First isolation and genotyping of Toxoplasma gondii from free-range chickens on São Luis island, Maranhão state, Brazil, with a new genotype described.

Toxoplasma gondii is a protozoan with worldwide distribution that infects warm-blooded vertebrates, including humans. Toxoplasma is considered to be monospecific, but three classical clonal lineages (Types I-III) have been described, especially for isolates from North America and Europe. However, recently, several studies have shown that many isolates, particularly from South America, are different from the classic types and highly diverse, with the presence of specific clonal lineages and non-archetypal genotypes. In order to isolate and genotypically characterize T. gondii, 60 free-range naturally infected chickens (Gallus domesticus) from four municipalities on São Luis island, state of Maranhão, Brazil, were first serologically screened for IgG anti-T. gondii antibodies by means of the immunofluorescent antibody test (IFAT≥1:16). Heart and brain samples from seropositive chickens were bioassayed in mice. The isolates obtained from bioassaying were genotyped by means of PCR-RFLP (restriction fragment length polymorphism) using 11 markers and by microsatellites (MS) using 15 markers. The frequency of anti-T. gondii antibodies in the chickens examined was 25.0% (15/60). Five isolates of T. gondii were obtained and named TgCkBrMA1 to 5. Four genotypes were described. One of them is reported for the first time. No classic clonal lineages of types I, II or III were found, but the Brazilian clonal lineage BrI was identified. MS analysis revealed five genotypes. The results corroborate studies already developed in other regions of Brazil, thus indicating that T. gondii has high genetic diversity in Brazil.