Bill Gates-funded company did not cause malaria cases in Florida

A post on Twitter retweeted over 20,000 times says: “It must be a coincidence that from 2003-2023 there wasn’t one case of Malaria spread by mosquitos…and along comes a company funded by Bill Gates…to solve a problem that didn’t exist…and suddenly in the exact places where he releases mosquitos…there’s an outbreak of Malaria?”

The claim has also been shared many times on Facebook.

The post seems to be alluding to a company called Oxitec, which has received funding from Bill Gates’s charitable foundation and has research facilities based near Oxford. 

The company has released a genetically modified mosquito species that mates with local pests in order to create offspring that won’t survive until adulthood, to reduce the pest population. The species released isn’t the one that transmits malaria, and in the US, the company’s mosquitoes have so far only been released in Florida. 

The locally-acquired malaria cases have been identified in Florida and Texas.

A spokesperson for Oxitec told Full Fact there was “absolutely no truth to these claims” and that they were “scientifically impossible”.

Some locally acquired cases of malaria have recently been identified in the US

The tweet appears to be referring to recent cases of locally acquired malaria in Texas and Florida. The US Centers for Disease Control and Prevention (CDC) said on 26 June that five cases of locally acquired malaria cases had been identified in the last two months—four in Florida and one in Texas.

The CDC also said there had been no locally acquired mosquito-borne malaria in the US since 2003, when eight cases were identified in Florida, so the post is right in that respect.

The vast majority of malaria cases in the US are travel-related, occurring when someone has been bitten by malaria-carrying mosquitoes abroad before arriving in the US. The CDC says there are around 2,000 such cases a year.

Were the new cases in areas where mosquitoes have been released?

The tweet claims a company “funded by Bill Gates” released mosquitoes “to solve a problem that didn’t exist”, and that these are the “exact places” where “there’s an outbreak of malaria”.

This appears to be a reference to the biotechnology company Oxitec, which has received funding from the Bill & Melinda Gates Foundation. A spokesperson for Oxitec told Full Fact that no US-based work by Oxitec is funded by the Bill & Melinda Gates Foundation.

A spokesperson for the foundation told us it doesn’t fund any work involving mosquito release in the United States.

Oxitec has worked with Florida Keys Mosquito Control to release a genetically modified version of a mosquito species called Aedes aegypti, which is an invasive species and can transmit diseases like dengue, zika and yellow fever. The genetic modification means that when the released mosquitoes (which are all male) mate with local females, their offspring don’t survive until adulthood.

Vitally, these Aedes aegypti mosquitoes do not transmit malaria, which is caused by a parasite and spreads between humans via various female Anopheles mosquito species, not Aedes aegypti. 

And only female mosquitoes of all species bite and feed on the blood of mammals and by doing so spread disease—males lack the appropriate body parts to effectively pierce skin. Oxitec only released male insects.

So the locally acquired cases of malaria are likely to have spread via Anopheles mosquitoes. The CDC says in its release about the locally acquired malaria cases that “Anopheles mosquito vectors, found throughout many regions of the country, are capable of transmitting malaria if they feed on a malaria-infected person”.

According to Oxitec, releasing their genetically modified males eventually causes a 90% reduction in the population of the pest mosquitoes in urban pilots, compared to untreated areas.

Although the Environmental Protection Agency did grant Oxitec an Experimental Use Permit in 2020 to release their mosquitoes in Harris County, Texas, in 2021, there is no evidence any mosquitoes were released there. A spokesperson for Oxitec confirmed that none had been released there and there are currently no plans to do so.

So malaria hasn’t been seen in the “exact places” the mosquitoes were released.

As for the claim that the company was solving “a problem that didn’t really exist”, while it’s true that locally-acquired malaria is not a common problem in the US, locally transmitted dengue has been observed in the country, particularly in Florida, and is spread by the Aedes aegypti mosquito.

False claims like this about public health risk contribute to the spread of health misinformation especially if people falsely believe influential figures are causing outbreaks of disease. Misinformation connecting unrelated research and disease outbreaks risks causing unnecessary alarm.

We’ve fact checked several claims regarding Bill Gates, especially on the subject of public health due to his charitable work in the area, including false claims that he wanted to put vaccines in the food supply, that he launched artificial breastmilk and that his daughter wasn’t vaccinated.

A spokesperson for the foundation he formed with his ex-wife Melinda French Gates told Full Fact: “Malaria eradication has been a top priority of our foundation for more than two decades, and we remain committed to devoting resources and expertise toward the goal of ending the disease for good.”

Image courtesy of the CDC