Serological and Molecular Detection of Toxoplasma gondii Among Slaughtered Domestic Ruminants in Gondar Town, Northwest Ethiopia

Abstract

BACKGROUND: Toxoplasma gondii is a globally prevalent zoonotic protozoan parasite that forms cysts and infects both animals and humans. Although there are reports on its seroprevalence, no comparative studies have validated the presence of this parasite in Ethiopian food animals. OBJECTIVES: This study assessed and compared serological and molecular techniques for the detection of T. gondii in slaughtered domestic ruminants in the study area. METHODS: A cross-sectional study was conducted from September 2019 to October 2020 by collecting 320 blood and corresponding tissue samples from purposively selected animals. The presence of this disease was identified using the latex agglutination test (LAT) and nested polymerase chain reaction (nPCR). SPSS version 25 with chi-square and logistic regression analyses was used to determine the relationship between associated risk factors and seropositivity of this disease. FINDINGS: The overall findings on the presence of this infection among slaughtered animals showed positivity rates of 180 (56.2%) through latex ATs, 68 (21.2%) in the first PCR run and 34 (10.6%) in the second PCR run. In latex ATs, positivity rates were recorded as 62% (62/100) in sheep, 52.7% (58/110) in goats and 54.5% (60/110) in cattle. The first PCR amplification detected positive cases in 34% (34/100) of sheep, 21.8% (24/110) of goats and 9.1% (10/110) of cattle. The second PCR amplification identified positivity in 20% (20/100) of sheep and 12.5% (14/110) of goats, whereas no positive cases were found in cattle. Seropositivity showed a significant association with sex and age in sheep and goats, origin in goats and breed and age in cattle (p value ≤ 0.05). A slight level of agreement was observed between latex agglutination and the first PCR test (Kappa = 0.230), whereas a fair agreement was noted between first PCR and nPCR (K = 0.338). Overall, nPCR demonstrated higher specificity (83.9%) compared to first PCR and the latex AT for detecting this disease. CONCLUSIONS: Thus, comparative detection confirms its presence in slaughtered food animals, aiding in early effective prevention and control for food consumption. Further research on pathogen genotyping is strongly recommended.