Prevalence of Giardia intestinalis and other zoonotic intestinal parasites in private household dogs of the Hachinohe area in Aomori prefecture, Japan in 1997, 2002 and 2007

An epidemiological study on canine intestinal parasites was undertaken to evaluate changes in the prevalence among private household dogs from the Hachinohe region of Aomori prefecture, Japan, in 1997, 2002 and 2007, using the formalin-ethyl acetate sedimentation technique. The risk of zoonotic transmission from household dogs to humans was also discussed. All intestinal parasites detected in the present study (Giardia intestinalis, Isospora spp., Toxocara canis, Ancylostoma caninum, Trichuris vulpis and Strongyloides stercoralis) showed no changes in prevalence over the past 10 years based on analysis considering canine epidemiological profiles. In particular, prevalence of Giardia intestinalis in dogs under 1 year old, derived from pet shops/breeding kennels and kept indoors was unchanged, remaining at a high level of >15.0% at each time point. Toxocara canis also showed no changes in the group of dogs under 1 year old, bred by private owners and kept outdoors, and the prevalence was >10.0% every year. The present results indicate that the prevalence of Giardia intestinalis and other intestinal parasites in private household dogs has not always decreased, and the potential for direct parasitic zoonotic transmission from dogs to humans may be relatively high level, than from the environment (indoors and outdoors). We recommend careful surveillance of intestinal parasites and aggressive use of anthelminthic in private household dogs under considering the epidemiological factors.