Humans are getting more fungal diseases, so it is important for health officials to know where these diseases come from. A new study looked for fungi in the lung tissue of small animals and found fungi that cause diseases in humans.
This indicates that these rodents may act as reservoirs, vectors for spreading the fungus, and incubators for new fungus-based diseases.
As the number of fungal infections in the human population rises, it is crucial for health authorities to know their origins. A new study, which was published in the journal Frontiers in Fungal Biology, found that small mammals may be a source of these fungal infections.
The University of New Mexico’s Paris Salazar-Hamm, the study’s lead author, explains, “Our analysis, which specifically focused on lung pathogens that cause disease in humans, detected a wide range of fungi in the lung tissues of small mammals.
They found that many of the rodents they examined in the Southwestern US “were harboring the type of fungi that can cause lung infections in humans, such as the fungus that leads to Valley Fever, a disease that typically causes flu-like symptoms and can be life threatening.”
Jump from animal to human
There has been a rise in reports of novel human diseases over the past four decades. Fungi have also changed and evolved through host jumps, just like the Covid-19 virus. In some situations, this can make them more virulent, which might affect people.
“We wanted to understand if the fungal spores of respiratory pathogens reside in soils because they feed on dead and decaying plant matter, or if they are instead living within small animals and their spores are released into the soil after the rodents die,” adds Salazar-Hamm.
Researchers looked at the DNA of fungi in lung tissue from museum specimens of rodents. They did this by using a technique called “next-generation sequencing,” which lets scientists quickly look at a wide range of fungal species.
“We detected the fungus Coccidioides, the cause of Valley Fever, in the lung tissues of animals from Kern County, California, and Cochise and Maricopa Counties in Arizona, areas that have high rates of this disease,” says Salazar-Hamm.
Additionally, they found Coccidioides sequences in animals from Catron, Sierra, and Socorro Counties in New Mexico, marking the first time this virus has been found in the area’s environment.
“This is the first big study using next-generation sequencing to assess the fungi in the lungs of small mammals,” she adds.
“Our results support the hypothesis that rodents could be a breeding ground for respiratory fungal pathogens.”
“Current forecasts of the distribution of Coccidioides, based on climate and soil conditions,” according to Salazar-Hamm, “predict that Valley fever will expand substantially northward and eastward over the next century as a result of climate change impacting environmental conditions.
“Our results will inform these modeling efforts by adding valuable information about animals as reservoirs for pathogens.”
Future research aims to investigate the host animals’ health and how this may affect the virulence or spread of the diseases.
“We were not able to assess the health of the mammalian hosts from which the lung tissues were acquired. Despite the presence of pathogens, it was impossible to say conclusively that there was disease,” said Salazar-Hamm.
“It would be interesting to further explore the impact of the fungi on the mammals. That effort would require more detailed information about the general health of the animal in question.”
Image Credit: Getty