Serological survey of Paracoccidioidomycosis in sheep

The objective of this study was to evaluate the prevalence of antibodies against Paracoccidioides brasiliensis in sheep from Guarapuava, Paraná State, Brazil. The seroepidemiological study was carried out in 262 sheep. The samples were analyzed by ELISA and immunodiffusion test using P. brasiliensis gp43 and exoantigen as antigens, respectively. Initially, two sheep were immunized with P. brasiliensis to evaluate whether contact with the fungal cells could induce a humoral immune response against gp43 and exoantigen from P. brasiliensis. Both animals produced antibodies against gp43 and exoantigen, the main antigens used for diagnosis and seroepidemiology of paracoccidioidomycosis. A reactivity of 37% was observed to the P. brasiliensis gp43 antigen by ELISA although no reactivity had been observed by the immunodiffusion test. Sheep under extensive grazing system showed higher frequency of positivity to P. brasiliensis (P ≤ 0.05) than those under intensive and semi-intensive systems. These data suggest that sheep may be a useful epidemiological marker of P. brasiliensis presence in the environment and reinforce that contact with soil is an important risk factor for infection.