Terra R. Kelly, DVM; Jonathan M. Sleeman, VetMB, MRCVS
The medical records of 48 red foxes (Vulpes vulpes), 35 gray foxes (Urocyon cineroargenteus), and 10 foxes of unspecified species examined at the Wildlife Center of Virginia (WCV) from 1993 to 2001 were reviewed to determine causes of morbidity and mortality. The most common diagnosis in red foxes was orphaned (33%), followed by trauma (27%), undetermined diagnosis (23%), and sarcoptic mange (17%). Trauma (46%) was the most frequent cause of morbidity and mortality in gray foxes followed by orphaned (23%), undetermined (20%), toxoplasmosis (6%), presumptive canine distemper (3%), and rabies (3%). One gray fox had concurrent toxoplasmosis and presumptive canine distemper. Similar diseases were detected compared to previous studies;2,3 however, trauma and orphaned animals were over-represented, and infectious diseases were under-represented, supporting the hypothesis that submissions to wildlife centers are biased towards human-associated problems. The lack of diagnostic information on some cases limited the usefulness of this study. For example, it is possible that canine distemper is a more significant cause of morbidity and mortality in gray foxes presented to the WCV. All seven of the undetermined gray fox cases presented with seizures as the primary clinical sign. However, definitive diagnoses were not made due to the lack of postmortem examinations performed. This clinical presentation is very suspicious for canine distemper in this species.1 Wildlife centers can play a role in disease monitoring; therefore, more emphasis should be placed on performing ancillary diagnostic tests and postmortem examinations of wildlife presented to these centers.
We thank the pathologists at Augusta Medical Center, Fishersville, VA for performing the histopathology and S. Snead for technical assistance.
1. Davidson WR, Nettles VF. Field manual of wildlife diseases in the southeastern United States. Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, 1997:174–190.
2. Davidson WR, Nettles VF, Hayes LE, Howerth EW, Couvillion CE. Diseases diagnosed in gray foxes (Urocyon cinereoargenteus) from the southeastern United States. J Wildl Dis. 1992;28:28–33.
3. Little SE, Davidson WR, Howerth EW, Rakich PM, Nettles VF. Diseases diagnosed in red foxes from the southeastern United States. J Wildl Dis. 1998;34:620–624.