Rodents are ‘breeding grounds’ for life-threatening fungal illnesses in people

ALBUQUERQUE, NM — Seeing a mouse scurrying across the kitchen floor can make even the toughest of us cry out in fear. Now there are even more good reasons to jump out of the way and give your local pest control company a call. Rodents are a breeding ground for life-threatening lung diseases, a new study by University of New Mexico researchers shows.

As fungal diseases in humans are on the rise, scientists have been on a quest to find out why and where these diseases come from. Through their research, they found fungal pathogens in rodent lung tissue that cause disease in humans. This suggests that these little creatures may be transmitting these diseases to us.

“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,” said lead author Paris Salazar-Hamm of the University of New Mexico in a statement. “We have found that many of the rodents we sampled from areas in the southwestern United States harbor the type of fungi that can cause lung infections in humans, such as the fungus that leads to valley fever, a disease typically associated with causes flu-like symptoms and can be life-threatening.”

Like COVID-19, these diseases can jump from body to body, causing them to spread, evolve and diversify rapidly, making the fungi even more harmful to humans. To study the rodents, the scientists used next-generation sequencing, a method that enables a rapid assessment of a wide variety of fungal species.

“We have identified the fungus Coccidioides, the cause of Valley Fever, in the lung tissue of animals from Kern County, California, and Cochise and Maricopa Counties in Arizona, areas with high rates of this disease,” says Salazar-Hamm. “In addition, we have detected sequences of Coccidioides in animals from Catron, Sierra and Socorro counties in New Mexico, marking the first time this pathogen has been detected in the environment of this region.

“This is the first major study using next-generation sequencing to study 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.”

This study is crucial for scientists to figure out where potential diseases could be trapped.

“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,” says Salazar-Hamm . “Our results will support these modeling efforts by adding valuable information about animals as reservoirs of pathogens.”

Next, the scientists plan to study the health of the rodents and see how this may affect the spread or harmfulness of diseases.

“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 disease was present,” says Salazar-Hamm. “It would be interesting to further explore the effects of fungi on mammals. This effort would require more detailed information about the general health of the animal concerned.”

The study is published in the journal Frontiers in Fungal Biology.

South West News Service Alice Clifford contributed to this report.