Abstract
The opossum has been recognized as an intermediate host for many parasites including Besnoitia spp., which is a protozoan that infects various mammals, including many wildlife species. A limited number of reports using serology, histopathology, and molecular assays have documented the presence of B. darlingi in opossums. In the present study, samples from three opossum species, including the Virginia opossum (Didelphis virginiana, n = 33) from urban/suburban areas of Florida, USA admitted to rehabilitation centers, and free ranging white-eared and black-eared opossum from two urban areas of Brazil (D. albiventris, n = 33; D. aurita, n = 34, respectively), were examined for antibody reactivity to Besnoitia spp. using indirect immunofluorescence (IFAT) and Western blot (WB) assays adapted for the detection of opossum antibodies. While 3/33 (9.1%) samples from Virginia opossum showed positive reactivity by both methods, none of the samples from the opossum from Brazil showed such reactivity. The three Besnoitia-seropositive samples were obtained from Virginia opossums clinically suspected to have besnoitiosis based on the appearance of diffuse skin lesions. These data support the further evaluation of serological testing in future studies of besnoitiosis in the opossum as well as a hypothesis of limited infection in the opossum of South Florida, USA, and southern and southeastern Brazil. Overall, the preliminary data has management implications for rehabilitation centers that commonly treat this species and research implications in the application of these assays in wildlife species.