Canine gastrointestinal parasites as a potential source of zoonotic infections in Nigeria: A nationwide survey

•First nationwide survey using morphological and molecular approaches reveals widespread infections of dogs in Nigeria with potentially zoonotic parasites.•Risk of infection is associated with free roaming dogs and those that do not receive regular deworming treatment.•The environment is prone to contamination with potentially zoonotic parasites from feces of stray dogs.•Mass deworming of dogs along with mass administration of anthelmintic to children should be considered in line with the One Health paradigm. Dog feces may contain zoonotic parasites that contaminate the environment and serve as a potential source of infection to animals and humans. In this study, microscopic and molecular analyses were used to estimate the prevalence and intensity of gastrointestinal (GI) parasites and assess the risk factors for infection in 948 dogs in three climatically distinct zones of Nigeria. Zoonotic helminths including Strongyloides stercoralis, Ancylostoma braziliense, A. caninum and Toxocara canis were detected either as single or multiple infections in 377 (39.8 %) of dogs examined. At multiple logistic regression analyses, association was found between GI parasite infection and deworming practices and dog management. Regarding A. braziliense, A. caninum and T. canis infections, intensity of egg shedding was statistically associated with the age of the dogs and not with their sex or breed. The majority of GI parasite-positive dogs did not receive regular deworming treatment (59 %) and roamed freely (56 %) thereby constituting public health risk. This is the first nationwide survey and analyses of risk factors of GI parasites of dogs using molecular methods as confirmation of their identity. The zoonotic potential of these parasites is exacerbated by the lack of both operational national policies to control the population of free-roaming dogs and to promote responsible dog ownership, and veterinary public health programs for dogs.