Efficacy of an inactivated Senecavirus A vaccine in weaned pigs and mature sows

Authors: Buckley, Alexandra; Lager, Kelly

Submitted to: Vaccine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2022
Publication Date: 2/16/2022
Citation: Devries, A.C., Lager, K.M. 2022. Efficacy of an inactivated Senecavirus A vaccine in weaned pigs and mature sows. Vaccine. 40(12):1747-1754. https://doi.org/10.1016/j.vaccine.2022.02.018.
DOI: https://doi.org/10.1016/j.vaccine.2022.02.018

Interpretive Summary: Senecavirus A (SVA), commonly known as Seneca Valley virus (SVV) is a causative agent for vesicular disease in swine. It has been found across the globe including the United States, Brazil, and China. Clinical disease caused by this virus is identical to foot-and-mouth disease virus (FMDV). Since FMDV has the potential to cause severe economic consequences in FMDV-free countries, those countries are on high alert for signs of vesicles in swine and an investigation is performed to rule out the presence of FMDV if observed. In countries where SVA cases have continued to occur, investigations and testing can cause a burden on personnel and resources. In addition, with the consistent occurrence of vesicular lesions in swine, veterinarians and producers in the swine industry may become complacent in assuming lesions are due to SVA infection. If FMDV were to enter the country and remain undetected for a period, the consequences could be devastating for not only the swine industry, but also animal agriculture and the economy. In this study both weaned pigs and mature sows were given two doses of the vaccine intramuscularly three weeks apart and challenged intranasally two weeks after the second dose. Non-vaccinated pigs challenged with SVA developed clinical signs of disease, replicated virus, and developed a neutralizing antibody response. Vaccinated pigs did not develop vesicular disease, had limited rectal shedding, and had robust neutralizing titers after two doses of vaccine. Piglets suckling immunized dams and challenged with SVA at 3-6 days-of-age had neutralizing titers prior to challenge and did not replicate or shed virus. This work demonstrated that an inactivated SVA vaccine was able to prevent the development of vesicular lesions and reduce viral shedding. An effective SVA vaccine would be a valuable tool for the swine industry that could have a positive impact on welfare and reduce the economic burden of investigating vesicular disease cases.

Technical Abstract: Senecavirus A (SVA), commonly known as Seneca Valley virus (SVV) is a causative agent for vesicular disease in swine. It has been found across the globe including the United States, Brazil, and China. Clinical disease caused by this virus is identical to foot-and-mouth disease virus (FMDV). Since FMDV has the potential to cause severe economic consequences in FMDV-free countries, those countries are on high alert for signs of vesicles in swine and an investigation is performed to rule out the presence of FMDV if observed. In countries where SVA cases have continued to occur, investigations and testing can cause a burden on personnel and resources. The objectives of this study were to test the efficacy of a whole-virus inactivated SVA vaccine against challenge in nursery-aged pigs, mature sows, and to assess the protection of passive maternal immunity generated by immunized dams. Pigs were given two doses of the vaccine intramuscularly three weeks apart and challenged intranasally two weeks after the second dose. Non-vaccinated pigs challenged with SVA developed clinical signs of disease, replicated virus, and developed a neutralizing antibody response. Vaccinated pigs had robust neutralizing titers after two doses; and after challenge, did not develop vesicular disease and had limited rectal shedding. Piglets suckling immunized dams and challenged with SVA at 3-6 days-of-age had neutralizing titers prior to challenge and did not replicate or shed virus. An efficacious vaccine could improve swine welfare and reduce the economic consequences of continued foreign animal disease investigations.