High seroprevalence of Toxoplasma gondii in goats in Jharkhand state of India

Toxoplasmosis, caused by Toxoplasma gondii, is an important food borne zoonosis worldwide. Although goat meat constitutes an important dietary protein source, improperly cooked meat is a potential source of infection to humans. Data on prevalence of toxoplasma in goat is scanty from India. Serological detection is the practical option for prevalence studies on T. gondii, as no biological stage of the parasite is present in the clinical materials from the intermediate hosts. The present study was undertaken in the Jharkhand state of India which is largely inhabited by economically weaker aborigine population, who depend largely on animal husbandry for livelihood. A total of 445 serum samples were collected for testing, which represented goats under intensive and free range system of rearing. T. gondii specific IgG antibodies were detected in 42.47% (n = 189) samples by rSAG1 based indirect ELISA. The seroprevalence data were analyzed in respect of age, sex, breed of the goats and altitude of the study area as well as rearing conditions of the animals to establish correlation, if any. Though age and sex of the animals had a direct correlation with infection, the same could not be established with the other factors. The sensitivity and specificity of the diagnostic ELISA were compared with IFAT, as well as with a commercially available ELISA kit. The rSAG1-ELISA had 92.66% sensitivity and 90.67% specificity with a positive predictive value of 86.77% and negative predictive value 94.92% when compared with IFAT, whereas when compared with the commercial ELISA kit, 87.50% sensitivity and 90.91% specificity with a positive predictive value of 91.30% and negative predictive value 86.96% were observed. Inter rater agreement (kappa) was calculated. rSAG1-ELISA showed good agreement with IFAT (kappa = 0.824) and commercially available ELISA Kit (kappa = 0.783). Receiver Operating Characteristics (ROC) curve analysis, revealed a larger area under curve (AUC) of 0.99 (95%CI, 0.97–1.0) when compared with IFAT as gold standard and a highest relative sensitivity 91.30 (95% CI 72–98.3) and specificity 1.0 (95% CI 85.2–100) for the cut off value of 0.6005. The present study revealed high seroprevalence of T. gondii in goats from Jharkhand, which has public health significance.