(Wisconsin’s poultry farms are under a state of emergency, declared this past week by Gov. Scott Walker. National Guard forces are helping as avian flu spreads. As of late Tuesday, yet another Wisconsin turkey flock had been decimated with the H5 avian influenza virus – an 87,000-bird turkey flock in Chippewa County. As of that date, there were four known cases of the virus in Wisconsin, according to the Wisconsin Department of Agriculture, Trade and Consumer Protection. The latest count shows more than 7 million poultry affected across the Midwest, with numerous farms added to the list each day. Iowa has destroyed millions of chickens, and Minnesota, which has also declared a state of emergency, has also destroyed millions of birds. Sunday, the Minnesota National Guard was called up in an attempt to contain the epidemic.
Meanwhile the Centers for Disease Control and Prevention in Atlanta is scrambling to study the family of viruses to determine if a spread to humans is likely. Poultry workers are now being tested for the virus, and the CDC is recommending disinfecting all property and persons who have been around poultry. While transmission of avian flu from birds to humans has been rare in the United States, it has happened in Asia and Africa. The current strains are highly pathogenic strains of bird flu, meaning they are deadly to birds – and could possibly affect humans.
“It is possible that the process of genetic re-assortment could occur in a person who is co-infected with an avian influenza A virus and a human influenza A virus,” according to the CDC. “The genetic information in these viruses could re-assort to create a new influenza A virus with a gene from the avian virus and other genes from the human virus. Influenza A viruses with (the avian virus gene) against which humans have little or no immunity that have re-assorted with a human influenza virus are more likely to result in sustained human-to-human transmission and pose a major public-health threat of pandemic influenza. Therefore, careful evaluation of influenza A viruses recovered from humans who are infected with avian influenza A viruses is very important to identify re-assortment if it occurs.
“Although it is unusual for people to get influenza virus infections directly from animals, sporadic human infections and outbreaks caused by certain avian influenza A viruses and swine influenza A viruses have been reported.”
The CDC has isolated a strain of the H5N2 virus for potential use in a human vaccine, should one be needed. The names of these viruses indicate their origins. The H parts, which are highly pathogenic in poultry, originated in Asia, and the N parts come from North American avian flu viruses. U.S. Department of Agriculture officials say they are still seeing H5N8, the first virus, but they have now identified two strains of mixed-origin viruses, both of them highly pathogenic – H5N2 and H5N1. The latter virus has been found in a handful of recent cases. Both the USDA and the CDC are investigating the new mixed viruses to learn whether they could mutate and attack humans. In the past, while rare, bird flu has passed to humans. At that point, mutations become extremely dangerous.
Investigators are wearing full-protection suits with ventilators while at poultry farms cleaning and destroying birds. The CDC is also working to have the government’s stockpile of the antiviral drug Tamiflu released in order to be used for this outbreak. Hundreds of people who have been exposed to sick birds have been told to take Tamiflu as a precaution.
At the site of the newest outbreak in Chippewa County, the property was immediately quarantined and neighboring properties with poultry are being notified, according to the U.S. Department of Agriculture. Remaining birds will be destroyed to stem further spread of the virus. No poultry products will enter the food supply, officials said. USDA protocols, surveillance and testing procedures will take place at the properties near the affected facility to try to prevent the virus from spreading.
But the problem is that officials don’t know how the virus is being spread to more and more flocks. Researchers are considering numerous possibilities such as dust, wind, wild birds, human factors and more. The USDA’s Animal and Plant Health Inspection Service has increased the number of workers in the field, to almost 400.
The H5 avian influenza virus was first detected in Wisconsin April 13 at a commercial chicken flock in Jefferson County, with 180,000 egg-laying chickens destroyed. Since then, two more flocks have been infected in Barron and Juneau counties, bringing the total of affected Wisconsin birds to more than 310,000.
Backyard poultry owners and other poultry producers are encouraged to practice biosecurity measures and to take steps to prevent contact between their birds and wild birds. They also should monitor their flocks closely, and need to report sick or dead birds. The U.S. Department of Agriculture is working on a vaccine for poultry to counter the flu, as losses to poultry producers mount. USDA officials said the H5N2 virus could be a problem for the poultry industry for several years. The virus could reappear this fall when wild waterfowl that are believed to carry it fly south for the winter. Another concern is that it could spread to big poultry-producing states in the East.