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. •There was a big toxoplasmosis outbreak with high pathogenicity for pregnant womentriggering abortion and fetal mortality.•Inoculation of the placenta macerate, besides being simpler, brought a faster result than peptic digestion.•Genotyping can help elucidate the source of toxoplasmosis outbreaks.