Isolation and molecular characterization of Toxoplasma gondii in sheep and goats in Grenada, West Indies

Sheep and goats are an importance source of meat in Grenada. The protozoan parasite, Toxoplasma gondii commonly infects small ruminants, often causing abortion and stillbirth. Toxoplasmosis is an important food borne zoonosis that is frequently acquired through consumption of undercooked meat. This study aimed to isolate T. gondii and determine its genotypes in sheep and goats in Grenada using PCR-restriction fragment length polymorphism (PCR-RFLP). We used a modified agglutination test (MAT) on blood or fluid from 51 goat and 40 sheep hearts purchased from a meat market to detect IgG antibodies. Nineteen (37.2%) of the 51 goats were positive with titers of 25 in 5 goats, 50 in 4 goats, 100 in 5 goats and 200 in 5 goats. Of the 40 sheep,13 (32.5%) were positive with titers of 50 in 9 sheep and 100 in 4 sheep. The hearts that tested positive were bioassayed in mice. T. gondii was isolated from nine goat hearts (designated TgGtGr1-TgGtGr9) and four sheep hearts (TgShGr1-TgShGr4). Genotyping of DNA extracted from mouse tissues using PCR-RFLP based on 11 genetic markers (SAG1, SAG2, alt. SAG2, SAG3, BTUB, GRA6, L358, PK1, C22-8, C29-2, and Apico) revealed two genotypes in goats: ToxoDB #2 (type III, n = 4) and #7 (n = 5). Sheep isolates showed the same genotypes, with two isolates each. This study demonstrates the presence of T. gondii in sheep and goats in Grenada and identifies two genotypes, suggesting limited T. gondii genotype diversity. These results have implications for food safety and public health, given the zoonotic potential of toxoplasmosis.