Molecular and serological diagnosis of Toxoplasma gondii infection in wild animals in the Pantanal in Brazil

Abstract The aim of this study was to report infection by Toxoplasma gondii in free-ranging mammals from Pantanal, as well as to compare the laboratory methods used to detect this parasite among native wildlife species. Blood samples from ocelots, crab-eating foxes, and coatis were included for serological analysis and molecular testing. In addition, tissue samples from wild rodents and jaguarundi were collected for molecular analysis. Seropositivity for T. gondii was 100% (2/2) in ocelots across all tests; ranged from 39.1% (9/23) by indirect hemagglutination assay (IHA) to 47.8% (11/23) by modified agglutination test (MAT) and indirect fluorescent antibody test (IFAT) in crab-eating foxes; and from 12.5% (3/24) by IHA to 20.8% (5/24) by MAT in coatis. The level of agreement between the serological techniques ranged from fair to moderate (Kappa=0.353–0.516). Furthermore, PCR analysis revealed the presence of T. gondii DNA in 100% (2/2 and 1/1) of the ocelots’ blood and jaguarundi’s brain, 30.4% (7/23) of the crab-eating foxes’ blood, 45.8% (11/24) of the coatis’ blood, and 23.8% (10/42) of the Thrichomys spp.’s tissues. Potentially atypical strains (incomplete genotyping) of T. gondii were identified by Restriction Fragment Length Polymorphism (PCR-RFLP) from ocelot, jaguarundi, and coati. These findings indicate the circulation of T. gondii among wild mammals at the Nhumirim Farm.