Seroepidemiology of ovine toxoplasmosis and neosporosis in breeding rams from Rio Grande do Sul, Brazil

This study determined the prevalence of ovine toxoplasmosis and neosporosis and the risk factors associated with the development of these diseases in breeding rams from the State of Rio Grande do Sul (RS), Southern Brazil. Serum samples (n = 1,800) from breeding rams maintained on 705 sheep farms from seven mesoregions were evaluated serologically to detect anti-IgGToxoplasma gondiiby indirect ELISA and anti-IgGNeospora caninumby the indirect immunofluorescence assay (IFA). The prevalence ofT. gondiiwas 33.05% (595/1,800); seropositivity toN. caninumwas 18.44% (332/1,800). Additionally, there was simultaneous seropositivity (8.94%;161/1,800) toN. caninumandT. gondii. The variables size of the property (<500 ha) (Prevalence Ratio, PR = 1.36); breeding system (semi-intensive/intensive) (PR = 1.23); and natural mounting without control (PR = 1.50) were considered as risk factors for the occurrence ofT. gondii. Size of the property (<500 ha) (PR = 1.58) and natural mounting without control (PR = 2.32) were risk factors associated with the prevalence ofN. caninumin rams. Additionally, separation of ewes prior to parturition was considered as a protective factor for the occurrence ofT. gondii(PR = 0.82) andN. caninum(PR = 0.74). These results demonstrated that these two parasitic disease agents are endemic in rams throughout all regions of RS.