Isolamento e caracterização genotípica de isolados Toxoplasma gondii obtidos de galinhas de criação livre na ilha de São Luís - MA

Abstract

Toxoplasma gondii is a protozoan with a worldwide distribution that infects virtually all warmblooded vertebrates, including humans. Despite the Toxoplasma genus being considered monospecific, three classical clonal lineages are described for isolates mainly from North America and Europe. However, some researches have shown that many isolates that were found, particularly in Brazil, are different from the classic types, with the presence of specific clonal lineages and atypical genotypes. In order to isolate and characterize genotypically strains of said protozoan found in free-range chickens naturally infected in the municipalities of the Sao Luis island – MA, 60 chickens (Gallus domesticus) were undergone to serologic screening by Immunofluorescence Antibody Test (IFAT). Heart and brain samples from seropositive chickens were submitted to bioassay in mice. The isolates obtained from bioassay were genotyped by Polymerase Chain Reaction, method Restriction Fragment Length Polymorphism (PCR-RFLP), using the markers SAG1, 3'SAG2, 5'SAG2, alt .SAG2, SAG3, BTUB, GRA6, c22-8 , c29-2, L358, PK1, Apico and CS3. The frequency of T. gondii infection in examined chickens by IFAT was 25.0% (15/60). Five isolates of T. gondii were obtained and four different genotypes were described. One of them was not recorded in the literature, thus, first isolated in this study. Classic clonal lineages of type I, II and III were not found, but the Brazilian clonal lineage BrI was identified. The results corroborate with studies already developed in other regions of Brazil, indicating a high genetic diversity of T. gondii. Key words: Toxoplasma, PCR-RFLP, bioassay, chickens.