Human, bird flu viruses can be transmitted through cattle: Study

Of particular interest is the abundance of these receptors, particularly the duck variant, in the mammary glands of cattle. This finding suggests a potential pathway for the transmission of bird flu to cows, offering insights into recent outbreaks such as the H5N1 bird flu incident observed in Texas dairy cattle.

While the precise mechanism of transmission to the udder remains a subject of inquiry, researchers speculate that it could occur through various routes, including contaminated milking equipment or bloodstream infiltration.

Despite uncertainties surrounding the exact mode of transmission, the presence of bird flu in grocery store milk has raised concerns about the safety of dairy products.

What can be done?

In response to these concerns, health experts emphasise the efficacy of pasteurisation in mitigating the risk of viral transmission through milk.

Presence of three types of influenza A receptors in cattle, akin to those found in humans, chickens, and ducks. (Representational)

Pasteurisation, a widely practised heat treatment process, effectively inactivates viruses, including influenza, rendering pasteurised milk safe for consumption.

However, the safety of raw milk, which has not undergone pasteurisation, remains a point of contention. Raw milk, while popular among certain consumers for its perceived health benefits, carries inherent risks, including the potential for transmitting infectious diseases. The US Food and Drug Administration cautions against the consumption of unpasteurised dairy products, including raw goat and sheep milk.

Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota in Minneapolis says that despite fears of human infection through milk consumption, “We have no evidence that humans have become infected from influenza A virus via ingestion.”

Past experiences with infected poultry have shown minimal transmission to humans, with health organisations categorising the risk of bird flu from milk as low.

Despite the reassuring safety measures in place, the discovery of dual entry portals for influenza in cattle has prompted further inquiries into the potential implications for public health.

Concerns persist regarding the possibility of genetic reassortment between human and avian influenza strains within cattle, potentially giving rise to novel viruses with pandemic potential. As such, ongoing surveillance and research efforts are imperative to monitor the prevalence and evolution of influenza viruses in livestock populations.

The recent findings underscore the interconnectedness of human and animal health, highlighting the need for a One Health approach suggested by the Centre for Disease Control and Prevention.