, who say their consent was not sought for the experiment.

FDA Approves Genetically Modified Mosquitoes to Combat Zika in Florida 

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Amid news of a Zika outbreak in the Miami area, the U.S. Food and Drug Administration’s Center for Veterinary Medicine (FDA-CVM) has cleared the experimental release of genetically modified (GMO) mosquitoes in the Florida Keys to help combat the virus.

The agency also concluded that the proposed field trial “will not have significant impacts on the environment”—on the food chain, for instance—after considering thousands of public comments.

Oxitec is calling for a release of thousands of its GMO mosquitoes in the Florida Keys to combat the Zika virus.Oxitec Twitter

The purpose of the investigational trial is to determine the efficacy of Oxitec’s GMO mosquitoes for the control of the local population of Aedes aegypti in Key Haven, a small community about a mile east of Key West. County residents will vote this November on whether or not to allow the field tests to proceed.

The mosquitoes in question were created by Oxitec, a UK-based biotech firm that specializes in insect control. Pending approval, Oxitec will release its “self-limiting OX513A Aedes aegypti,” a male GMO mosquito that does not bite or spread disease, to mate with wild female Aedes aegypti, the primary vector that carries the Zika virus. The lab insects carry a gene that’s fatal to offspring, meaning the local population will dwindle over time at the release site.

“We’ve been developing this approach for many years, and from these results we are convinced that our solution is both highly effective and has sound environmental credentials,” Oxitec’s CEO Hadyn Parry said. “We’re delighted with the announcement today [on Aug. 5] that the FDA, after their extensive review of our dossier and thousands of public comments for a trial in the Florida Keys, have published their final view that this will not have a significant impact on the environment. We are now looking forward to working with the community in the Florida Keys moving forward.”

Parry estimated to the Guardian that 20 to 100 mosquitoes per person will be released on the island.

Prior efficacy trials in Brazil, Panama and the Cayman Islands reduced the Aedes aegyptipopulation by more than 90 percent—”an exceptional level of control compared to conventional methods, such as insecticides,” Oxitec said.

As The Verge noted, Oxitec’s rate is much more successful compared to efforts by the Florida Keys Mosquito Control District. The program, which utilizes conventional control methods such as pesticides sprayed from trucks and planes and mosquito traps, reduced mosquito populations by 30 to 60 percent.

Oxitec’s trial in Florida will run for between six and 22 months.

“Oxitec is responsible for ensuring all other local, state, and federal requirements are met before conducting the proposed field trial, and, together with its local partner, the Florida Keys Mosquito Control District, to determine whether and when to begin the proposed field trial in Key Haven, Florida,” the FDA said.

The FDA also said that its decision to approve Oxitec’s Florida field trials does not mean the GMO mosquitoes are approved for commercial use.

The Zika virus has spread with alarming speed throughout South and Central America. The island of Puerto Rico has more than 8,000 confirmed cases of Zika with officials estimating that cases will skyrocket. The state of Florida now has 422 cases—more than any other state in the nation, asPOLITICO pointed out.

The mosquito-borne Zika virus has been linked to microcephaly, a rare neurological condition which leads to abnormal brain development in babies. The World Health Organization has declared the situation an international public health emergency.

Scientists have suspected that climate change is exacerbating the problem of longer mosquito-active seasons. As the Natural Resources Defense Council wrote:

A new analysis by Climate Central highlights that the number of days hot and humid enough for mosquitoes to be active and biting has increased in many big U.S. cities—and climate change will further increase those numbers, in most locations. In their analysis, the ten cities with the biggest increase in the length of the mosquito season over the last 30 years were: Baltimore, Maryland; Durham, North Carolina; Minneapolis; Myrtle Beach, South Carolina; Raleigh, North Carolina; Portland, Maine; St. Louis; Pittsburgh; Worcester, Massachusetts ; and Albany, New York. These cities cover a huge swath of the eastern U.S. Nationwide, 76 percent of major cities have seen their mosquito season get longer over that time.

This adds a whole other dimension to the public health challenges of Zika: climate change could make more areas of the U.S. more susceptible to this and other mosquito-borne pathogens in the future. Increased heat, disrupted precipitation patterns and higher humidity can allow mosquitoes to thrive in new places, as the Natural Resources Defense Council (NRDC) reported in our Fever Pitch report about dengue fever, another infectious viral disease that can be carried by the same two Aedes mosquito species. Warmer temperatures enable mosquitoes to develop more quickly and to incubate viruses that can infect people faster. Thus, climate change can hasten the spread of many infectious diseases, including Zika.

Besides Zika, the Aedes aegypti transmits other viruses such as dengue, yellow fever and chikungunya.

