The health department in the US state of Massachusetts announced the first case of a person infected with Eastern equine encephalomyelitis (EEE) this year in mid-August. At the end of August, the neighboring state of New Hampshire reported the first death of an infected person in 2024.

EEE is transmitted by a specific kind of mosquito and, according to the US Centers for Control and Disease Prevention, the disease is fatal in 30% of cases. Many survivors are left with neurological problems. There is currently no available vaccine or medication.

Several US states have therefore now taken measures to reduce the risk of mosquito bites, introducing temporary and localized lockdowns and the use of pesticides to curb the mosquito population.

Claim: On social media, many users are making a connection between the current cases of EEE in the US and the release of genetically modified mosquitoes bred by the company Oxitec, which is sponsored by the Bill & Melinda Gates Foundation, among others (here, here, here and here). 

One X user comments: "What's going on with Bill Gates and his mosquito farm? There's an uptick in EEE virus in humans, especially in New England area! Well what I mean is BG has a fkn mosquito farm in Medallin Colombia so yeah did they get out?"

On Facebook, someone writes: "EEE is spread by mosquitoes. Bill Gates is invested in GMO mosquitoes. What're the odds against a sudden pandemic of EEE in the US prior to the upcoming presidential election?" 

So does billionaire Bill Gates have anything to do with EEE?

DW fact check: False

The mosquito is one of the most dangerous insects in the world. The females — only they bite — can transmit various types of pathogens, including viruses and parasites. Every year over 700,000 people worldwide die from mosquito-borne diseases.

To combat this public health problem, the Bill & Melinda Gates Foundation is supporting the company Oxitec, among others, which is experimenting with genetically modified mosquitoes. In 2020, the biotech company officially received permission to release the laboratory-bred mosquitoes although they had to be geographically limited to Florida. The aim is to reduce the pest population.

"Male mosquitoes will be genetically modified so that they are sterile so that when a female mates with a sterile male, there's no viable offspring. Over time that decreases populations of mosquitoes, and this has been used successfully in Brazil," said Amesh Adalja from the Johns Hopkins University Center for Health Security.

Such research methods have been studied for some time and other sterile animals, such as irradiated worms in agriculture, have also been used.

Only female mosquitoes transmit EEE

Oxitec confirmed to DW that no genetically modified mosquitoes have been released in Massachusetts. The last release was in Florida, in November 2023, meaning the genetically modified mosquitoes can hardly be related to the current EEE outbreak in terms of space and time. And since the animals are male and don't bite, they wouldn't be able to transmit EEE themselves anyway. 

The virus also existed long before the use of genetically modified mosquitoes. "We've known about it for 90 years. So this is not a new virus. And it's a mosquito-borne virus. That's endemic to our region and occasionally when the right conditions are met, we'll see periodic outbreaks." explained Dr. Philip M. Armstrong, a scientific director at the Center for Vector Biology and Zoonotic Diseases in Connecticut. 

"It's been a reasonably wet, warm summer, which has created ideal conditions for mosquito breeding," he added. "Particularly the mosquito that transmits triple E virus, which lives in these freshwater swamp habitats in our region."

Bill Gates a frequent target of conspiracy theories

Bill Gates has often been the target of disinformation and conspiracy myths. For example, social media users also suspected that the genetically modified Oxitec mosquitoes were behind the dengue outbreak in Brazil at the beginning of the year and cases of malaria in the US in 2023.

During the COVID-19 pandemic, the Microsoft founder was accused of secretly implanting microchips with the COVID-19 vaccine. And fake news circulated in India that he was on trial for illegally testing polio vaccines on children.

Gates, one of the world's richest people, founded the Bill & Melinda Gates Foundation along with his ex-wife, Melinda Gates. It's the largest private foundation in the world. Since its establishment in 2017, it has invested tens of billions of euros worldwide in thousands of projects and organizations in the health care sector, including vaccination programs and vaccine research.

Gates' very real influence on global health care is one of the things that makes many so suspicious and fuels disinformation. The billionaire is a target for the conspiracy myths around him. A deep skepticism toward society's elites is a typical characteristic of such narratives.

This article was originally written in German.