A ten years (2007-2016) retrospective serological survey for Seneca Valley virus infection in major pig producing states of Brazil.

Seneca Valley virus (SVV) is the etiological agent of vesicular disease in pigs, clinically indistinguishable of classical viral vesicular infections, including foot-and-mouth disease. The first outbreaks of SVV infection in Brazil were reported in 2014. However, it was not known whether the virus was circulating in Brazilian pig herds before this year. This study is a retrospective serological investigation of porcine health status to SVV in Brazil. Serum samples (n = 594) were grouped in before (2007-2013, n = 347) and after (2014-2016, n = 247) SVV outbreaks in Brazil. Twenty-three pig herds were analyzed, of which 19 and 4 were sampled before and after the beginning of SVV outbreaks, respectively. Two herds sampled after 2014 presented animals with SVV-associated clinical manifestations, while the other two housed asymptomatic pigs. Anti-SVV antibodies were evaluated by virus neutralization test. The results demonstrated that pig herds of different Brazilian geographical regions and distinct pig categories were negative to anti-SVV antibodies in sera obtained before 2014. Antibodies to SVV were detected only in serum samples obtained after 2014, particularly in herds with the presence of pigs with SVV-clinical signs. These results present robust serological evidence that the SVV was not present in the major Brazilian pig producing regions prior to 2014.