Isolamento e genotipagem de Toxoplasma gondii de animais domésticos, animais silvestres e humanos do estado de Mato Grosso, Brasil

Abstract

Studies involving the genetic variability of Toxoplasma gondii are important, as they may suggest differences in the pathogenicity of each strain and help to understand the epidemiology of the infection. Thus, the present study aimed to isolate T. gondii through the mouse bioassay and describe the genetic diversity of strains isolated from domestic animals, wild animals and humans in the state of Mato Grosso. For this, fragments of tissue samples (heart, brain and lung) from 04 cats, 35 dogs, 115 wild animals, and amniotic fluid from 08 pregnant women, in addition to tissue samples (heart and brain) from 153 free-range chickens were collected from August 2017 to December 2019 and subjected to the mouse bioassay. In total, 01 isolates from cats, 09 from dogs, 10 from wild animals and 02 from women from five municipalities in the state of Mato Grosso were obtained, in addition to 51 isolates from chickens from six municipalities in the same state, which were subjected to the process of DNA extraction. The extracted DNA samples came from the lungs and / or brains of infected mice and from "primary samples" (aliquots of tissue homogenates from wild animals and amniotic fluids from pregnant women who were not successful in isolation) with the commercial kit DNeasy® Blood & Tissue®. The DNA was submitted to the Polymerase Chain Reaction (PCR) aiming at the amplification of a repetitive DNA fragment of 529 base pairs from the genome of T. gondii. All PCR positive samples were genotyped by the restriction fragment length polymorphism (RFLP) analysis technique with 11 markers [SAG1, SAG2 (5'3′SAG2 and alt. SAG2), SAG3, BTUB, GRA6, c22- 8, c29-2, L358, PK1, Apico and CS3]. We report for the first time isolates of T. gondii through the bioassay on Crax fasciolata, Dasyprocta azarae and Leopardus pardalis. In addition, the PCR-RFLP of all analyzed samples revealed 21 genotypes of T. gondii, 14 of which were previously described, including # 2 type III (n = 1), # 6 type BrI (n = 5), # 8 type BrIII (n = 12), # 11 (n = 3), # 14 (n = 3), # 19 (n = 1), # 41 (n = 2), # 99 (n = 1), # 108 (n = 1), # 109 (n = 4), # 116 (n = 1), # 140 (n = 4), # 166 (n = 13), # 190 (n = 2), and seven new genotypes, in addition of six isolates with mixed infection. The data are presented separately by article in the results topic. We highlight the presence of infection by the same genotype (# 14 and # 166) in humans, domestic dogs, free-range chickens and wild animals, suggesting a common source of infection in the biological cycle. These results confirm the high diversity of T. gondii strains in Mato Grosso, suggesting an importance to genotypes # 166 and # 8 for the region, as they were the most observed in the analyzed samples.