Seroprevalence of pythium insidiosum infection in equine in rio grande do sul, Brazil

An epidemiological survey was carried out by performing an Enzyme Linked Immuno Sorbent Assay (ELISA) test to determine the seroprevalence of Pythium insidiosum infection in equine in Rio Grande do Sul State (RS), Brazil. The serological study covered seven geographical regions of RS, classified according to the Instituto Brasileiro de Geografia e Estatística (IBGE). The samples were obtained from official veterinary service (Serviço Veterinário Oficial, SVO) linked to the Secretaria da Agricultura, Pecuária e Agronegócio of RS (SEAPA-RS) to proceed the investigation of equine infectious anemia in 2014. Samples were collected during the months of September and October of 2013, covering the seven geographical regions of RS, and totalized 1,002 serum samples. The seroprevalence for P. insidiosum in RS was 11.1% (CI_95% 9.23 to 13.22). The relative risk (RR) of the presence of antibodies anti-P. insidiosum was in the regions Southeast 11.17 (CI_95%, 4.65 to 26.8), Porto Alegre 4.62 (CI_95%, 1.70 to 12.55), Southwest 11.17 (CI_95%, 4.65 to 26.8) and Northwestern 3.72 (CI_95%, 1.52 to 9.09). The highest prevalence (69.1%) was observed in females with RR of 1.59 (CI_95%, 1.11 to 2.27). When the presence of dams was evaluated, the seropositivity was evident in 74.4%, presenting an association of 2.13 (CI_95%, 1.16 to 3.91) compared to farms without dams. In properties with veterinary assistance, the frequency of 72.7% and RR of 3.04 (CI_95%,, 1,85 to 4,98) of seropositivity were observed. Due to the importance of pythiosis in horse herds, this study highlights the presence of anti-P. insidiosum antibodies in horses in RS, Brazil.