Isolation, genetic and immunohistochemical identification of Toxoplasma gondii from human placenta in a large toxoplasmosis outbreak in southern Brazil, 2018.

The present study aimed to describe a molecular analysis of environmental and pork samples, the isolation, genetic identification and immunohistochemistry (IHC) of Toxoplama gondii from placenta and amniotic fluid from five pregnant women that miscarried during a toxoplasmosis outbreak in 2018, Santa Maria, Rio Grande do Sul. Environmental and pork samples were submitted to polymerase chain reaction (PCR); placenta and amniotic fluid samples to histopathology, IHC, mouse bioassay and PCR. All samples were genotyped by PCR-RFLP with 11 loci. Histopathologic and IHC were compatibles with toxoplasmosis. All pregnants were positive in PCR and bioassay, the genotypes were compared, and all were equal suggesting a same source of infection. Among the environmental and food samples, a sludge sample from a water tank and two porks samples were positive in PCR, and the genotypes were different from the pregnant women isolates. It is concluded that obtain and compare isolates is essential to elucidate outbreak source.

Isolation and molecular characterization of Toxoplasma gondii from placental tissues of pregnant women who received toxoplasmosis treatment during an outbreak in southern Brazil.

Toxoplasma gondii is a protozoan that has great genetic diversity and is prevalent worldwide. In 2018, an outbreak of toxoplasmosis occurred in Santa Maria, Brazil, which was considered the largest outbreak ever described in the world. This paper describes the isolation and molecular characterization of Toxoplasma gondii from the placenta of two pregnant women with acute toxoplasmosis who had live births and were receiving treatment for toxoplasmosis during the outbreak. For this, placental tissue samples from two patients underwent isolation by mice bioassay, conventional PCR and genotyping using PCR-RFLP with twelve markers. Both samples were positive in isolation in mice. The isolate was lethal to mice, suggesting high virulence. In addition, the samples were positive in conventional PCR and isolates submitted to PCR-RFLP genotyping presented an atypical genotype, which had never been described before. This research contributes to the elucidation of this great outbreak in Brazil.