RALEIGH — Nearly a third of the states 3,000 large commercial hog farms have been hit by a fast-spreading virus that usually kills every piglet it infects, and many farmers and veterinarians think its just a matter of time before the rest of the farms are hit.
Like human flu, porcine epidemic diarrhea (PED) virus thrives in cold, wet winter months. Recently it has been popping up on North Carolina farms at a rate of nearly 100 a week, according to data kept by state veterinarian David Marshalls office. The numbers may be low, though, since farmers arent required to report it.
The scientific community is still trying to figure out what this virus is all about, and the industry is working very hard trying to stop the spread, Marshall said.
PED is believed to have originated in China. It first appeared in the United States last spring in Iowa, reached North Carolina in late June and is now found in about two dozen states.
So far, no vaccine has been proven effective, though the situation was so serious that a vaccine was pushed out rapidly after being simply approved as safe, Marshall said. But natural resistance that appears in hogs at a given farm after the virus strikes does seem to be effective at preventing further massive outbreaks, he said.
North Carolina is the nations second-largest producer of hogs, with nearly 9 million on farms here.
Nationally, it looks like about 2 percent of the herd will be lost, said Kelly Zering, an associate professor and expert in farm economics at N.C. State University. Proportionally, though, farmers in North Carolina will absorb a bigger hit because it has a relatively large number of the sow operations that produce piglets. About a sixth of the nations sow operations are located here, Zering said.
Adults hogs immunity
Adult hogs are able to weather the virus and build immunity that sows can pass on to their young, so on many of the farms, the results are a gap of several weeks in production rather than the loss of the entire herd.
Indeed, getting infected helps the older pigs naturally inoculate the herds, said Harry Snelson, a Pender County veterinarian who is the spokesman for the American Association of Swine Veterinarians.
What were relying on is that the animals will develop immunity to it over time, and we do see that in some herds where theyve had the disease, said Snelson. And so we do know that can work over time, as long as you are not adding new, naive animals to the herd.
PED has shown an odd ability on a few farms to infect swine even after they develop immunity, he said. That may be because it is so easy to contract and vast amounts of the virus are present in some places, and those two things may simply overcome the resistance.
The virus doesnt pose any risk to humans. The losses may affect prices at the supermarket in a few months, but for now, farmers are bearing the main impact of losses that are well into the tens of millions.
Henry Moore, who farms in Sampson County near Clinton, said that he lost five weeks of production around 11,000 pigs which translates to about $400,000 in production costs wasted.
Producers have moved quickly to try to keep the virus off farms it hasnt hit, said Matthew Turner, a swine veterinarian for Prestage Farms, a multistate pork and turkey producer based near Clinton.
The biggest thing weve done is improve biosecurity protocols, like making sure someone visiting a farm hasnt recently been to another farm that has been infected with the virus, Turner said.
Among other things, theyre also thoroughly cleaning, drying and disinfecting trucks used to transport animals, and strictly enforcing already-standard rules such as requiring people to shower and swap clothes as they enter and leave farms.
Still, the virus seems to spread with unusual ease, so much so that many in the industry think it can move around for at least short distances on the air, perhaps hitchhiking on dust. Mainly, though, it spreads via even the tiniest trace of contaminated manure or feed being ingested by a pig or hog.
Moore said that he dealt with his outbreak in September by just writing off several weeks worth of litters, cleaning his farm thoroughly and inoculating his adult swine herd by putting the virus in their food. That ensured that they were thoroughly exposed.
He hasnt had any sick pigs since then.
Moore thinks the best scenario may be for every farm in the state to go through an outbreak, because if some dont and instead have a major flareup next year, it could send another wave back through farms that were already exposed.
Another scenario, he said, is that there could be issues for two or three more years during the cooler months, then the virus could fade away, as swine illnesses have done before.
Prestages Turner says his companys experience suggests this year may be the only big one for PED, but that the disease will never go away.
I think we will continue to see outbreaks periodically in farms, forever probably, he said. Well never get rid of it, I dont think, but the huge losses are going to be behind us.