Prevalence of Endoparasites in Urban Stray Dogs from Brazil Diagnosed with Leishmania, with Potential for Human Zoonoses

Background In tropical environments, abandoned animals can be an important source for human zoonotic infections, such as human visceral leishmaniasis and other vector-borne diseases. Here, we report the frequency of protozoan and helminth intestinal parasites in stray dogs, which might have an implication for human health in urban Brazilian settings. Material and Methods We performed necropsies on 93 animals, euthanized due to canine visceral leishmaniasis control program, and examined their intestines looking for the presence of helminths; we determined the parasite load, and the elimination of eggs and cysts of protozoan parasites in fecal samples. Further, we performed serology tests for the detection of specific antibodies against Toxoplasma gondii . Results Overall, a high prevalence of intestinal parasites with potential for human zoonoses resulted and only 8.6% of examined intestines remained negative. The most prevalent helminths were Ancylostoma caninum and Dipylidium caninum . For nematodes, high worm burdens were detected for A. caninum and Trichuris vulpis . Additionally, we analyzed worm burdens and quantitative stool examinations, but found no significant association between positive serology for Leishmania infection and intestinal parasite burden. Interestingly, serology for T. gondii infection revealed a prevalence of 33.3% and a positive result was significantly associated with a higher A. caninum adult worm recovery ( p = 0.0087). Conclusion Our results showed stray dogs living in urban areas are heavily parasitized, which presents a potential risk for humans. Beyond the control of canine visceral leishmaniasis, we propose an improvement of the control program to reduce the risk for other parasitic diseases in dogs and humans.