509 snakes tested in US survey, many found carrying disease-causing pathogens

A study involving a major survey of the health status of wild reptiles in the southeastern region of the United States found widespread diseases caused by fungi, parasites, and bacteria in hundreds of snakes.

According to Discover Wildlife and a detailed study published in Frontiers in Veterinary Science, the survey tested 509 snakes from 29 species in Florida, Georgia, and South Carolina. According to scientists working on the project, the data collected provided a unique insight into the potential health threats facing local snake populations amid ongoing pressure from habitat loss and environmental changes.

Teams of scientists from the University of Georgia and other institutions worked for four years to collect tissue samples from snakes living in various wetland and forest habitats. Seven potential pathogens affecting the health status of snakes were assessed in the study.

The survey revealed that exposure to multiple pathogens was widespread among the snakes studied.

Nearly half of the snakes carried multiple pathogens
As noted by the study, 44 percent of the snakes were found to be positive for more than one pathogen.

Salmonella enterica was detected to be the most prevalent infectious organism in the sample group, present in 62.6 percent of the snakes. Meanwhile, 53.4 percent of the snakes were infested by the parasite Hepatozoon, whereas 17.5 percent of them hosted Mycoplasma bacteria.

Ophidiomyces ophidiicola, the fungus causing snake fungal disease, was detected in 16.1 percent of the analyzed snakes. The pathogens may be present in a healthy animal without leading to symptoms. But the experts believe that the simultaneous presence of multiple pathogens increases the risk of infection and its severity.

"A snake can carry a pathogen and still appear completely healthy," lead author Corinna Hazelrig said in comments released alongside the study. "What matters is understanding what pushes infection into something deadly."

Snake fungal disease remains a concern

Among the conditions examined in the survey, snake fungal disease emerged as one of the major concerns. The infection is caused by the fungus Ophidiomyces ophidiicola and has been known to affect snakes in North America for the last few years.

Earlier studies had highlighted that the infection was associated with skin ulcers, scabs, swelling, difficulty shedding skin, and even mortality in snakes.

In this study, it was seen that the snakes with a greater number of infections were the ones with snake fungal disease. In addition to this, there was also an association between infection and poor body condition in snakes. It is still unclear how these diseases are associated with each other.

Pygmy rattlesnakes are among the hardest hit


One particular species caught researchers’ attention.The pygmy rattlesnake (Sistrurus miliarius), which is a smaller venomous snake commonly distributed across various southeastern regions of the United States, showed particularly high infection levels. It was stated that the species seemed quite susceptible to the impacts of the SFD among other snakes included in the study.

The researchers concluded that further observation was necessary with regard to this particular species without predicting any drastic impacts on its population.

Invasive parasite detected in Florida
Another parasite investigated in the study was the parasitic lungworm Raillietiella orientalis.

This worm was discovered only in snakes sampled from Florida, but not found in snakes sampled from Georgia and South Carolina. The previous research indicates that the worm has been imported into Florida together with invasive Burmese pythons. Researchers found an association between infection and poorer body condition.

As the scientists say, Burmese pythons can tolerate the presence of this parasite, but local snakes may not be able to do the same.

Why snake health matters

Despite being overlooked by many compared to mammals and birds, experts say that snakes are essential elements within ecosystems, helping to maintain balance and keep them healthy.

Snakes play important roles in food webs. They help control populations of rodents and other small animals while also serving as prey for larger predators. As such, disease epidemics that would threaten the life of the animals could ripple through local food webs.

According to Nicole Nemeth, the senior author of the study and the director of research and diagnostics at the University of Georgia's Southeastern Cooperative Wildlife Disease Study, wildlife populations often suffer from numerous environmental stressors simultaneously, thereby providing pathogens with favorable conditions to emerge.

The scientists believe that their work creates a valuable point of reference for subsequent studies on wildlife disease control and conservation. In particular, the results obtained from the findings could help researchers identify areas of infection occurrence and species affected by emerging diseases.