US regains pseudorabies-free status in commercial swine after Iowa lifts last restrictions

The US has regained its pseudorabies-free status in commercial swine after Iowa lifted the last movement restrictions tied to an outbreak that marked the first detection of the disease in the US commercial swine industry in more than two decades, federal officials announced earlier this week.

The US Department of Agriculture's (USDA’s) Animal and Plant Health Inspection Service (APHIS) confirmed pseudorabies virus (PRV) antibodies at a small commercial swine facility in Iowa on April 30, 2026. According to officials, routine surveillance testing caught the case.² Investigators traced the source to 5 boars that had come from an outdoor facility in Texas, where animals also tested positive for the virus.²

Working with the Iowa Department of Agriculture and Land Stewardship, APHIS has since released all movement restrictions within the 2-mile surveillance zone established around the Iowa premises. All swine operations within that zone completed required testing, and no additional detections were identified.¹

The affected Iowa site came out of quarantine after the herd was depopulated, the premises were cleaned and disinfected, and a mandatory 30-day fallow period was completed.¹ APHIS subsequently submitted a final report to the World Organization for Animal Health, formally closing out the detection and restoring the country's pseudorabies-free status for commercial swine.¹

A disease eradicated from commercial herds, but not from feral swine

Pseudorabies is a contagious herpesvirus that primarily affects pigs, which are the only natural host of the virus.² The US commercial swine industry eradicated the disease in 2004 through a combination of culling infected animals, using marker vaccines, restricting animal movement, and preventing contact between domestic pigs and feral swine.²

Despite decades of successful control efforts, PRV persists in US feral swine populations, which continue to serve as a reservoir for the virus. Herds with outdoor access, including the Texas source herd linked to this case, face a greater risk of exposure, particularly in areas where feral swine are present.²

The virus can infect most mammals, although the USDA considers humans, horses, and birds to be resistant.¹ In nonswine species, infection is typically fatal, with clinical signs that may include severe itching, muscle tremors, seizures, and death. Those animals, however, do not transmit the virus further.

Consumer safety not affected

According to the USDA, the detection never posed a risk to consumer health or the safety of the commercial pork supply.¹ However, it may have limited short-term effects on US swine exports and swine germplasm.²

APHIS is continuing to work with international trading partners to lift export restrictions triggered by the Iowa case and is encouraging producers to maintain strong biosecurity measures, including double fencing for outdoor herds and sourcing pigs only from herds with validated pseudorabies-free status.^1,2

References

1. Iowa lifts remaining restrictions; United States is again free of pseudorabies in commercial swine. News release. US Department of Agriculture Animal and Plant Health Inspection Service. June 17, 2026. Accessed June 18, 2026. https://www.aphis.usda.gov/news/program-update/pseudorabies-response-update-iowa-lifts-remaining-restrictions-united-states#:~:text=With%20these%20actions%20complete%2C%20APHIS,contagious%20viral%20disease%20of%20pigs.
2. Bautista-Alejandre A. First US commercial pseudorabies case since 2004 confirmed in Iowa, linked to Texas herd. dvm360. May 19, 2026. Accessed June 18, 2026. https://www.dvm360.com/view/first-us-commercial-pseudorabies-case-since-2004-confirmed-in-iowa-linked-to-texas-herd