Snake fungal disease is a growing health concern for snake populations worldwide. This emerging wildlife disease threatens individual snakes and the stability of their populations. Its increasing prevalence highlights its importance for conservation and ecosystem health.
Understanding Snake Fungal Disease
Snake fungal disease (SFD), also known as ophidiomycosis, is a skin infection affecting snakes. It is caused by the fungus Ophidiomyces ophiodiicola, which attacks the scales of snakes. SFD was first definitively identified in a population of Timber Rattlesnakes in New Hampshire in 2006, though earlier suspected cases date back to 1992. It is considered an emerging threat to snake populations across various regions, including North America and Europe. The fungus itself is an environmental saprobe, and it is likely that it resides in soil.
Symptoms and How it Spreads
Snakes afflicted with SFD exhibit several visible signs, primarily affecting their skin. These symptoms can include localized thickening or crusting of the skin, the appearance of abnormal bumps or nodules beneath the skin, and ulcerated areas. Affected snakes may also experience abnormal molting, where their eyes appear white and cloudy, and severe facial disfiguration. In some instances, the infection can progress internally from the nasal cavity to the eyes, throat, and lungs, potentially causing eye infections and pneumonia.
The disease primarily spreads through contact with contaminated environments, such as soil or burrows where the fungus resides. Infected snakes can shed the fungus into their surroundings, further contaminating the environment. Snakes sharing communal denning or hibernacula sites during winter dormancy are particularly susceptible to transmission due to close contact with contaminated areas and other infected individuals.
Impact on Snake Species and Ecosystems
SFD has severe consequences for individual snakes. Affected snakes may struggle to meet their heightened energy requirements, resulting in emaciation and lethargy. The physical manifestations of the disease, such as disfigurement and lesions, also hinder their ability to move, hunt, and evade predators effectively. Experimental data indicates that infected snakes have an average survival time of approximately 90 days, with a mortality rate of about 40%.
Beyond individual animals, SFD poses a threat to entire snake populations. Numerous snake species have been confirmed to be affected, including milk snakes, black rat snakes, garter snakes, timber rattlesnakes, eastern massasauga, cottonmouth snakes, and black racer snakes. Many snake populations are already experiencing declines, and this fungal disease can accelerate these declines, potentially causing populations to vanish. Population reductions can disrupt food webs, as snakes serve as both predators and prey, impacting ecosystem health.
Addressing the Disease and Broader Concerns
Efforts to address SFD involve a multi-pronged approach, including surveillance programs to monitor its spread and impact on snake populations. Laboratory diagnostics, such as fungal cultures and DNA detection, are employed to confirm the presence of the fungus and accurately diagnose the disease. While treatments for wild snakes, often involving antifungal medications and supportive care, have shown limited success, they are sometimes used for individual cases. Conservation strategies may also include captive breeding programs for vulnerable populations and habitat management to reduce environmental contamination.
A common public concern revolves around whether SFD can affect humans or other pets. Current evidence indicates that the fungus Ophidiomyces ophiodiicola is known to infect only snakes, and there is no direct risk of transmission to humans or non-reptilian pets.