The Timber Rattlesnake (Crotalus horridus) is identified as a species of ?Severe Concern' by the Northeast Partners for Amphibian and Reptile Conservation (NEPARC, 2010) and the species is listed as a Species of Greatest Conservation Need in 12 Northeast states. It is believed to be extant in only 10 of those states. A recent study, funded through the Regional Conservation Needs Grants program, evaluated the prevalence of a disease that may be impacting regional Timber Rattlesnake populations.

In 2009, Timber Rattlesnakes were found to have a significant disease identified as fungal dermatitis, which has been shown to cause mortality in Viperdae snakes and may be playing a part in the low population numbers in New England. The study, led by the Roger Williams Park Zoo, sought to provide a baseline health assessment of multiple New England populations of the Timber Rattlesnakes. The data collected provide insights on the prevalence of fungal dermatitis throughout these Timber Rattlesnake populations and can be used for comparison in future years to determine if the prevalence of the disease is increasing.

Ninety-eight snakes from nine populations of Timber Rattlesnakes in New England were captured (and released) for the study, across four seasons between Spring 2013 and Fall 2014.  Once captured, data gathered on the snakes included morphological measurements, gender, an estimate of age, and a visual examination of dermatitis lesions or external abnormalities. In addition, blood was drawn for hematology, serum biochemistry and heavy metal analysis, and two cloacal swabs were obtained for paramyxovirus testing.

The study provides an overall prevalence rate of fungal dermatitis in the nine populations studied of approximately 33 percent. The analyses showed no evidence that the disease is an opportunistic infection in snakes with suppressed immunity, and in fact the sampled snakes appeared to be in overall good health. Data from the study is being analyzed further for a future submission to the Journal of Zoo and Wildlife Medicine. View the final report and more information on the study. (mg)