Avian influenza update

Authors: Suarez, David; Spackman, Erica; Lee, Chang

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/13/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The largest animal disease outbreak in the U.S. was the highly pathogenic avian influenza outbreak in poultry, which has affected close to 100 million birds. Recently the H5N1 HPAI 2.3.4.4b virus was also reported in dairy cows. The virus can replicate to high titer in the mammary gland with large amounts of virus in milk. There has been considerable concern about the potential for live HPAI virus being found in milk, and surveys have identified live virus in bulk milk tank samples before pasteurization. Fortunately, available data supports that pasteurization effectively inactivates virus and a recent retail milk survey showed evidence of viral RNA, but no live virus. This supports that pasteurized milk is safe, but there is a potential for human exposure in consumption of raw milk and by the farm workers working with infected cows. Currently there have been 15 human cases, most had conjunctivitis and a or mild respiratory symptoms. There is concern that the ability to replicate in cows may increase the risk of human infections, but currently that has not been observed. Analysis of other avian influenza outbreaks in people have identified amino acid changes that are related to mammalian infection. Currently one mammalian amino acid marker has been found, but not the more common ones (PB2 627) found in other human infections. Because of the zoonotic risk, outbreaks are handled with extreme care and workers should be wearing personal protective equipment, including respiratory protection and safety glasses to help prevent exposure.