What swine disease costs: PRRS in the US and the global ASF threat

PRRS: a growing cost in the US

Iowa State University describes porcine reproductive and respiratory syndrome (PRRS) as the most economically damaging illness for swine producers. A study led by Dr. Derald Holtkamp at Iowa State University estimated that PRRS caused about $1.2 billion a year in lost production from 2016 to 2020 (Iowa State University, 2024). A 2012 study put annual losses for 2006–2010 at $664 million, so this is an increase of 80%.

The researchers broke down the $536 million increase:

• About $108 million came from changes in market prices, production costs, and the size of the US pig inventory.
• The other $428 million came from a larger share of herds being affected by PRRS and from bigger productivity differences between affected and unaffected herds.

The losses have also shifted toward growing pigs. Growing herds accounted for 55% of lost production in the earlier study and 68% in the new one. The new estimate drew on weekly herd-health data from a University of Minnesota swine health reporting program, plus productivity data collected from producers. Dr. Holtkamp presented the work at the International Pig Veterinary Society Congress in Leipzig, Germany, in 2024.

PRRS virus can travel on people, boots, and vehicles as well as through pig movements. Our summary of how pathogens move between farms covers a Minnesota experiment that traced PRRS virus from a truck wash to a simulated farm.

African swine fever: a global threat the US has kept out

African swine fever (ASF) is a deadly viral disease of domestic and wild pigs. It isn't a human health or food safety threat, and it has never been found in the United States (USDA). According to the USDA's Animal and Plant Health Inspection Service (APHIS), ASF has a 100% mortality rate and there is no vaccine for pigs (USDA APHIS, Pork Producers).

The disease is close to home. USDA notes that ASF is present in Haiti and the Dominican Republic (USDA, April 2026). Citing the World Organisation for Animal Health, APHIS reports that from January 1, 2022, through February 28, 2026, there were 13,879 ASF outbreaks in domestic pigs and 30,430 outbreaks in wild or feral swine across 74 countries and territories (USDA APHIS, Final Programmatic Environmental Assessment, May 2026).

The stakes for the US are high. USDA estimates that, as the world's second-largest pork exporter, the United States could face about $74 billion in losses over 10 years if ASF arrived (USDA, April 2026). USDA's advice to people who raise or work with pigs includes limiting visitors to animal areas, using dedicated clothing and shoes, buying pigs and feed from trusted sources, and reporting signs of illness right away.

US and international differences

• PRRS estimates above are for the US industry only. They don't describe losses in other countries.
• ASF has never been detected in the US but is active in many other countries. Studies from those places, like an investigation of ASF in a feed and swine production system in Vietnam (Gebhardt et al., 2022), show how systems manage the disease where it's circulating. That's a very different situation from the US today.

Why this matters for everyday biosecurity

Disease costs add up across the whole industry, but biosecurity happens one site and one visit at a time. The practices that matter most are often routine: who crosses onto the site, where vehicles go, what people wear, and what gets recorded. Your veterinarian and your biosecurity plan should guide your operation's priorities.