Project Results

About This Project

Ophidiomycosis (snake fungal disease) is a threat to snake health. Caused by the fungus Ophidiomyces ophiodiicola, it affects over 30 wild snake species and can cause skin abnormalities, internal lesions, and even death. Differences in disease signs may be due to snakes' response to infection. We plan to measure innate immune function in Lake Erie watersnakes with a range of ophidiomycosis lesions to determine if disease severity is associated with immune function.

Ask the Scientists

What is the context of this research?

Ophidiomycosis was first identified in 2003 and affects more than 30 species of wild snakes in at least 34 states in the US as well as in Europe. It has been associated with at-risk species, including Timber rattlesnakes, massasauga rattlesnakes, and eastern indigo snakes. The disease was diagnosed in Lake Erie watersnakes in 2009 and up to 55% of these snakes are affected. Differences in innate immunity may explain why some snakes are more severely affected than others. As the primary defense against infection in reptiles, innate immunity can be assessed through the lysis of sheep red blood cells by serum complement proteins and the activity of chitotriosidase, an enzyme that breaks down chitin and is associated with antifungal defenses in alligators.

What is the significance of this project?

Ophidiomycosis can affect all snake species, so it is critical to know why snakes are variably susceptible in order to design conservation programs that protect snake health. Snakes benefit humans by controlling populations of rodents and ticks that carry zoonotic diseases and benefit global health by maintaining biodiversity. Snake populations worldwide are declining due to climate change, habitat destruction, and infectious disease, among other factors, and little is known about the reptile immune system, particularly the response to fungal infection. This project will directly benefit Lake Erie watersnakes, which have a high prevalence of ophidiomycosis and only recently recovered from critically low population numbers.

What are the goals of the project?

In summer 2019, we will capture 40 Lake Erie watersnakes with a range of skin lesions (10 unaffected, 10 mild, 10 moderate, 10 severe) and (1) collect blood for innate immune function testing, (2) swab the snakes’ skin for quantification of the fungal load, and (3) record lesion number, type, size, and location on the body. Serum will be tested for chitotriosidase activity and lysis of sheep red blood cells. DNA will be extracted from swabs and qPCR will be used to quantify the amount of fungus present on each snake's skin. Finally, the lesion characteristics will be used to assign a disease severity score. All of these observations will be analyzed in fall 2019 to determine if there is an association between innate immune function and severity of disease.