Snakes Facing Extinction Due to Disease, New Study Reveals

According to a recent study, snakes are at a significant risk of extinction caused by a lethal disease. Rattlesnakes, in particular, are highlighted as being among the most endangered species globally.

The study points out that infectious diseases, often introduced by parasites and fungi, play a crucial role in this crisis, similar to habitat destruction.

To assess the health of snakes, researchers in the U.S. examined seven different pathogens in wild snakes, analyzing disease prevalence over time, location, and among various species.

One notable disease, ophidiomycosis, also referred to as snake mycosis, has emerged as a significant issue. This disease is due to the fungus Ophidiomyces ophidiicolla.

Since its identification two decades ago, this fungus has been detected in numerous snake species.

Dr. Corinna Misin, who led the study, indicated that the fungus and another parasite, Railietiella orientalis, are major sources of infection for wild snakes, especially in the southeastern U.S. They found that snakes experiencing co-infection had a notably higher risk of developing ophidiomycosis.

The findings, published in *Frontiers in Veterinary Science*, were based on the analysis of over 500 snakes from 29 different species collected from wildlife refuges in South Carolina and Florida, alongside samples from other areas in the Southeast.

Most of the snakes were captured alive; they underwent swabbing, blood sampling, and some deceased snakes found on roads were fully examined for tissue analysis.

Dr. Misin noted that for about ten years prior, studies on these snakes focused mainly on one particular disease. They aimed this research at gaining a more holistic understanding of snake health.

Interestingly, nearly 20% of the snakes showed no detectable pathogens. Salmonella enterica was the most frequent pathogen found, appearing in 63% of the snakes, with Hepatozoon spp., a tick-borne parasite, affecting just over half of the samples.

A potentially serious concern is the discovery of antibiotic-resistant Mycoplasma spp., found in 18% of the snakes. This bacterium can trigger upper respiratory issues and was previously unrecorded in wild snakes in the U.S.

Shockingly, about 44% of the snakes examined were found to harbor multiple pathogens.

The researchers identified combinations of two, three, or four pathogens in 29%, 11%, and 3% of the snakes, respectively.

Professor Misin elaborated that when snakes contract infectious diseases, their immune systems can falter, thereby increasing vulnerability to other pathogens that may not have previously shown symptoms.

The study also suggested that certain snake species are more likely to be infected based on their health status. For instance, pygmy rattlesnakes were identified as particularly susceptible to fungal diseases.

Twelve of the 34 tested rattlesnakes showed positive signs for the fungus, with many exhibiting illness symptoms. In contrast, only one of 55 eastern ribbon snakes and three of 36 ringneck snakes were infected.

Moreover, rattlesnakes were found to be the primary hosts of Railietiella orientalis, with 14 out of 34 infected individuals. Other species exhibited lower infection rates or none at all.

According to Professor Misin, certain species, like rattlesnakes, might be more prone to disease due to their decreasing populations and historical threats from humans. Additionally, their typical diet increases exposure to the parasite.

She mentioned that various factors also determine the likelihood of a snake carrying a pathogen. For instance, snakes from Georgia had a higher occurrence of the fungus, while Railietiella was only found in snakes from Florida.

Skin lesions, too, were noted to contribute to the spread of the fungus; over 30% of snakes with such lesions were diagnosed with infections, compared to just 2% of those without.

Misin remarked that detecting Railietiella in living snakes can be challenging, as fecal analysis may not always yield consistent results due to their eating habits, suggesting the real infection rates might be underestimated.

Despite the limitations, she emphasized the significance of this research for snake conservation and managing invasive species. Invasive species, like Burmese pythons, are known to be capable hosts for the same parasites.

In conclusion, Misin stated, “Our findings help outline which pathogens native snakes may possess and which they might be free from. This information is vital for preventing the transfer of pathogens from captive snakes during transportation, protecting wildlife health.”