Prevalence and Molecular Identification of Trypanosomes in Dogs in Enugu North Senatorial Zone, South East Nigeria

Abstract

Purpose: Dogs are of immense social, psychological and economic importance in Nigeria and are severely affected by African trypanosomosis. However, the prevalence of canine African trypanosomosis (CAT) in Nigeria is underreported and the identification of the parasites relies mostly on basic morphological characteristics under the microscope, which could be misleading. The present study was carried out to determine the prevalence and characterize trypanosomes isolated from dogs in South east Nigeria.

Methods: A cross-sectional survey was carried out to determine the prevalence and molecular identification of trypanosomes in dogs in Enugu North Senatorial Zone (ENSZ), South east Nigeria. Dogs (n = 450) were randomly sampled, their blood collected and some characteristics such as sex, breed, sampling location, season and age duly noted. The blood samples were screened for trypanosomosis using standard trypanosome detection techniques. Trypanosome-positive blood samples were spotted on FTA® cards for molecular identification using nested Tubulin-PCR, ITS-PCR, TgsGP-PCR, and DNA sequencing. Some hematological parameters of the dogs such as packed cell volume (PCV), total leucocyte count (TLC), red blood cell count (RBC) were also determined.

Results: Of the 450 dogs sampled, 51 dogs were positive for trypanosomes with a prevalence rate of 11.3% (95% CI = 0.087-0.146). Trypanosoma brucei was the predominant trypanosome species infecting dogs in the study area. T. congolense, T. evansi, and T. vivax were also identified. The prevalence of canine trypanosomosis was significantly associated with season (χ² = 13.821, df = 1, P = 0.0001) and the sampling location (χ² = 6.900, df = 2, P = 0.032) while sex, breed, and age were not. The PCV and RBC of the infected dogs were significantly lower (p < 0.0001) than those of the uninfected dogs.

Conclusions: CAT due to T. brucei is very prevalent in Enugu North Senatorial Zone, South east Nigeria and is associated with hematological changes. Our study also detected T. vivax in dogs in South east Nigeria which appears to be the first report of T. vivax in a dog in Nigeria.

Keywords: Canine African trypanosomosis; Dogs; Molecular identification; Prevalence; South east Nigeria; Trypanosomes.