Critics are voicing concerns over the Florida GMO mosquito project. A release from Common Dreams highlighted Oxitec’s connection to its parent company, Intrexon, which produces non-browning Arctic apples and fast-growing AquaBounty salmon—two highly controversial GMO food products.

Some public health advocates have also pointed out that the long-term environmental effects of GMO mosquitoes are unknown.

“Releasing GMO mosquitoes into the environment without long term environmental impact studies is irresponsible and frightening,” Zen Honeycutt, director of the anti-GMO group Moms Across America, said in reaction to the FDA’s decision. “What about the creatures who eat the mosquitoes and all the life forms up the food chain? The impact could be irreversible … Allowing uncontrollable genetically altered life forms into the wild is not justified.”

A Change.org petition, signed by nearly 170,000 people, has called on government officials to reject Oxitec’s trial involving “mutant mosquitoes,” the petition states.

FDA Considering the Release of Genetically Modified Mosquitoes

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The U.S. Food and Drug Administration (FDA) says genetically modified mosquitoes are no danger to the environment or humans. The federal agency of the United States Department of Health and Human Services is considering a field trial of releasing genetically modified mosquitoes in the Florida Keys.

On Friday, the FDA released documents for public comment pertaining to their review of information regarding genetically modified mosquitoes provided from Oxitec, Ltd. — a British biotech firm.

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Genetically Modified Mosquitoes

Aedes aegypti mosquitoes are a non-native species in the United States. Besides being a nuisance, this mosquito strain can spread serious diseases — like chikungunya and dengue fever.

In order to produce mosquito offspring that will not survive outside a laboratory, Oxitec modifies Aedes aegypti mosquitoes with synthetic DNA. The biotech company has already conducted similar tests in the Cayman Islands, Brazil, and Panama. The Telegraph reports that releasing genetically modified mosquitoes in Brazil “has seen populations of infectious insects fall by 90 per cent.”

Currently the Florida Keys — including Key West — are not experiencing outbreaks of chikungunya and dengue fever. However, the Florida Keys Mosquito Control District (FKMCD) has been working with Oxitec in an attempt to reduce the Aedes aegypti pest. They are searching for ways to keep mosquito populations down to an acceptable level. The FDA, the World Health Organization (WHO), and FKMCD believe that the Oxitec technology is an innovative tool in the fight against mosquitoes.

According to a report by The Washington Post regarding the FDA’s decision, “The agency’s Center for Veterinary Medicine released a preliminary finding that no significant impact would result from the trial of a method that aims to reduce populations of the mosquito that spreads dengue, chikungunya and the Zika virus among humans.”

As part of the World Health Organization’s efforts to join the fight against Aedes aegypti mosquitoes, the organization has been considering research into a gene drive. If successful, a gene drive could ultimately overtake populations of mosquitoes with genetically modified mosquitoes that would be incapable of spreading the Zika virus.

In their Strategic Response Framework & Joint Operation Plan the WHO noted, “There are a range of vector control measures for the mosquitoes known to spread the Zika virus. Recent developments, such as progress in mosquitoes modified to carry Release of Insects with Dominant Lethality (RIDL) traits or the use of gene drives, [offer] opportunities for novel approaches.”

Opposing GM Mosquitoes

Oxitec faces some strong opposition to the company’s genetically modified mosquitoes. The Washington Post cites, “Oxitec’s goal is to sell its mosquitoes and services in the way that other companies sell insecticides.”

The Florida Keys Environmental Coalition, a residents’ group against the spread of genetically modified mosquitoes, wants the district to try infecting mosquitoes with a bacteria that curbs their ability to transmit disease, instead of spreading genetically modified misquotes over the area. The group argues that Oxitec’s proposal is mostly marketing propaganda and won’t be subject to enough federal oversight.

On Monday, the coalition’s executive director, Barry Wray, sent an email to the Associated Press. Wray questioned the ongoing costs of Oxitec’s method.  Wray wrote, “Oxitec has exploited the fear surrounding Zika very effectively. When you start looking at the quantity of mosquitoes they need to continuously provide, in order to keep problems under control, the numbers are astounding. So is the money required!”

Oxitec’s trials of genetically modified mosquitoes have been widely criticized. Critics say additional proof is required with regards to stray female GM mosquitoes. Do these genetically modified mosquitoes spread genetic material through bites? In addition, could there be other environmental risks — such as another disease-carrying mosquito species infestation?

The Plan

A brief description of the Florida Keys Project is explained on Oxitec’s website. Oxitec and FKMCD are working on informing the Florida Keys community about the mosquito releases and to answer any questions the public may have.

The Food and Drug Administration Center for Veterinary Medicine (FDA-CVM) is working with other agencies for federal regulation of this project. The other agencies include the Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC).

