Veterinary Aspects of Establishing a Captive Colony of the Virginia Big-Eared Bat (Corynorhinus townsendii virginianus)
Luis R. Padilla1,2, DVM, DACZM; Katharine L. Hope1,2, DVM; Judilee C. Marrow2, DVM; Warren E. Lynch1; Lisa H. Ware1; Michael T. Maslanka1,2, MS; Tim Walsh2, DVM, DACVP; Tabitha C. Viner2, DVM, DACVP; Linwood Williamson1; Nucharin Songsasen1, PhD; Suzan Murray2, DVM, DACZM; David E. Wildt1,2, PhD
In response to the threat of the advancing “white nose syndrome” epizootic into the range of the Virginia big-eared bat (Corynorhinus townsendii virginianus), the feasibility of establishing a captive, insurance population was explored. Forty adult bats were captured from a cave on 9 November 2009, and placed in an ex situ, indoor, free-flight facility at the Smithsonian Conservation Biology Institute, in Front Royal, VA, USA. Ectoparasites were common, and were eliminated using topical fipronil. Bats were successfully transitioned to feeding on gut-loaded mealworms, initially by hand feeding until adequate self-feeding occurred. The transition occurred slowly over weeks to months, with significant individual animal variation. Supportive care and treatment with fluids was necessary until bats were eating and drinking voluntarily.
Significant morbidity was initially associated with ventral thoracic, cervical and facial dermatitis, likely secondary to excess moisture or adherence of organic material to the fur. Although most cases resolved with treatment, severe cases in debilitated animals presumptively led to septicemia, and death. The onset of a high incidence of carpal abrasions and thumb necrosis correlated with the transition to self-feeding, which in severe cases led to digit amputations and, in some animals, death with presumptive septicemia. Early treatment with systemic and topical agents, including hydroactive gels that prevent excess scar tissue formation, were beneficial to the re-epithelialization of digit abrasions and prevented constrictive band necrosis. Bats could recover and adapt well after thumb amputations. Increased time spent weight bearing or ambulating on carpi and thumbs likely predisposed bats to the development of lesions. Bacteria commonly isolated from sick or dead animals included Serratia marcescens, Staphylococcus sp. and E. coli, suggesting that opportunistic pathogens had invaded open lesions. Animals under chronic systemic antibiotic therapy occasionally developed secondary yeast infections. Cestodiasis, gastric cryptosporidiosis, connective tissue nematodiasis and skin mites were additional findings in some cases. In conclusion, significant challenges were encountered in transitioning the insectivorous Virginia big-eared bat from nature to an ex situ environment.
This work is funded by the U.S. Fish & Wildlife Service (USFWS). The authors thank Barbara Douglas of the West Virginia Field Office of the USFWS, and Craig Stihler of the West Virginia Division of Natural Resources.