MILWAUKEE — A virus never before seen in the United States has killed millions of baby pigs in less than a year, and with little known about how it spreads or how to stop it, it’s threatening pork production and pushing up prices by 10 percent or more.
Scientists think porcine epidemic diarrhea, which does not infect humans or other animals, came from China, but they don’t know how it got into the country or spread to 27 states since May. The government is looking into how such viruses might spread, while the pork industry, wary of future outbreaks, has committed $1.7 million to research the disease.
The United States is both a top producer and exporter of pork, but production could decline about 7 percent this year compared with last — the biggest drop in more than 30 years, according to a recent report from Rabobank, which focuses on the food, beverage, and agribusiness industries.
Already, prices have shot up: A pound of bacon averaged $5.46 in February, 13 percent more than a year ago, according to the US Bureau of Labor Statistics. Ham and chops have gone up too, but not as much.
Farmer and longtime veterinarian Craig Rowles did all he could to prevent PED from spreading to his farm in Iowa, the nation’s top pork producer and the state hardest hit by the disease. He trained workers to spot symptoms, had them shower and change clothing before entering barns, and limited deliveries and visitors.
Despite his best efforts, the deadly diarrhea attacked in November, killing 13,000 animals in a matter of weeks, most of them less than two weeks old. The farm produces about 150,000 pigs each year.
Estimates of how many pigs have died in the past year vary, ranging from at least 2.7 million to more than 6 million. The US Department of Agriculture says the die-off has had a hand in shrinking the nation’s pig herd by 3 percent to about 63 million pigs.
Diarrhea affects pigs like people: Symptoms that are uncomfortable in adults become life-threatening in newborns that dehydrate quickly. The best chance at saving young pigs is to wean them and then pump them with clear fluids that hydrate them without taxing their intestines. But nothing could be done for the youngest ones except euthanasia.
PED thrives in cold weather, so the death toll has soared since December.
The first reports came from the Midwest, and the states most affected are those with the largest share of pigs: Iowa, Minnesota, North Carolina, and Illinois. The disease also has spread to Canada and Mexico.
Some states now require a veterinarian to certify that pigs coming in are virus-free, while China, which has seen repeated outbreaks since the 1980s, has asked the US Department of Agriculture to similarly vouch for animals shipped overseas.
Companies are racing to develop a vaccine, but the government has yet to approve one.