Evaluation of sampling and laboratory parameters contributing to successful isolation of senecavirus A1 from pigs

Senecavirus A1 (SVA; Picornaviridae, Senecavirus valles) infection causes an emerging infectious disease of swine that often leads to cutaneous vesicles on the snout and coronary bands and in the oral cavity of affected pigs, and causes epidemic transient neonatal loss in piglets. Virus isolation (VI) of SVA is required for viability testing, reference stock production, and monitoring virus evolution. We evaluated sampling and testing parameters leading to the successful propagation of SVA with a cross-sectional design based on 1,102 samples submitted to a reference laboratory. Logistic regression was used to evaluate the association between 16 variables and the outcome. When April was considered the reference month, the odds of SVA isolation failure were 17 and 100 times more likely during July and August, respectively. When foot samples were considered the referent, the odds of VI were 1.7 times more likely in unspecified samples. Compared to pooled samples, the odds of successful SVA isolation in individual samples were 8 and 45 times more likely in July and August, respectively. Laboratory parameters were not significantly associated with SVA isolation. The logistic model was moderately accurate (AUC = 0.68; 95% CI: 0.65-0.72%), suggesting that the model should be used cautiously for practical purposes. High environmental temperatures might negatively affect virus recovery. Using individual samples might improve SVA recovery when high ambient temperatures are recorded, as in the months of July and August.