Doctors in the United States have warned people not to swat mosquitoes against their skin.
The fungus is found in mosquitoes
Writing in the New England Journal of Medicine, they said it could increase the risk of serious infection.
It follows the case of a 57-year-old woman who died after developing a fungal infection in her muscles.
Doctors believe she developed the infection after she swatted a mosquito, causing part of the insect to penetrate and infect her skin.
The woman developed a fungal infection called Brachiola algerae.
The infection puzzled doctors, not least because it is thought to be found only in mosquitoes and other insects.
Unlike malaria or West Nile Virus, it is not found in mosquito saliva so doctors were able to rule out a bite as the cause of the infection.
But they concluded that the woman, who died in 2002, probably developed the infection after smearing the insect into a bite.
The case has prompted doctors at Albert Einstein College of Medicine in New York to warn against swatting mosquitoes against the skin.
"I think if a mosquito was in mid-bite, it would be wiser to flick the mosquito off rather than squashing it," said Christina Coyle, one of the authors of the article.
However, Roger Nasci, a mosquito expert at the US Centers for Disease Control in Colorado said there was no scientific basis for switching to flicking.
He added that flicking a mosquito away is only a temporary solution.
"Unfortunately, then the mosquito often goes on to bite another person, or bites you again," he said.
Chris Curtis, professor of medical entomology at the London School of Hygiene and Tropical Medicine, was also sceptical.
"If you flick a mosquito away, they will come back. They are desperate for blood," he told BBC News Online.
"I think it is better to swat the brutes and take the microscopic chance of developing this infection."