Seroprevalence of antibodies to non-structural protein of foot-and-mouth disease virus in vaccinated dairy cattle

Foot-and-mouth disease (FMD), a highly contagious viral disease of livestock, is endemic in Iran. To investigate the prevalence of antibodies against 3ABC non-structural protein (NSP) of FMD virus, a cross-sectional study was conducted on dairy cattle in eight cities of Kurdistan Province from May to September 2016. Serum samples (n = 283), were collected from cattle vaccinated with the recommended dose of a commercial vaccine and tested by a Competition enzyme-linked immunosorbent assay. Results showed the overall seroprevalence of antibodies against NSP of FMD virus in the vaccinated cattle was 22.30% (95.00% CI: 17.40 - 27.20%). The seroprevalence of antibodies was affected by geographical regions, with the highest seroprevalence related to the samples of vaccinated cattle in the cities of Marivan 95.00% (95.00% CI: 92.50 - 97.50%) and Saqqez 38.50% (95.00% CI: 32.80 - 44.20%). In terms of age, the highest seroprevalence of antibodies to FMD virus 26.70% (95.00% CI: 21.60-31.80%) belonged to ≤ 24-month-old cattle. These findings suggest that the presence of NSP antibodies in vaccinated cattle indicates the risk of infection with FMD virus serotypes circulating in the west of the province, so further studies with a larger sample size are recommended.