1Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA; 2Veterinary Diagnostic and Investigational Laboratory, College of Veterinary Medicine, University of Georgia, Tifton, GA, USA; 3Animal Health Diagnostic Center, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA; Present address (Sheldon): Illinois Zoological and Aquatic Animal Residency Program, College of Veterinary Medicine, University of Illinois, Urbana, IL, USA
An outbreak of canine distemper virus (CDV) caused the death of five adult Linnaeus’s two-toed sloths (Choloepus didactylus) living in separate enclosures in a building at a private zoo in eastern Tennessee during a 2-wk period. Clinical signs included oral and nasal discharge and ulcerations, diarrhea, lethargy, and anorexia. Diagnosis was confirmed via necropsy, histopathology, immunohistochemistry, virus isolation, and PCR. Viral sequencing identified the strain to be consistent with a new CDV lineage currently affecting domestic dogs and wildlife in Tennessee.3,4 Canine distemper has not been previously reported in any species in the super order Xenarthra.1,2 Seven sloths (three surviving the outbreak, and four animals added after the outbreak) were sedated, examined, and vaccinated with a recombinant CDV vaccine (Recombitek C3, Merial, 1 ml s.c.) on day 0, and again on day 21. Blood was collected and CDV antibody titers were measured prior to initial vaccination in all seven sloths and on day 49 in four sloths (two sloths died of non-CDV disease before day 49 and an adequate sample could not be obtained in one sloth). Serology revealed negative titers (<1:32) on day 0 in six of seven sloths, and titers increased by day 49 in three of four sloths with seroconversion in two sloths and a 32-fold increase in one sloth. No adverse effects of vaccination were observed. Based on this outbreak and serologic findings post vaccination without adverse effects, the authors recommend recombinant CDV vaccination in sloths exposed to known carriers of CDV.
The authors would like to thank the animal care staff of the Bright’s Zoo, Drs. Linden Craig and Allison Watson of the Anatomic Pathology service at the University of Tennessee College of Veterinary Medicine, and the technical staff of the Cornell virology lab.
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