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    Análise da frequência, viabilidade e caracterização genética do Toxoplasma gondii em diversos tipos de amostras provenientes de diferentes regiões do Brasil
    (Universidade Federal de São Paulo (UNIFESP), 2020-11-26) Costa, Deise Fialho Da [UNIFESP]; Mattos Junior, Rubens Belfort [UNIFESP]; Universidade Federal de São Paulo
    Objective: The goal of this study was to determine the frequency of Toxoplasma gondii (T. gondii) DNA in retinas from eye banks, fresh sausage, cured salami, and pork heart samples. The viability and genetic characteristics of T. gondii strains in pork heart samples was also analyzed. Methods: A total of 162 eyes were collected from eye banks of Manaus (n=60), São Paulo (n=60), Chapecó (n=26), and Joinville (n=16). The samples of 118 sausages (n=59) and salami (n=59) were collected from 8 different producers from Rio Grande do Sul; and 35 fresh pork heart samples were collected at a slaughterhouse in Erechim city. The retinas were analyzed macroscopically, collected, and DNA was extracted using the QIAamp DNA Blood Mini kit (Qiagen, Valencia, CA, USA), and the quantitative polymerase chain reaction (qPCR) was performed to identify T. gondii using B1 marker. After collection, sausage and salami samples were cut into small pieces, DNA was extracted using the DNeasy Mericon Food kit (Qiagen, Valencia, CA, USA), and the qPCR was performed using B1 marker to detect T. gondii. Parasite quantification for each sample was performed. In regard to pork hearts, DNA was extracted using the DNeasy Mericon Food kit (Qiagen, Valencia, CA, USA), and the qPCR was performed using B1 marker. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for genotyping the strain of T. gondii. Positive pork heart samples were digested and inoculated in mice for viability analysis. Results: Our study has shown a higher frequency of T. gondii DNA in the retinas from Joinville (25%) when compared to Manaus (5%). The retinas from São Paulo and Chapecó were qPCR negative for T. gondii infection. Macroscopic analysis showed retinal lesions compatible with toxoplasmosis in the following frequencies: Joinville (62.5%), Manaus (10%), São Paulo (6.7%), and Chapecó (15.4%). The frequency of T. gondii DNA among the total number of sausage and salami samples was 39% (46/118). Among these, we observed a higher frequency of positivity in the sausage samples (47.5%) when compared to the salami samples (17%). However, the mean parasite concentration was significantly higher in the salami samples (p=0.006). The results related to pork hearts showed that T. gondii DNA was detected in 25.7% (9/35) of the samples. The genotyping analysis revealed a new atypical T. gondii strain, assigned as TgPkErBra, in a sample of a pork heart. Out of 9 samples which were qPCR positive, 5 of them were intraperitoneally inoculated in mice and we observed that 4 of 10 mice (40%) presented clinical signs of T. gondii infection. Among 4 mice, 3 were qPCR positive for T. gondii in the lung, 1 in the liver, and 2 in the brain. Also, the histopathology analysis showed retinal disorganization, retinal detachment, inflammatory cell infiltration and fibrosis in 4 of 5 eyes analyzed. Conclusions: These studies confirmed the high frequency of toxoplasmic DNA presented in the retinas from eye banks, and in fresh and processed pork meats from Southern Brazil. Besides, the presence of T. gondii DNA in pork meat can contain live organisms and can be an important source of infections and a public health risk to be considered. Our results also demonstrate that pork meat can contain live T. gondii, and this result can be associated with the high frequency of toxoplasmosis in Southern Brazil. Furthermore, a new strain of T. gondii was found circulating in the same region.