This strain was found to be deadly for ferrets in experiments, while seasonal flu only makes them sick.

Ferrets are commonly used to study influenza virus transmission and assess public health risks.

In the study, the bird flu virus spread easily among healthy ferrets in direct contact with infected ones, but was less efficient in spreading through respiratory droplets.

The CDC has stated that bird flu viruses, which have infected over 80 dairy herds in 11 US states since March, may need to change in order to spread efficiently through the air via coughs and sneezes.

Scientists are monitoring the virus for signs of adaptation to human transmission.

Reuters reported that US and state agencies are planning research into potential respiratory spread of bird flu among dairy cattle to guide containment efforts and minimize human exposure.

Respiratory spread could increase the virus's opportunity to evolve and potentially become more transmissible among humans.

Since March, the US, Mexico, and Australia have reported a total of five human cases of different versions of H5 bird flu.

Three mild cases of COVID-19 were reported in US dairy workers, with two experiencing conjunctivitis and the third having respiratory symptoms.

A man in Mexico, who had pre-existing conditions, died from multiple factors related to COVID-19.

New findings in ferrets do not change the CDC's low risk assessment for most people, but emphasize the importance of precautions for those with animal exposure and continued efforts to prevent the virus's spread to more herds and people.