Several cases of avian influenza were announced in Minnesota and Iowa as well as in Wisconsin on Monday, signalling economic damage to commercial farms which will have to euthanize thousands of animals that may be affected to contain the outbreak.
A state of emergency was declared in Wisconsin on April 20 and Minnesota on April 23, and it was being discussed for Iowa.
Poultry and wild birds in the US Midwest have been infected with three highly pathogenic avian influenza viruses, which were carried by migratory wild birds unaffected by the virus, and caused thousands of bird deaths in poultry farms.
Since early March, the H5N2 virus has cost turkey and chicken producers in the US more than 13 million birds. Farmers only receive compensation if birds are euthanized as part of disease control efforts. For birds that die from the virus there is no indemnification nor is there likely to be insurance coverage.
In Iowa, five commercial poultry sites were quarantined on Monday after initial testing for a possible avian influenza outbreak affecting more than 6 million birds, and additional tests were being conducted for H5N2.
Should the tests come back positive, it would mean the influenza outbreak had affected more than 15.1 million birds from commercial farms in 13 states.
On the same day, US Department of Agriculture confirmed that a Wisconsin turkey farm with more than 1 million birds had tested positive. As of Monday, 55 farms in 18 Minnesota counties with more than 3 million birds were also affected by the H5N2 strain of avian influenza.
Of the three strains in the US, H5N8 originated in Asia and migrated with wild birds via the Pacific flyway. According to US Department of Agriculture data, It was identified in California and Idaho.
The other two strains, H5N2, the deadly strain, and H5N1, the less common strain, are highly pathogenic mixed-origin viruses.
The H5N2 strain, in addition to being discovered in Ontario, Canada, was identified in Arkansas, Idaho, Iowa, Kansas, Minnesota, Missouri, Montana, North Dakota, Oregon, South Dakota, Washington and Wisconsin.
There have not been any cases of human infection reported with the current H5N2 virus; however that does not eliminate all risk as bird flu viruses can mutate into versions that can jump to humans.
An expert in emerging infections at Columbia University, Dr. Stephen Morse, said: “Most of the time, these viruses don’t have human disease potential, but obviously you need to be very careful.”