# Senecavirus A Incidence in U.S. Breeding Herds: A Decade of Surveillance Data

## TL;DR

This study analyzes Senecavirus A outbreaks in U.S. pig breeding herds over ten years, finding low but recurring incidence, with more cases in the Midwest during late summer and fall.

## Contribution

The study provides the first comprehensive decade-long analysis of SVA incidence and seasonality in U.S. breeding herds.

## Key findings

- SVA incidence remains low (<2.5% per year) in U.S. breeding herds.
- Outbreaks peak in the third and fourth quarters and are more common in the Midwest.
- The median time between outbreaks at the same site is 402 days.

## Abstract

Senecavirus A (SVA) is a virus that affects pigs and causes skin lesions that look similar to those caused by serious foreign animal diseases like foot-and-mouth disease. Because of this, every case requires careful investigation to rule out more severe threats. In 2015, a major outbreak of SVA raised concerns across the U.S. swine industry. However, since then, there has been little research on how often SVA occurs in U.S. pig farms. This study examines how frequently new SVA outbreaks happen in breeding herds to better understand how the virus spreads, as well as when and where it is most commonly detected. Our findings show that while SVA continues to affect U.S. breeding herds each year, it remains relatively uncommon, with only in a small proportion of herds affected. Outbreaks tend to happen more often in the second half of the year, with most cases occurring in the Midwest. Understanding these patterns can help farmers and veterinarians to improve prevention strategies and limit the impact of SVA on swine production.

Senecavirus A (SVA) is an endemic pathogen with ongoing relevance to the U.S. swine industry due to its clinical resemblance to foot-and-mouth disease (FMD) and its potential impact on animal health and trade. This study analyzes the incidence and geographic distribution of SVA outbreaks in U.S. breeding herds from January 2015 to December 2024. We used enhanced surveillance by combining diagnostic data from veterinary diagnostic laboratories and practitioners’ reports to assess SVA incidence, identifying temporal fluctuations and regional patterns. Our findings indicate that the cumulative incidence of SVA in U.S. breeding herds is low overall (<2.5% per year), with peak incidence observed during the third and fourth quarters of the calendar year. Outbreaks are more frequently reported in the Midwest. Our results suggest potential seasonality or regional factors influencing disease transmission. The median time interval between SVA outbreaks for sites experiencing more than one outbreak is 402 days. This study provides valuable insights into the current epidemiology of SVA in U.S. breeding herds, and highlights the need for continued monitoring and preparedness to prevent future outbreaks.