Diagnostic strategies for the detection of Sarcocystis spp. and Toxoplasma gondii in bovine hearts from São Paulo, Brazil

Abstract

Foodborne parasitic zoonoses such as toxoplasmosis and sarcocystosis represent a public health challenge and an economic loss in the beef production chain, a sector in which Brazil lacks a specific laboratory monitoring program. This study aimed to detect Sarcocystis spp. and Toxoplasma gondii in bovine heart samples from the retail trade in the city of São Paulo, employing parasitological, histological, serological, and molecular diagnostic techniques. Parasitological research to identify tissue cysts formed by both protozoa was performed by microscopic methods. Histological research was performed on fragments of bovine heart tissue stained with hematoxylin-eosin. Nucleic acid detection was performed by Polymerase Chain Reaction (PCR), using specific primers for the cytochrome c oxidase subunit I (COX1) gene of Sarcocystis spp. and T. gondii B1 gene. Serology was performed by indirect Enzyme-linked immunosorbent assay (ELISA), using meat exudate as biological material. Our data demonstrated the presence of S. cruzi in 100% of the samples analyzed through conventional PCR targeting the COX1 gene, but T. gondii was not detected. Serology showed lower specificity, yielding false-positive results due to cross-reactivity. On the other hand, molecular methods showed greater sensitivity and specificity, allowing the identification of species of Sarcocystis spp. and the differential diagnosis with T. gondii . These findings provide promising contributions to the monitoring and sanitary control of beef, providing important diagnostic tools.