Endoparasites in dogs diagnosed at the Veterinary Teaching Hospital (VTH)-University of Bologna, combined with clinicopathological results. A long-term retrospective secondary data study

Humans and dogs commonly share the same domestic environment. Europe, and Italy specifically, have a substantial and growing dog population. Potentially zoonotic parasites may be harbored even by dogs receiving regular veterinary care. Thus, transmission of zoonotic or potentially zoonotic parasites to owners and their families should not be underestimated. Frequently, endoparasite infections occur as a subclinical infection and clinicopathological alterations have been documented including anemia, hypoalbuminemia, and eosinophilia. The aim of this large retrospective secondary data study was to analyze coprological endoparasite results and putative risk factors obtained from owned dogs, through a 9-year-period (2011-2019). Possible associations between diagnosed endoparasites and sex, age, seasonality, and year of examination were evaluated. Additionally, parasitological diagnoses were combined to complete blood count parameters and biochemical profiles, when available, to check for any possible hematological alteration from parasitism. A total of 1,972 dogs were evaluated for endoparasites using common fecal diagnostic tests over a 9-year period. The overall proportion of endoparasite-positive animals was 10%. The most common endoparasites detected were Cystoisospora spp. (3%), Toxocara canis (2.8%), Giardia duodenalis (1.6%), and Trichuris vulpis (1.2%). Of these parasites detected, Toxocara poses the greatest zoonotic risk, while Giardia species are considered to have a low potential to be zoonotic. There was no significant diagnostic trend across the years through the study period. Dogs were more frequently diagnosed endoparasite-positive when young and during cold seasons compared to the baselines of mature dogs and warm seasons. The clinicopathological profiles indicated that parasitized dogs had mild hematological alterations. The frequency of detected potentially zoonotic endoparasites in this study highlights that the risk should not be underestimated. Parasitic infection was found to be mostly dependent on age and season. Having this information may help clinicians to develop anthelmintic protocols to reduce the risk of transmission.