Zoonotic gastrointestinal parasites of shelter dogs in Israel

Dogs are potentially infected with a diverse spectrum of endoparasites, some which may affect their health or be of zoonotic concern. In Israel, no information exists on the prevalence and spatial distribution of endoparasitic infection among dogs. An investigation of the prevalence of endoparasite infection in Israel shelter dogs was performed by fecal flotation and molecular methods, with particular interest in parasites of zoonotic concern. Polymerase-chain reaction (PCR) was performed targeting the small subunit ribosomal RNA (rrnS) of Taenia spp.,-cox1 mitochondrial DNA of Strongyloides spp., and 18S rRNA of Cryptosporidium spp. The study included fecal samples of 393 dogs from six municipal shelters in different areas of Israel. Overall, 92 of 393 (23.4 %) dogs were infected with at least one endoparasite. According to fecal microscopy, 7.4 % were infected with Cystoisospora spp.; 7.1 % with Giardia intestinalis; 1.0 % with Toxocara canis; 3.1 % with Toxascaris leonina; 2.5 % with Sarcocystis spp.; 2.3 % shed taeniid eggs; 0.3 % Spirocerca lupi eggs; 0.3 % hookworm spp. eggs and 0.3 % shed Hammondia heydorni oocysts. PCR for Taenia spp. detected 1.8 % dogs with Taenia hydatigena, and 0.51 % dogs with Taenia spp. eggs.

Several epidemiologically significant points were identified; Ta. leonina was more prevalent in dogs from the north of Israel, while Sarcocystis spp. and Taenia eggs were more prevalent in the south. In addition, infection with Ta. leonina was found to be significantly increased in summer compared to other seasons. This is the first large scale study of endoparasites in dogs from Israel, with results showing presence of potentially zoonotic parasites, T. canis, Giardia spp. and hookworms. These results should serve to increase awareness of veterinarians, human infectious disease specialists, and dog shelter personnel of relevant parasites to plan better prevention, diagnosis and treatment schemes in dog shelters and to look for suggestive signs of endoparasite-related disease in a One Health framework.