After laying dormant during the hot summer weather, the onset of cooler fall temperatures has increased the spread of a Porcine Epidemic Diarrhea Virus (PEDv) in North Carolina, the second-biggest hog producer, a state agriculture official said.
PEDv has spread to about 250 farms since June, Tom Ray, North Carolina director of livestock health, told Reuters on Thursday. While the disease continues to spread, Ray said it appears the rate of spread is slowing.
"We have about 250 positive swine farms," said Ray. "Probably about three of four weeks ago, we went from normally two to three cases in a week to three new reports in a day. That has actually started to go back to smaller numbers per week."
Ray said up to 150,000 sows could be affected. The disease is fatal to baby pigs, with the death rate in some litters up to 80 percent.
"It is definitely up," he said of the number of infected farms, however locating farms with the disease has been difficult because PEDv is a disease that is not required to be reported.
As of September 1, North Carolina had 8.7 million hogs, including a breeding herd of 870,000 head, according to the U.S. Department of Agriculture.
PEDv is not harmful to humans nor is it transmissible through pork. It has occurred in Europe and Asia, but this is the first year that it has been seen in the United States.
"You have a (hog) population that is naive because it has never been exposed to this disease before," said Ray. "Not having this virus before, you are going to have more losses initially."
"We're really holding our collective breaths because the virus has a tendency to peak in cooler weather in the winter," he said.
"It is definitely on the rise, but so is the immunity," he said of the number of cases. "But we had a slower rise in the last week or so than about two to three weeks ago."
The death of baby pigs from the disease will mean fewer market hogs next spring.
Heather Jones, senior agribusiness analyst at BBT Capital markets, estimates losses in North Carolina from the disease could cut weekly hog slaughter next spring by 1 to 1.5 percent.
Longer-term pig losses from the disease should decrease as herds become immune to it and the pork industry develops vaccines to cope with it, said Ray.
"Eventually it is going to be the new-normal production disease," he added.
(Additional reporting by Bob Burgdorfer; Editing by Eric Walsh)