BALTIMORE, Sept. 28 (UPI) -- There may be an answer for malaria being more prevalent in some places than in others: fungus.
Researchers at Johns Hopkins University identified a fungus that appears to dampen the Anopheles mosquito's immune system and increase the chance for their infection with the Plasmodium parasite that causes malaria in humans, according to a study published in the journal Scientific Reports.
Mosquitoes pick up the Plasmodium parasite when they bite humans carrying it, and spread it by then biting a healthy human, infecting them.
In 2015, 89 percent of malaria cases and 91 percent of malaria deaths were in the sub-Saharan region of Africa but why cases are so concentrated in one area of the world has confounded doctors and researchers.
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The researchers say they are already aware of microbes that prevent Anopheles mosquitoes from being infected by the parasite but that this is the first time something has been found to increase their likelihood of acquiring it.
"We have questions we hope this finding will help us to answer, including why do we have increased transmission of malaria in some areas and not others when the presence of mosquitoes is the same?" Dr. George Dimopoulos, a professor of molecular microbiology and immunology and deputy director of the Malaria Research Institute at Johns Hopkins, said in a press release. "This gives us another piece of the complicated malaria puzzle."
The researchers identified the Penicillium chrysogenum fungus, which is in the same family of fungus used to produce penicillin, in the gut of mosquitoes. They thought it might be added to the list of fungi identified by researchers that blocks mosquitoes from acquiring the parasite, finding instead that it does the opposite.
While the newly-identified fungus compromises the mosquitoes' immune system, so the Plasmodium parasite can more easily infect the insects, the researchers say it may still help with work on a vaccine against malaria.
Development of a malaria vaccine has been difficult for researchers, with experimental versions being designed and redesigned for decades, though some promise has been seen in recent years -- for example, the PfSPZ vaccine tested at the University of Maryland earlier this year in a phase 1 clinical trial.
"This very common, naturally occurring fungus may have a significant impact on malaria transmission: It doesn't kill the mosquitoes, it doesn't make them sick, it just makes them more likely to become infected and thereby to spread the disease," Dimopoulos said. "While this fungus is unlikely to be helpful as part of a malaria control strategy, our finding significantly advances our knowledge of the different factors that influence the transmission of malaria."
