U.S. data showing a surprisingly large late-summer hog herd has done little to quell fears in rural America that a virus deadly to baby piglets could spread.
The U.S. livestock industry was anxiously awaiting Friday's release of the Agriculture Department's quarterly hogs and pigs report on the nation's swine inventory over the past three months, when cases of porcine epidemic diarrhea virus (PEDv) were swelling.
Most had expected the data to show that the virus had shrunk the herd compared to last year. Instead, it showed a total of 68.36 million head, slightly more than a year ago and higher than the 67 million that analysts had projected. But many in the livestock industry were cautious about the numbers.
There is no definitive data yet of how many animals have died in the U.S. from PEDv: Farmers are not required to report PEDv outbreaks.
Diagnostic veterinarians, producers and some livestock economists said they expected the virus to spread more rapidly as temperatures cool in the fall as piglets are being born. The virus is particularly deadly to very young pigs: average mortality rates range from 80 to 100 per cent.
"I read that report, and I'm more concerned than relieved," said Dr. Harry Snelson, spokesman for the American Association of Swine Veterinarians. "Week after week after week, we're seeing the same sort of picture: The virus is spreading. It's not slowing down."
Snelson said that if PEDv is able to survive in cold weather like other coronaviruses, "we're expecting to see a fairly dramatic increase in positive cases in winter time."
Kansas hog farmer Nathan Smith, whose operation lost at least US$1 million worth of livestock to a PEDv outbreak this summer, said he believes hog supplies have tightened up in some hard-hit markets, including Oklahoma and Kansas.
"I lost 15,000 animals this summer," Smith said. "I'm not alone."
As of the week of Sept. 15, there have been 644 confirmed cases reported in 17 states, according to federal officials. Each reported case could represent thousands of infected animals.
Focus on North Carolina
Researchers are watching North Carolina, the No. 2 hog-producing U.S. state, where 52 cases have been reported since the week of June 23. There, farm operators and diagnostic researchers say they are scrubbing down trucks, restricting visitors' access to buildings and testing the air for PEDv amid concerns about possible airborne virus transmission.
Many positive cases in North Carolina have come in sow barns, where piglet mortality rates have soared as high as 100 percent, said Dr. Tom Ray, director of the animal health livestock program for the North Carolina department of agriculture and consumer services.
Still, Ray said, "There are 52 cases and we've got 2,800 commercial operations in the state. So far, it's still pretty small numbers. But we're all still concerned about what's to come this fall and winter."
Agricultural economist Chris Hurt expressed caution about the numbers, and lack of evidence of total pig deaths.
"Yes, the numbers are a bit of a mystery. But the federal government, at least, has been asking all the big producers and surveying the small guys," Hurt said. "I would trust the USDA report."
The U.S. Department of Agriculture could revise its data when it finds out more, said independent market analyst Bob Brown. USDA has frequently adjusted its livestock numbers.
"There are a lot of questions about these numbers," Brown said. "There's something happening to the pigs and I think it has to do with PEDv."
-- P.J. Huffstutter is an agriculture reporter for Reuters in Chicago.