Molecular investigation of Toxoplasma gondii in oysters (Crassostrea spp.) sold on beaches in the State of Pará, Brazil.

The aim of this study was to detect Toxoplasma gondii DNA in oysters (Crassostrea spp.) sold on seven beaches in the State of Para, Brazil. According to the National Program for Hygiene and Sanitary Control of Bivalve Mollusks, 100 g of the edible part of mollusks is required to analyze contaminating microorganisms. In this study, 12 oysters were assumed to be equivalent to 100 g of edible parts when preparing each pooled sample. In total, 360 oysters were purchased from 30 vendors. From groups of 12 oysters purchased per vendor, 60 pooled samples were obtained, comprising 30 gill tissues and 30 gastrointestinal tracts. For molecular analysis, nested-PCR was conducted to amplify a 155-base-pair product of the B1 gene from T. gondii. All analyzed samples were negative for T. gondii. Our findings indicate that the oyster samples sold on the beaches in the State of Para were not contaminated by T. gondii.