If the FDA agrees that releases can proceed following their current review, Oxitec male mosquitoes would be released up to three times a week. The results of the project will be made available to the public.

Zika Outbreak Epicenter In Same Area Genetically-Modified Mosquitoes Released In 2015

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The World Health Organization announced it will convene an Emergency Committee under International Health Regulations on Monday, February 1, concerning the Zika virus ‘explosive’ spread throughout the Americas. The virus reportedly has the potential to reach pandemic proportions — possibly around the globe. But understandingwhy this outbreak happened is vital to curbing it. As the WHO statement said:

“A causal relationship between Zika virus infection and birth malformations and neurological syndromes … is strongly suspected. [These links] have rapidly changed the risk profile of Zika, from a mild threat to one of alarming proportions.

 

“WHO is deeply concerned about this rapidly evolving situation for 4 main reasons: the possible association of infection with birth malformations and neurological syndromes; the potential for further international spread given the wide geographical distribution of the mosquito vector; the lack of population immunity in newly affected areas; and the absence of vaccines, specific treatments, and rapid diagnostic tests […]

 

“The level of concern is high, as is the level of uncertainty.”

Zika seemingly exploded out of nowhere. Though it was first discovered in 1947, cases only sporadically occurred throughout Africa and southern Asia. In 2007, the first case was reported in the Pacific. In 2013, a smattering of small outbreaks and individual cases were officially documented in Africa and the western Pacific. They also began showing up in the Americas. In May 2015, Brazil reported its first case of Zika virus — and the situation changed dramatically.

Brazil is now considered the epicenter of the Zika outbreak, which coincides with at least 4,000 reports of babies born with microcephaly just since October.

zika-microcephaly

When examining a rapidly expanding potential pandemic, it’s necessary to leave no stone unturned so possible solutions, as well as future prevention, will be as effective as possible. In that vein, there was another significant development in 2015.

Oxitec first unveiled its large-scale, genetically-modified mosquito farm in Brazil in July 2012,with the goal of reducing “the incidence of dengue fever,” as The Disease Daily reported. Dengue fever is spread by the same Aedes mosquitoes which spread the Zika virus — and though they “cannot fly more than 400 meters,” WHO stated, “it may inadvertently be transported by humans from one place to another.” By July 2015, shortly after the GM mosquitoes were first released into the wild in Juazeiro, Brazil, Oxitec proudly announced they had “successfully controlled the Aedes aegypti mosquito that spreads dengue fever, chikungunya and zika virus, by reducing the target population by more than 90%.”

Though that might sound like an astounding success — and, arguably, it was — there is an alarming possibility to consider.

Nature, as one Redditor keenly pointed out, finds a way — and the effort to control dengue, zika, and other viruses, appears to have backfired dramatically.

zika

Juazeiro, Brazil — the location where genetically-modified mosquitoes were first released into the wild.

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Map showing the concentration of suspected Zika-related cases of microcephaly in Brazil.

The particular strain of Oxitec GM mosquitoes, OX513A, are genetically altered so the vast majority of their offspring will die before they mature — though Dr. Ricarda Steinbrecher published concerns in areport in September 2010 that a known survival rate of 3-4 percent warranted further study before the release of the GM insects. Her concerns, which were echoed by several other scientists both at the time and since, appear to have been ignored — though they should not have been.

Those genetically-modified mosquitoes work to control wild, potentially disease-carrying populations in a very specific manner. Only the male modified Aedes mosquitoes are supposed to be released into the wild — as they will mate with their unaltered female counterparts. Once offspring are produced, the modified, scientific facet is supposed to ‘kick in’ and kill that larvae before it reaches breeding age — if tetracycline is not present during its development. But there is a problem.

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Aedes aegypti mosquito. Image credit:Muhammad Mahdi Karim

According to an unclassified document from the Trade and Agriculture Directorate Committee for Agriculture dated February 2015, Brazil is the third largest in “global antimicrobial consumption in food animal production” — meaning, Brazil is third in the world for its use of tetracycline in its food animals. As a study by the American Society of Agronomy, et. al., explained,“It is estimated that approximately 75% of antibiotics are not absorbed by animals and are excreted in waste.” One of the antibiotics (or antimicrobials) specifically named in that report for its environmental persistence is tetracycline.

In fact, as a confidential internal Oxitec document divulged in 2012, that survival rate could be as high as 15% — even with low levels of tetracycline present. “Even small amounts of tetracycline can repress” the engineered lethality. Indeed, that 15% survival rate was described by Oxitec:

“After a lot of testing and comparing experimental design, it was found that [researchers] had used a cat food to feed the [OX513A] larvae and this cat food contained chicken. It is known that tetracycline is routinely used to prevent infections in chickens, especially in the cheap, mass produced, chicken used for animal food. The chicken is heat-treated before being used, but this does not remove all the tetracycline. This meant that a small amount of tetracycline was being added from the food to the larvae and repressing the [designed] lethal system.”

