April 30, 2009
Thursday

So far, it appears that American pigs are at more risk of catching "swine flu" from humans than the other way around. No cases have been found in pigs yet, while more than 100 human cases have been confirmed in the U.S., with many more suspected.

Farmers are being urged to take extra precautions to keep any possibly infected people away from their pigs, while scientists try to figure out if the animals are even susceptible to the virus.

"We know from the genetics that at some point back in time, the virus passed through a pig. But today, we don't know that it's in pigs at all, or even if it can any longer infect pigs,'' said Dr. Harry Snelson, a veterinarian in Burgaw, N.C. and communications director for the American Association of Swine Veterinarians.

"At this point, infected humans are more a risk to pigs than pigs are to humans, it would seem,'' Snelson said.

Some animal rights and food safety groups critical of large industrial pig farming operations are claiming that such practices may have helped the new virus get its start in Mexico. So far, international teams of scientists investigating the flu's origins haven't reported evidence of such a disease pathway.

But pork industries in general and pig farmers in particular are caught in a crossfire of confusion over the outbreak.

"It's unfortunate that this flu strain is being called `swine' flu, because the virus is a combination of viruses,'' said Dr. Bret Marsh, who oversees livestock health as Indiana's state veterinarian. "The reality is that swine flu hasn't been found in swine populations in the United States."

Federal and international health officials constantly reassure the public that eating pork is safe, that flu can't be spread by meat, that "this is not a food-borne crisis,'' as Agriculture Secretary Tom Vilsack told reporters earlier this week.

By Thursday, both the U.S. government and the World Health Organization had officially taken the swine out of swine flu, instead referring to it as " HINI influenza A.'' Homeland Security Secretary Janet Napolitano insisted to lawmakers that "after a few times, it does roll off your tongue.''

Beyond public relations problems with the flu's name, pig farmers face the challenge of making sure that "an infected human doesn't come on a farm and introduce the virus to pigs,'' Snelson said.

Larger, more sophisticated hog operations follow strict biosecurity procedures all the time, with workers wearing protective clothing and masks, washing carefully and staying away from herds if they or anyone in their family has any respiratory illness, among other things.

But DeHaven, a former administrator of the Agriculture Department's Animal and Plant Health Inspection Service, said pork producers will be better able to defend the herds once they know what happens when pigs are exposed to the virus.

Such "challenge testing" is, or soon will be, underway inside a 155,000 square foot Agriculture Department containment lab in Ames, Iowa, where health officials have shipped samples of the new virus. The facility includes such features as airtight walls, filtered air and treatment of all animal waste.

"Basically, they'll expose a group of pigs to the virus and see if they get it, and then a couple of days later, put them in with a new group of pigs, and see if the new ones come down it,'' said Dr. Gabriele Landolt, an assistant professor of veterinary medicine a Colorado State University who studies flu viruses in large animals using similar techniques.

"They'll probably do the same thing with turkeys, which have been found susceptible to this sort of strain in the past,'' Landolt added. "They should be able to have a pretty good handle on how easily this can be picked up and transmitted among the animals in a week or two."

DeHaven said it's likely, but not certain, that if domestic pigs can catch the new virus, wild hogs can too. That possibility is one reason that the large pork farms are refusing to allow any pigs that have spent time on smaller, outdoor farms. And it's also why health officials are urging people to avoid contact with feral pigs.

Meanwhile, pork producers continue to watch for any sign of disease in the pig houses. Any animal that shows signs of a flu-like illness is euthanized, necropsied and tested for flu at one of a dozen or more labs equipped to identify the new virus.

"There's also been an effort to go back and run the tests for the new strain on samples of animals that have died in the past several years,'' Snelson said. "But after doing hundreds of those, they still have not found that sequence in any pigs."

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Ketchikan, Alaska

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