The WHO reported on Friday that high concentrations of the H5N1 bird flu virus strain have been found in raw milk from infected animals. The duration the virus can survive in milk remains uncertain. Avian influenza A(H5N1), identified first in 1996, has seen a dramatic increase in outbreaks since 2020, affecting not only birds but also a growing number of mammals.
The virus has caused the deaths of millions of poultry and has spread to wild birds as well as terrestrial and marine mammals. Last month, cows and goats were unexpectedly added to the list of susceptible animals, raising new concerns among experts. This month, U.S. health authorities reported a case in Texas where a dairy farm worker contracted bird flu from cattle, marking the first known instance of human infection from a cow. Wenqing Zhang, who leads the WHO's global influenza program, noted that this case indicates possible new transmission pathways for the virus, including bird-to-cow, cow-to-cow, and cow-to-bird.
Zhang also highlighted the growing number of cattle herds affected in various U.S. states, suggesting an escalation in mammalian infections. She confirmed that the virus has been detected in milk, emphasizing the need for further research into how long the virus remains viable in this medium.
The Texas health department has reassured the public that the cattle infections pose no threat to the commercial milk supply, as sick cows' milk is destroyed and pasteurization effectively eliminates the virus.
Zhang stressed the importance of adhering to safe food practices, particularly consuming only pasteurized milk and milk products.
