Deadly Spillover: H5N1 Bird Flu Jumps from Cows to Cats on Texas Dairy Farm

Deadly Spillover: H5N1 Bird Flu Jumps from Cows to Cats on Texas Dairy Farm

In a concerning development in the ongoing global outbreak of highly pathogenic avian influenza (HPAI) H5N1, researchers have documented the first known case of the dangerous virus spreading from cows to cats on a Texas dairy farm.

The outbreak, first detected on March 16, began with cows on the farm showing symptoms of a mysterious illness, including a dramatic drop in milk production and changes to the consistency and color of their milk. Within a day, cats that had consumed the raw milk from the infected cows also fell ill, developing a range of severe symptoms including depression, loss of coordination, and blindness.

Tragically, over half of the farm's 24 cats succumbed to the flu within just a few days. Postmortem analysis revealed that the cats had H5N1 not only in their lungs, but also in their brains, hearts, and eyes – a pattern similar to what has been observed in cats experimentally infected with the virus.

The researchers, who published their findings in the journal Emerging Infectious Diseases, concluded that the contaminated milk was the most likely source of the cats' fatal infections. Genetic data showed an almost exact match between the virus found in the cows, their milk, and the sick cats.

"Our findings suggest cross-species mammal-to-mammal transmission of HPAI H5N1 virus and raise new concerns regarding the potential for virus spread within mammal populations," the authors wrote.

This outbreak on the Texas dairy farm comes amid a broader surge in H5N1 infections among mammals, beyond the virus's typical avian hosts. Since 2022, the U.S. Department of Agriculture has documented the presence of H5N1 in over 200 mammals, including big cats, seals, mountain lions, and even cows.

The discovery of H5N1 in dairy cows is particularly troubling, as the virus has now demonstrated the ability to contaminate a food product consumed by humans. While commercial milk is still considered safe due to pasteurization, the FDA has detected genetic traces of H5N1 in roughly 20% of commercial milk samples, suggesting the virus may be more widespread among the country's milk-producing herds.

Experts warn that this development underscores the need for increased surveillance of HPAI viruses in domestic livestock, as well as greater public awareness of the dangers of consuming raw milk. Unlike other influenza viruses, H5N1 has shown the ability to infect organs beyond the respiratory system, as seen in the fatal cases among the Texas farm's cats.

"The recurring nature of global HPAI H5N1 virus outbreaks and detection of spillover events in a broad host range is concerning and suggests increasing virus adaptation in mammals," the study authors cautioned.

As the global fight against the H5N1 outbreak continues, this latest incident on the Texas dairy farm serves as a sobering reminder of the virus's potential to cross species barriers and wreak havoc in unexpected ways. Vigilance and proactive measures will be crucial to mitigate the risks and prevent further deadly spillovers.