Seroepidemiology, molecular detection, and isolation attempts of Toxoplasma gondii in dairy goats from Rio de Janeiro, Brazil.

Abstract

Goats are the one of the most susceptible domestic species to toxoplasmosis affecting animal health and production. The present study aimed to determine the seroprevalence of T. gondii infection in dairy goats from Rio de Janeiro, Brazil, as well as to evaluate associated risk factors, parasitic DNA detection in raw goat milk samples, and attempts to isolate the parasite from raw goat milk samples. Between October 2020 and December 2022, blood samples were collected from 460 goats, and 220 milk samples were taken from goats raised in the Rio de Janeiro state, Brazil. The serum samples were tested for anti-T. gondii IgG antibodies using IFAT. The milk samples were tested for parasitic DNA detection using nPCR, and attempts were made to isolate the protozoan in mice. For risk factor analysis, the farmers answered a semi-structured questionnaire covering various epidemiological variables. Overall, 24.1% tested positive for anti-T. gondii IgG in serum samples. Risk factors included farm location, age group, rearing system, presence of cats, grazing, and access of cats to water sources. In nPCR, 38.6% were positive, but none were positive in the bioassay. However, 3.2% of the mice inoculated with goat milk seroconverted. This study found that the exposure of dairy goats in Rio de Janeiro to T. gondii is driven by ineffective management practices in preventing and controlling the parasite in these animals. Moreover, despite the detection of parasitic DNA in raw goat milk, the shedding of viable parasites in milk from naturally exposed goats appears to be low.