Officials say H5N1 avian influenza has infected pigs in Oregon

Oregon state and federal officials confirmed Wednesday that H5N1 avian influenza has been found in pigs in Crook County. This is the first time that such a pig infection has been reported.

The strain of avian influenza virus in swine is slightly different from the strain known as B3.13 that is plaguing dairy cows in California and other states. Instead, it is called D1 and probably originates from wild birds that migrate along the Pacific Flyway.

Both strains are H5N1. They just followed slightly different evolutionary trajectories, which is reflected in their genetic sequences.

Scientists say finding influenza viruses in pigs, regardless of the strain, is concerning, especially now that human flu season has begun.

“This is the big event that everyone has been dreading,” said Rick Bright, a virologist and former director of the US Biomedical Advanced Research and Development Agency.

Health officials believe pigs are an efficient flu mixing bowl. Pigs are susceptible to both avian and human influenza viruses, potentially providing an opportunity for different viruses to exchange genetic material and pose a greater threat to humans.

“Experts and commentators have so far minimized the outbreak by saying, 'But it hasn't infected pigs yet.' Well, it seems that's the case now. “Another key ingredient arrives just in time to brew a pandemic virus, the seasonal human influenza virus,” Bright said.

He said it is important that federal authorities act quickly and transparently.

“We cannot continue to wait and see,” he said. “We all know how quickly this virus emerges and spreads. We must immediately remove it from these farms, increase all surveillance and develop an action plan for a larger response. We have to start. We can't afford to wait again. We have to act now.”

John Courseland, a former USDA veterinary epidemiologist, took a more cautious view.

According to officialsthe infected pig was one of five living on a small farm. All pigs were examined and euthanized. Results for two of the other pigs were negative, but the rest are pending. Additionally, federal officials said the samples detected only “low levels of the virus.”

Courseland said this suggests the virus may require close contact, such as shared water, to travel.

“I would be more concerned if it were transmitted by aerosols in a confined building,” he said, adding that the likelihood of an outbreak in a backyard herd with pigs acting as a mixing container “isn't that high, it's a bigger risk.” It is,” he added. [is] In commercial herds where influenza is more prevalent. ”

of oregon farmThe plant, located just east of Bend, is not a commercial operation, according to the U.S. Department of Agriculture. The animals were not destined for commercial food production.

As a result, federal officials say they have no concerns about the safety of the nation's pork supply. They also point out that properly cooking food and pasteurizing dairy products inactivates the virus.

The farm where the pigs lived was the same one where 70 infected “backyard birds” were tested and euthanized last week after H5N1 was detected. The farm has been isolated and the state Department of Agriculture is monitoring the area.

Oregon authorities said there were five pigs on the farm, but they did not live together. Three pigs, including the one that tested positive, were roaming freely on the farm. The other two pigs, called “teapot” pigs, were kept separately.

Both of these pigs underwent preliminary testing for the virus, but at least one of the two had a suspicious result. There, the pigs were killed and their bodies sent to the USDA National Veterinary Services Laboratory in Ames, Iowa. Those tests are pending.

Ryan Scholz, state veterinarian for the Oregon Department of Agriculture, said in a press conference Wednesday that these pigs were housed with infected chickens and likely contracted the virus from there, not necessarily from other pigs. He said he was not infected.

He said the three wandering pigs were large, but one was small enough to fit through the fence and likely interacted with the teapot pigs.

Other types of animals, including sheep and goats, were also present at the farm, but there were no signs of illness.

No one on the farm has shown any signs of illness.

However, Oregon Health Officer and state epidemiologist Dean Seidlinger would not say how many people were at the farm or whether they had been tested.

Both officials said the risk to the public remains low and food supplies are safe.

In the past two weeks, several outbreaks have occurred in commercial and backyard herds in British Columbia, Washington, and Oregon. California veterinarian Rebecca Jones told the Times on Tuesday that a small herd in her Santa Rosa backyard was also infected with the D1 strain.

The herd is not listed on the Department of Agriculture's website.

Additionally, two commercial poultry farms in Kings County, California and a backyard flock in Tulare County were reported infected on Tuesday. Again, the specific strain of H5N1 in these birds has not been identified.

However, it is likely to be a variant of this new wild bird.

“Based on recent diagnostic results, it is clear that migratory birds are moving this new 'D' genotype into the Pacific flyway,” said Brian, Emerging Disease Coordinator at the U.S. Geological Survey's National Wildlife Health Center. Richards said.

Scientists are frustrated by the lack of progress in understanding the genetic sequences of some recent outbreaks, especially as outbreaks continue in poultry, cattle and other animals.

On Wednesday, eight herds in Utah were confirmed to be H5N1 positive, but sequence data is not yet available.

According to the US Department of AgricultureSince March, 393 herds have been infected with H5N1 in 14 states, excluding Oregon. Almost half of those, 193, are in California.

Adding Utah's herds, which are not added to the USDA tally, there are 401 herds across 15 states.

Maurice Piteski, an associate professor at the University of California, Davis, whose research focuses on poultry health and food safety epidemiology, said when asked whether the introduction of new H5N1 strains could complicate the situation. “Yes,” he answered.

“This is the third year of migration, and the virus appears to be declining again through birds that have spent the summer in the Arctic and replaced the virus,” he said. “If it continues, it becomes more difficult to stop.”

He said a few years ago he was working on a computer model that could predict where the virus would appear as birds migrated south. He says it worked, and now people are asking him to develop something else.

“You can't do that,” he said. “It's too complex right now. It's present in urban wastewater, it's present in wild mammals. It's in dairy cows. It's in bird calls. It's in waterfowl and shorebirds. It's in marine mammals. …At a species level, at a geographic level, at a food security level, this has never happened before.