CDC reports A(H5N1) ferret study results
CDC has completed its initial study of the effects of the A(H5N1) bird flu virus from the human case in Texas (A/Texas/37/2024) on ferrets, a model used to assess potential impact on people.
-The A(H5N1) virus from the human case in Texas caused severe illness and death in ferrets (100% lethal). A(H5N1) infection in ferrets has been fatal in the past. This is different from what is seen with seasonal flu, which makes ferrets sick, but is not lethal.
-The A(H5N1) virus from the human case in Texas spread efficiently between ferrets in direct contact but did not spread efficiently between ferrets via respiratory droplets ((1 in 3, or 33% were infected). This is different from what is seen with seasonal flu, which infects 100% of ferrets via respiratory droplets.
-These findings are not surprising and do not change CDC’s risk assessment for most people, which is low. The results do reinforce the need for people who have exposure to infected animals to take precautions and for public health and agriculture communities to continue to work together to prevent the spread of the virus to additional dairy herds and people.
Among numerous species used in the laboratory setting, only the ferret model is equally well suited for studying both the pathogenicity and transmissibility of human and avian influenza viruses.
