Abstract

Published studies of free-ranging snake populations in North America have not included health surveys to date. Some information is available for other regions (e.g., in situ green anaconda health assessments) but is typically restricted to a species-specific investigation rather than including a more comprehensive sampling of other taxa of snakes. This pilot study investigates the feasibility of using dead-on-the-road snakes as one component of assessing the health status of free-ranging snake populations. Formalin-preserved organ samples were obtained from fresh dead-on-the-road (DOR) specimens of snakes collected in Arizona, and H&E-stained sections were observed by light microscopy. Nine DOR snakes collected in 2002 were analyzed. 88.9% (8/9) of the DOR snakes were adult males. One DOR snake was a juvenile crotalid and the gender was not determined. Seven of nine (77.8%) of the DOR snakes were crotalids and 22.2% (2/9) of the DOR snakes were colubrids. Three of nine (33.3%) of the DOR snakes had histologic lesions suggesting an inflammatory or infectious process. Two of nine (22.2%) of the DOR snakes showed signs of inflammatory processes. One of nine (11.1%) had no etiologic agent identified with the inflammatory process. This was a western longnose snake (Rhinocheilus lecontei lecontei) with multifocal, very mild lymphoplasmacytic hepatitis. One of nine (11.1%) showed inflammatory processes and a parasite. This was a western diamondback rattlesnake (Crotalus atrox) with lymphoplasmacytic gastritis and hypertrophic enteritis with coccidian-like intraepithelial protozoa. One of nine (11.1%) showed a parasite (microfilaria) without obvious signs of inflammation. This was a Sonoran gopher snake (Pituophis catenifer affinis) that had massive numbers of microfilaria in the liver vessels and sinusoids. No inclusions similar to inclusion body disease of ophidian paramyxovirus were detected in any of the nine DOR snakes. Additional surveys are recommended to help inform reintroduction and recovery programs.