Cow Flu Crisis? Decoding the Dangerous Jump of H5N1 to Humans

Research on H5N1 influenza in U.S. dairy cattle shows the virus can cause severe disease in mice and ferrets but lacks efficient transmission through respiratory droplets. This finding suggests a limited potential for these bovine-derived viruses to cause widespread disease among mammals.

Experimental Findings From H5N1 Infection in U.S. Dairy Cattle
A series of experiments with highly pathogenic H5N1 avian influenza (HPAI H5N1) viruses circulating in infected U.S. dairy cattle found that viruses derived from lactating dairy cattle induced severe disease in mice and ferrets when administered via intranasal inoculation. The virus from the H5N1-infected cows bound to both avian (bird) and human-type cellular receptors, but, importantly, did not transmit efficiently among ferrets exposed via respiratory droplets.

The findings, published on July 8 in the journal Nature, suggest that bovine (cow) HPAI H5N1 viruses may differ from previous HPAI H5N1 viruses and that these viruses may possess features that could facilitate infection and transmission among mammals. However, they currently do not appear capable of efficient respiratory transmission between animals or people.