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Researchers say they have identified a fungus that compromises mosquitoes’ immune systems, making them more susceptible to infection with malaria parasites.
Malaria researchers have, in the past, identified microbes that prevent the Anopheles mosquito from being infected by malaria parasites, but this is the first time they have found a microorganism that appears to make the mosquito more likely to become infected with—and then spread—malaria.
The finding was published in Scientific Reports.
“This very common, naturally occurring fungus may have a significant impact on malaria transmission,” said study author George Dimopoulos, PhD, of the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland.
“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. 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.”
For this study, Dr Dimopoulos and his colleagues isolated the Penicillium chrysogenum fungus from the gut of field-caught Anopheles mosquitoes. The team found this fungus made the mosquitoes more susceptible to being infected by Plasmodium parasites through a secreted heat-stable factor.
The researchers said the mechanism behind this increased susceptibility involves upregulation of the mosquitoes’ ornithine decarboxylase gene, which sequesters arginine for polyamine biosynthesis.
They noted that arginine plays an important role in the mosquitoes’ anti-Plasmodium defense as a substrate of nitric oxide production, so the availability of arginine has a direct impact on susceptibility to infection with Plasmodium parasites.
Dr Dimopoulos said Penicillium chrysogenum had not previously been studied in terms of mosquito biology, and he and his team had hoped the fungus would act like several other bacteria that researchers have identified, which prevent mosquitoes from becoming infected with malaria parasites.
Even though Penicillium chrysogenum actually appears to worsen infections, the team believes the fungus can still help researchers in their fight against malaria.
“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 Dimopoulos said. “This gives us another piece of the complicated malaria puzzle.”
Because environmental microorganisms can vary greatly from region to region, Dr Dimopoulos and his colleagues believe their finding may help explain variations in the prevalence of malaria in different geographic areas. 
Photo by James Gathany
Researchers say they have identified a fungus that compromises mosquitoes’ immune systems, making them more susceptible to infection with malaria parasites.
Malaria researchers have, in the past, identified microbes that prevent the Anopheles mosquito from being infected by malaria parasites, but this is the first time they have found a microorganism that appears to make the mosquito more likely to become infected with—and then spread—malaria.
The finding was published in Scientific Reports.
“This very common, naturally occurring fungus may have a significant impact on malaria transmission,” said study author George Dimopoulos, PhD, of the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland.
“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. 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.”
For this study, Dr Dimopoulos and his colleagues isolated the Penicillium chrysogenum fungus from the gut of field-caught Anopheles mosquitoes. The team found this fungus made the mosquitoes more susceptible to being infected by Plasmodium parasites through a secreted heat-stable factor.
The researchers said the mechanism behind this increased susceptibility involves upregulation of the mosquitoes’ ornithine decarboxylase gene, which sequesters arginine for polyamine biosynthesis.
They noted that arginine plays an important role in the mosquitoes’ anti-Plasmodium defense as a substrate of nitric oxide production, so the availability of arginine has a direct impact on susceptibility to infection with Plasmodium parasites.
Dr Dimopoulos said Penicillium chrysogenum had not previously been studied in terms of mosquito biology, and he and his team had hoped the fungus would act like several other bacteria that researchers have identified, which prevent mosquitoes from becoming infected with malaria parasites.
Even though Penicillium chrysogenum actually appears to worsen infections, the team believes the fungus can still help researchers in their fight against malaria.
“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 Dimopoulos said. “This gives us another piece of the complicated malaria puzzle.”
Because environmental microorganisms can vary greatly from region to region, Dr Dimopoulos and his colleagues believe their finding may help explain variations in the prevalence of malaria in different geographic areas.
Photo by James Gathany
Researchers say they have identified a fungus that compromises mosquitoes’ immune systems, making them more susceptible to infection with malaria parasites.
Malaria researchers have, in the past, identified microbes that prevent the Anopheles mosquito from being infected by malaria parasites, but this is the first time they have found a microorganism that appears to make the mosquito more likely to become infected with—and then spread—malaria.
The finding was published in Scientific Reports.
“This very common, naturally occurring fungus may have a significant impact on malaria transmission,” said study author George Dimopoulos, PhD, of the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland.
“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. 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.”
For this study, Dr Dimopoulos and his colleagues isolated the Penicillium chrysogenum fungus from the gut of field-caught Anopheles mosquitoes. The team found this fungus made the mosquitoes more susceptible to being infected by Plasmodium parasites through a secreted heat-stable factor.
The researchers said the mechanism behind this increased susceptibility involves upregulation of the mosquitoes’ ornithine decarboxylase gene, which sequesters arginine for polyamine biosynthesis.
They noted that arginine plays an important role in the mosquitoes’ anti-Plasmodium defense as a substrate of nitric oxide production, so the availability of arginine has a direct impact on susceptibility to infection with Plasmodium parasites.
Dr Dimopoulos said Penicillium chrysogenum had not previously been studied in terms of mosquito biology, and he and his team had hoped the fungus would act like several other bacteria that researchers have identified, which prevent mosquitoes from becoming infected with malaria parasites.
Even though Penicillium chrysogenum actually appears to worsen infections, the team believes the fungus can still help researchers in their fight against malaria.
“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 Dimopoulos said. “This gives us another piece of the complicated malaria puzzle.”
Because environmental microorganisms can vary greatly from region to region, Dr Dimopoulos and his colleagues believe their finding may help explain variations in the prevalence of malaria in different geographic areas.