As fungal diseases increase in the human population, it is important for public health officials to know where these pathogens come from. A new study led by the University of New Mexico (UNM) has shown that small mammals such as rodents could act as reservoirs, dispersal agents and incubators for fungal pathogens.
“We wanted to understand whether the fungal spores of respiratory pathogens live in soil because they feed on dead and decaying plant matter, or whether they live in small animals instead and their spores are released into the soil after the rodents die,” the said Study lead author Paris Salazar-Hamm, postdoctoral researcher in microbiology at UNM.
“Our analysis, which specifically focused on lung pathogens that cause disease in humans, has identified a variety of fungi in the lung tissue of small mammals. We found that many of the rodents we sampled from areas in the US Southwest harbored the type of fungi that can cause lung infections in humans, such as B. the fungus that leads to valley fever, a disease that typically causes flu-like symptoms and can be life-threatening.”
The scientists used next-generation sequencing – a method that allows rapid detection and assessment of a large number of fungal species – to analyze fungal DNA in rodent lung tissues from museum samples. The study detected the fungus Coccidioides (the causative agent of valley fever) in the lung tissue of small rodents from Kern County, California, and Cochise and Maricopa Counties, Arizona — areas with high rates of this disease — as well as from Catron, Sierra, and Socorro Counties in New Mexico , where this fungus has never been discovered before.
“Current projections of the distribution of Coccidioides, based on climate and soil conditions, predict that Valley Fever will spread significantly north and east over the next century as a result of climate change affecting environmental conditions. Our results will support these modeling efforts by adding valuable information about animals as reservoirs for pathogens,” said Dr. Salazar Hamm.
Future research is needed to assess host animal health and how this might affect disease spread and virulence.
“We could not assess the health of the mammalian hosts from which the lung tissue was obtained. Despite the presence of pathogens, it was impossible to say conclusively that there was a disease. It would be interesting to further explore the effects of fungi on mammals. These efforts would require more detailed information on the general health of the animal in question,” she concluded.
The study is published in the journal Frontiers in Fungal Biology.
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By Andrei Ionescu, Earth.com contributor
