Genotype distribution and risk factors of Toxoplasma gondii infection in animals of Trishal, Bangladesh

Abstract

Toxoplasma gondii is a globally significant parasite with no genotyping data available from Bangladesh. This study aimed to determine the genotype distribution and associated risk factors of T. gondii infection in animals in Trishal Upazila, Mymensingh district. From June 2020 to December 2023, a total of 170 samples from cattle, goats, sheep, cats, dogs, chickens, and rodents in the study area and examined using nested PCR targeting the B1 gene of T. gondii . Positive samples were genotyped by multilocus nested PCR-RFLP at ten genetic markers. Risk factor data were analyzed using logistic regression at the farm or owner level. The overall infection rate of 21.76% (37/170), with the highest prevalence observed in cyst samples from slaughtered cattle (42.9%) and cat feces (33.3%). Genotyping revealed a predominance of Type I and mixed genotypes (I/II, I/III) in cattle, cats, dogs, and rodents, while goats and sheep predominantly carried Type II or III. Chickens exhibited a mixed II/III allelic pattern with Type I alleles at the C22-8 locus. The use of pond/river water as a drinking source was a significant risk factor, with animals from these sources showing more than threefold higher odds of infection compared to tube-well users (p = 0.038). Backyard or small-holder farming, improper carcasses/offals/ placenta disposal, lack of rodent control, and unhygienic slaughter practices showed positive but non-significant associations with infection. This first report of T. gondii genotyping in Bangladesh highlights the presence of diverse and potentially virulent genotypes in food-producing animals, posing a notable zoonotic risk.