Toxoplasma gondii infection in slaughtered domestic ruminants in Northwest Ethiopia: occurrence, bioassay and virulence assessment.

This study investigated the occurrence, isolation and virulence of Toxoplasma gondii in slaughtered domestic ruminants in Gondar, Northwest Ethiopia. Three hundred thirty-five blood samples (135 sheep, 50 goats, and 150 cattle) were purposefully collected from abattoirs and slaughterhouses. T. gondii antibodies were assessed using a commercial Toxo-Latex agglutination test. Tissue digestion with the pepsin enzyme was also performed on 39 heart muscles of seropositive animals, and viable T. gondii was isolated in white albino mice. As a result, the occurrence of T. gondii infection was 55.8%. T. gondii antibodies were found in 59.3% of cattle, 58% of goats, and 51.1% of sheep. The prevalence of T. gondii antibodies in sheep was significantly higher in females (χ2 = 4.55, p = 0.033) and adults (χ2 = 7.57, p = 0.006). Similarly, in cattle, the presence of T. gondii antibodies was associated with old groups (χ2 = 7.81, p = 0.005) and cross-breeds (χ2 = 6.30, p = 0.012). The overall viable T. gondii isolates in bioassayed mice were 38.5%, and the parasites were isolated from sheep (8/16), cattle (3/14) and goats (4/9) samples, with the majority of these isolates (87.2%) being avirulent. In conclusion, the presence of T. gondii antibodies and a high proportion of viable T. gondii in this study may indicate the parasite's prevalence and zoonotic importance in the study area. To plan control strategies, more research on the genotype and transmission dynamics of this parasite is required. Public education about T. gondii transmission routes and control methods is critical for preventing T. gondii transmission. © Indian Society for Parasitology 2022.