Seroprevalence of Neospora spp. in horses reared in rural and urban areas in southern Brazil.

Protozoan Neospora spp. is known to negatively affect horses reared in rural and urban environments, being studied for causing abortion, neonatal mortality and central nervous system disorders in horses. This study aimed to verify the occurrence of anti-Neospora spp. antibodies in horses bred in rural and urban areas from southern Brazil and the risk factors associated with infection. The study consisted of 400 horses, which 241 were bred in rural areas and 159 in urban areas. The detection of serum anti-Neospora spp. antibodies was determined using Immunofluorescence Antibody Test (IFAT). The epidemiological questionnaire was applied to owners to determine the factors associated with the infection. The total seropositivity of the animals was 11% (43/400, 95% CI = 7,71-13,78%), distributed into 10% (24/241, 95% CI = 6,18-13,74%) in the rural and 12% (19/159, 95% CI = 6,91 - 16,99%) in the urban group (serum titer ≥ 50). There was no significant difference between rural and urban groups (p = 0.642; OD = 1.31; 95% CI = 0.663-2.58). Stallions and geldings in the rural group were four times more predisposed to presenting anti-Neospora spp. antibodies (p = 0.028; OR = 4.36; 95% CI = 1.164; 14.000). In conclusion, the breeding area is not correlated with seropositivity for Neospora spp. and stallions and geldings raised in rural environments from southern Brazil are more predisposed to infection. There are still poorly elucidated aspects of the infection by Neospora spp. in horses of different sexes, reared in different breeding environments that deserve our concern and require further studies.