Location: Virus and Prion ResearchTitle: Efficacy of an inactivated Seneca Valley virus vaccine in pregnant sows
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/6/2019
Publication Date: 11/27/2019
Citation: Buckley, A.C., Lager, K.M. 2019. Efficacy of an inactivated Seneca Valley virus vaccine in pregnant sows. Meeting Abstract. p. 36.
Technical Abstract: Introduction Senecavirus A (SVA), commonly known as Seneca Valley virus (SVV), is a causative agent of vesicular disease in swine that is clinically indistinguishable from foot-and-mouth disease (FMD). Due to the severe consequences of FMD entering a FMD-free country, a foreign animal disease investigation must be performed every time a vesicular lesion is observed. These investigations have economic ramifications especially for the state and federal government. A large portion of the investigations have been centered at sow slaughter facilities, with some facilities requiring investigations weekly. Having an effective SVV vaccine would be a valuable tool for the swine industry to improve swine health and reduce disruptions related to foreign animal disease investigations. Materials and Methods Part 1: Pregnant sows were randomly placed into 4 groups: Group 1 (vax + challenge, n=4), Group 2 (vax + sham, n=2), Group 3 (no vax + challenge, n=2) and Group 4 (no vax + sham, n=2). Around 70 and 90 days of gestation Groups 1 and 2 were vaccinated intramuscularly (IM) with 2 mL of whole-virus inactivated SVV (2015) with an oil-in-water emulsion adjuvant. Sows were intranasally challenged around 104 days of gestation (0 dpc) with 5 mL of a 2018 SVV isolate (107 TCID50/mL, challenge) or media (sham). Sows were rectal swabbed daily for the first 10 dpc and checked for vesicular lesions. Sows were bled at -35, -14, 0, 4, 7, 14, and 21 dpc. Part 2: At farrowing, colostrum was collected and piglets were bled prior to suckling. Piglets (3-5 days old) from Group 1 and 4 were challenged orally with 2 mL of SVV (107 TCID50/mL, challenge) while Group 2 and 3 piglets were given media (sham). Piglets were bled and rectal swabbed on 0, 4, 7, 14, 21 dpc. Rectal swabs and serum were tested for SVV RNA by PCR and the antibody response was determined by virus neutralization (VN) assay. Results Results are pending as sows are due to farrow in September of 2019. Previous research has demonstrated immunity in sows given this vaccine and challenged with a 2015 SVV isolate (106 TCID50/mL). Unpublished work has also demonstrated efficacy of this vaccine in growing pigs. We hypothesize the whole-virus inactivated SVV vaccine will provide protection against clinical disease, prevent viremia, and reduce or eliminate shedding of virus in feces in sows after challenge with a 2018 SVV isolate. We also hypothesize that vaccinated sows will pass SVV immunity on to their offspring and piglets challenged with a 2018 SVV isolate will be protected. Conclusion An effective vaccine could have a positive impact on welfare in the swine industry and reduce the economic burden of foreign animal disease investigations.