Prevalence and spatial distribution of trypanosomosis among dogs presented for haemoparasite screening at a tertiary veterinary hospital in south western Nigeria.

Abstract

Canine trypanosomosis poses a significant health risk to dogs in Nigeria, with potentially fatal outcomes. The geographical distribution of Glossina fly which serve as the primary vector for canine trypanosonosis is heterogenous. The spatial pattern of trypanosomosis incidence among dogs presented for haemoparasite screening a tertiary veterinary hospital located in south western Nigeria was investigated using 2354 archival laboratory case records spanning a twenty-year period (2004-2023). Each case was classified as either positive or negative for trypanosomosis based on presence or absence of trypanosome in blood specimens examined with light microscopy, respectively. Residential addresses from the laboratory forms were geocoded using Google Earth pro software, Kuldorff scan for spatial clusters of positive cases was accomplished using SatScan v9.7 assuming a binomial distribution, and mapping was done on QGIS version 3.24.1-Tisler. An overall prevalence of 1.87% for canine trypanosomosis was obtained, with a significant (primary) spatial cluster (Relative risk = 11.22; p-value = 0.000022) of 6.2 km radius situated in a densely vegetated residential region 5.9 km away from a major cattle market. Two statistically insignificant (secondary) clusters were also detected. The cluster locations suggest that environmental conditions favoring tsetse fly abundance contributed to the increased incidence of trypanosomosis among the dogs. Canine trypanosomosis control activities should be concentrated within the detected clusters. Prompt diagnosis and treatment should be administered for canine cases exhibiting clinical symptoms of trypanosomosis in these high-risk areas.