Human-mediated determinants of trypanocide use in dogs in Southeastern Nigeria: a cross-sectional survey with implications for resistance and One Health

Trypanocide resistance is an escalating threat to African animal trypanosomosis control, yet how dogs are actually treated for trypanosomosis, by who, with what drugs, and under what oversight, remains poorly characterized despite the documented presence of resistant trypanosome populations in this neglected host compartment. In a cross-sectional survey interpreted within a One Health framework, grounded in data from Enugu North Senatorial Zone, Southeastern Nigeria, we integrate previously published molecular and epidemiological data on canine trypanosomes with original cross-sectional survey data from 120 dog-owning households and 250 dogs. Associations are descriptive and inferential; no new resistance assays or transmission studies were undertaken. Survey data revealed that 87.5% of treated dogs received treatment without prior parasitological confirmation, 83% received doses estimated without weight-based calculation, and 76.7% of households obtained trypanocides from unregulated sources. Only 38.3% had geographic access to a licensed veterinarian, and 60% reported no community access to diagnostic testing. Inter-household dog movement was documented in 44.2% of households and 57.5% reported livestock co-habitation. These findings are consistent with sustained selective pressure for resistance, interpreted alongside published evidence of diminazene-resistant and multidrug-resistant Trypanosoma isolates from the same zone. Dogs emerge as plausible reservoirs and amplifiers of drug-resistant trypanosomes within a One Health framework, posing risks to livestock productivity and public health. The molecular identification of Trypanosoma brucei gambiense in study-area dogs warrants structured surveillance investigation. Direct transmission pathways were not evaluated. Addressing these drivers requires robust veterinary drug regulation, expanded veterinary service access, community education, and integration of companion animals into national trypanosomosis surveillance frameworks.