Transmissibility of H5N1 Bird Flu Virus from Cows to Humans

H5N1 Bird Flu Found in Milk for the First Time, WHO Issues Warning

Understanding the Transmissibility of H5N1 from Cows to Humans

The world’s gaze has shifted towards the threat of avian influenza, H5N1, with experts monitoring its alarming spread from birds to mammals, including humans. On a recent Friday, the World Health Organization (WHO) issued a stark warning about the virus’s presence in significant quantities in raw milk derived from infected cows. While the duration of the virus’s survival in milk remains uncertain, the discovery raises concerns about potential human transmission.

Historical Emergence and Transmission

The H5N1 avian influenza strain first emerged in 1996. Since 2020, the number of outbreaks among birds has skyrocketed. Additionally, mammals have increasingly fallen victim to the virus, leading to the deaths of tens of millions of poultry. Wild birds, land mammals, and even marine mammals are also being affected.

Last month, the list of susceptible animals expanded to include cows and goats. The outbreak of bird flu in cows has impacted at least 13 herds across six states in the United States, reports indicate.

Human Case and Cow-to-Cow Transmission

In February 2023, the United States reported the first case of a human infected with bird flu after exposure to infected cattle on a Texas dairy farm. This marked the second human case of bird flu in the United States.

During recent outbreaks, transmission between birds, from bird to cow, from cow to cow, and from cow to bird has been observed. Experts warn that this suggests the virus may have evolved to spread through new pathways.

Virus Concentration in Milk

The WHO announced that raw milk from infected cows contains “very high virus concentrations.” However, the exact length of time the virus can survive in milk is still under investigation.

The Texas health department assures that infected cattle pose no threat to the commercial milk supply as dairies are required to discard milk from sick cows. Additionally, pasteurization effectively eliminates the virus.

Human Infection and Recovery

Two individuals in the United States have tested positive for bird flu, with both experiencing mild symptoms. The first case involved a poultry worker in Colorado in 2022, while the second case involved a dairy worker who came into direct contact with infected cattle in Texas. Both individuals made full recoveries.

Concern and Implications

The WHO’s chief scientist has expressed concern over the risk of the virus spreading to humans. She emphasizes the need for increased surveillance and safe food practices to prevent human infection.

As H5N1 continues to adapt, experts are urging governments worldwide to take proactive measures to mitigate the threat. They emphasize the need for funding for vaccine research, enhanced surveillance of livestock and humans, and comprehensive emergency response plans.

Conclusion

The presence of H5N1 bird flu in raw milk highlights the evolving nature of the virus and its potential for human transmission. The WHO and health organizations globally are urging the public to consume only pasteurized milk and maintain good hygiene to minimize the risk of infection. With continued surveillance, research, and proactive measures, the world can collectively address the challenges posed by the H5N1 bird flu virus.