 

Even absent this tetracycline, as Steinbrecher explained, a “sub-population” of genetically-modified Aedes mosquitoes could theoretically develop and thrive, in theory, “capable of surviving and flourishing despite any further” releases of ‘pure’ GM mosquitoes which still have that gene intact. She added, “the effectiveness of the system also depends on the [genetically-designed] late onset of the lethality. If the time of onset is altered due to environmental conditions … then a 3-4% [survival rate] represents a much bigger problem…”

 

As the WHO stated in its press release, “conditions associated with this year’s El Nino weather pattern are expected to increase mosquito populations greatly in many areas.”

Incidentally, President Obama called for a massive research effort to develop a vaccine for the Zika virus, as one does not currently exist. Brazil has now called in 200,000 soldiers to somehow help combat the virus’ spread. Aedes mosquitoes have reportedly been spotted in the U.K. But perhaps the most ironic — or not — proposition was proffered on January 19, by the MIT Technology Review:

“An outbreak in the Western Hemisphere could give countries including the United States new reasons to try wiping out mosquitoes with genetic engineering.

 

“Yesterday, the Brazilian city of Piracicaba said it would expand the use of genetically modified mosquitoes …

 

“The GM mosquitoes were created by Oxitec, a British company recently purchased by Intrexon, a synthetic biology company based in Maryland. The company said it has released bugs in parts of Brazil and the Cayman Islands to battle dengue fever.”

Biotech company to release millions of genetically modified mosquitoes in Florida.

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mosquitos 2
When chemistry falls short, biotechnology is ready to pick up the slack in the southern US. The UK-based biotech firm Oxitec is working on a plan with the FDA to combat mosquito-transmitted disease with genetically modified organisms rather than chemical pesticides. If the plan is approved, millions of genetically modified mosquitoes could be released in the Florida Keys with the aim of reducing the population of mosquitoes capable of transmitting two tropical diseases, dengue and chikungunya.

Researchers say the warming climate has pushed tropical diseases like dengue and chikungunya further north. These are both viral infections carried by mosquito species like Aedes aegypti, which transmits the virus to humans when biting. Both viruses cause extreme muscle and joint pain, fever, nausea, and plenty of other unpleasant symptoms. Dengue can occasionally progress to life threatening hemorrhagic fever as well. Chikungunya is also known to cause chronic disease that results in joint and muscle pain for years after the initial infection.

Basically, these are diseases you do not want to get, but they’re starting to pop up in Florida. There are no approved vaccines that can prevent infection with either virus, so mosquito control is seen as the only viable option. Local governments have taken to spraying six different pesticides in an attempt to keep the mosquito populations under control, but A. aegypti has already evolved resistance to four of the six agents. It’s much harder for mosquito populations to adapt if you’re targeting them with DNA, though.

Oxitec’s plan involves the production of mosquitoes with modified genetic code containing DNA from the herpes simplex virus, E. coli, coral, and cabbage plants. This is accomplished by injecting eggs with modified DNA as seen below. Millions of these organisms would be bred, then the females would be removed from the population before release. Females are the ones that bite and drink blood, so only non-biting male mosquitoes should be released in Florida, assuming the FDA approves.

injection-of-mosquitoes-eggs-picture-good3

These GMO insects will go about their business doing regular mosquito things until they mate with wild female mosquitoes. The modified DNA in the experimental insects will cause all the offspring from this union to die, thus reducing the population of mosquitoes by crowding out wild-type males that can produce viable offspring. This also means the GMO mosquitoes are self-limiting as they cannot reproduce.

Oxitec has conducted initial tests in Brazil and the Cayman Islands, both of which were successful enough that the countries are planning larger deployments of GMO mosquitoes. If approved by the FDA, Oxitec could release the bugs this spring in southern Florida. However, there is local opposition to the plan, based at least partially on a lack of understanding. A Change.org petition (with nearly 150,000 signatures) makes a number of misrepresentations and omissions in its portrayal of the plan.

That’s not to say there are no concerns. For example, it’s possible some female mosquitoes could be accidentally released and bite humans. Oxitec says even if that happens, there’s no evidence that would result in the transfer of modified DNA, or that such a thing would harm anyone. It’s up to the FDA now to decide if the project goes forward, but Oxitec does have a lot of data to show their method is effective and safe from laboratory testing as well as the tests in Brazil and the Cayman Islands.