Testing the Febrile Response of Snakes Inoculated With Ophidiomyces Ophiodiicola (O.o), the Causative Agent of Snake Fungal Disease

Abstract

Snake Fungal Disease (SFD) is a fungal pathogen of wild snakes populations, predominantly in the Eastern and Midwestern United States. SFD is characterized by heterophilic granulomas that can form around the mouth and eyes with severe cases causing weight loss, impaired vision and eventual death. Researchers, making field observations, have noted early season basking from severely infected snakes. This may suggest that snakes are attempting to raise their body temperature, inducing a febrile response, to combat the mycosis. This study tested the hypothesis that the causative agent of snake fungal disease (Ophidiomyces ophiodiicola) induces a febrile and behavioral response of seeking differential basking temperature to regulate body temperature. Eastern ribbon snakes (Thamnophis sauritus, n=30) were sham or O. o inoculated. Seven days after inoculation, snakes were tested on a thermal gradient that ranged from 40°C to 18°C. The internal body temperature of each snake was measured every 30 minutes for eight hours with a thermal probe inserted into the cloaca of each snake. Additionally, substrate temperatures, where the snake was basking, were measured every 30 minutes, using a laser temperature gun. Snakes inoculated with O. o exhibited significantly higher internal body temperatures and preferred significantly higher temperatures substrate temperatures.