Zoonotic and non-zoonotic intestinal parasites in shelter dogs at admission and before discharge

Introduction: The prevalence of intestinal parasites, notably zoonotic ascarids and hookworms, is higher in shelter dogs, compared to dogs in homes, making parasite control within shelter facilities a public health priority. Objective: The objective of the study reported here was to measure and compare the frequency of dogs infected with zoonotic or non-zoonotic intestinal parasites at admission and before discharge at a shelter facility. Methods: Ninety-two dogs were tested for diagnosis of intestinal parasites at admission and before discharge. Results: At admission, 50/92 (54%) dogs were diagnosed with intestinal parasites. Most dogs (43/50) were diagnosed with mono-infections with Ancylostoma spp., or co-infections with Ancylostoma spp. and Toxocara sp. or non-zoonotic parasites. Sixty-five dogs had a complete fecal study performed, which included an intake and exit sample analyzed for presence of parasite ova. Among the 65 study dogs, the frequency of dogs with intestinal parasites was lower before discharge (23 or 35%), compared to that at admission (33 or 50%) (P = 0.02). Fifty-one of 65 (78%) dogs were adopted, transferred to an outside rescue facility, or returned to their owners. Of these 51 dogs that left the shelter during the study period, 16/51 (31%) dogs were infected with intestinal parasites, and 8 of the 16 infected dogs were diagnosed with zoonotic parasites. Finally, among 37 dogs that tested negative and 28 that tested positive to zoonotic parasites at admission and re-tested later, four (11%) and six (21%) dogs, respectively, tested positive to zoonotic parasites when tested later. Conclusion: The frequency of shelter dogs infected with intestinal parasites at admission and before discharge was high (≥35%), and most infections were caused by Ancylostoma spp., an intestinal parasite in dogs that can be transmitted to humans, particularly children. We offer health policy options that shelter veterinarians/managers and local policymakers can consider for possible implementation and evaluation.