A fungal disease is threatening snakes in the Midwest and eastern United States, and researchers are using PCR as part of a test to diagnose the infection quickly and accurately and track its progression. While this research focuses on a single type of infection, similar studies could help researchers around the world address animal disease that could threaten ecosystems, and even pass on to humans.

Eastern massasauga rattlesnake

Credit: Matthew Allender

Matthew Allender, a professor in comparative biosciences at the University of Illinois, has created the test for Ophidiomyces ophiodiicola to be faster, more accurate and less invasive test.

Photo by L. Brian Stauffer

Photo by L. Brian Stauffer

“We need people to know that they don’t have to anesthetize an animal to collect a biopsy sample or, worse yet, euthanize snakes in order to test for the infection,” says Allender, an expert in snake fungal disease. “Now we can identify the infections earlier, we can intervene earlier and we can potentially increase our success of treatment or therapy.”

The new test uses quantitative polymerase chain reaction (qPCR), which amplifies fungal DNA to identify the species present and measure the extent of infection.

“Our qPCR is more than 1,000 times more sensitive than conventional PCR,” says Allender. “We can know how many [fungal spores] are in a swab, and then we can start to treat the snake and we can watch to see if that number is going down.”

This fungal infection, first spotted in snakes in the mid-2000s, now threatens the last remaining eastern massasauga rattlesnake population in Illinois and has been found to infect timber rattlesnakes, mud snakes, rat snakes, garter snakes, milk snakes, water snakes and racers in several states. There are only 100 to 150 massasaugas left in Illinois, according to Allender, and about 15% of those are infected with the disease.

Ophidiomyces consumes keratin, a key ingredient in snake scales. It can cause scabs, nodules, abnormal moulting, ulcers and other disfiguring changes to snake skin. Mortality can be up to 100% once snakes show outward signs of infection.

The qPCR test will help researchers to understand the biological and health factors that lead to infection, as well as supporting the development of new therapies to treat infections in snakes, and disinfectants to prevent its spread.

“This work is truly collaborative across disciplines, allowing the team to make advances in studying this disease that haven’t been accomplished anywhere else,” Allender said.