Serological and molecular evaluation of Senecavirus A (SVA) in pigs from farrow-to-finish farms in Minas Gerais, Brazil

The emergence of Senecavirus A (SVA) as a causative agent of vesicular diseases in pigs is noteworthy, since it was identified in 2014 through outbreaks in Brazil. The SVA belongs to the Picornaviridae family and is a non-enveloped virus with the ability to adapt to the environment. As the virus's stability allows it to persist on farms post-outbreak, maintaining stringent biosecurity measures is crucial for effective control. This study aims to evaluate antibody response and viral RNA shedding in swine farms. Blood and fecal samples were collected from pigs in 2022 on farms that experienced outbreaks in 2015 and 2016. The sampled pigs were from farrow-to-finish farms without clinical signs of SVA obtained from five farms in Minas Gerais state, Brazil, covering all production phases: sows, farrowing, nursery piglets, growing, and finishing pigs. Real-time PCR and serum neutralization tests were conducted. Antibodies against SVA were detected in all production phases from four of the positive farms, with sows showing the highest antibody prevalence. Viral RNA was found in fecal samples from two farms, with the farrowing phase pigs exhibiting the highest viral RNA positivity. These findings indicate the presence of SVA infection on farms with no clinical signs, suggesting that the virus may have persisted following previous outbreaks due to its environmental stability. This study provides a comprehensive profile of antibody and viral RNA presence across different production phases, which may be applicable for informing biosafety measures.