Researchers at the University of Wisconsin-Madison have discovered that the H5N1 virus, better known as avian flu, can make mice and ferrets sick when they come into contact with contaminated cow’s milk. These results, published in the famous journal Nature on July 8, shed new light on the way the avian flu virus spreads and the risks it represents for humans.
H5N1 virus, transmissible to humans
Avian flu is a highly contagious viral disease that affects poultry such as chickens and turkeys.
- The H5N1 strain has recently crossed the species barrier to spread widely among cattle and in particular in several dairy cow farms in the United States.
- The H5N1 strain can be transmitted from animals to humans. In principle, humans must have been in direct contact with infected poultry or cows to contract the disease.
- An American study carried out on mice and ferrets shows that raw cow’s milk and raw meat contaminated with the H5N1 bovine strain can transmit the disease.
Avian flu: contamination by raw milk and raw meat
Researchers have found that mice can get sick even from drinking small amounts of contaminated raw milk. This indicates a real risk to people who come into contact with raw milk, particularly in industries that process cow’s milk. Consumption of unpasteurized milk contaminated with the H5N1 virus could result in direct exposure to the virus.
The team also found that the virus could spread to the mice’s muscles as well as their mammary glands. The female was then able to transmit the disease to her young via her infected milk.
These results therefore reveal a risk in consuming unpasteurized cow’s milk or raw or insufficiently cooked beef.
Can bird flu be spread through the air?
The research team also tested whether the H5N1 virus could spread through the air among ferrets. Ferrets are often used as a reference for studying the spread of viruses in humans because their respiratory symptoms are similar to those of humans with the flu. For this study, researchers placed infected ferrets near uninfected ferrets, but without direct contact. During the experiment, none of the four exposed ferrets became ill and no viruses were detected in their bodies. However, one of them produced antibodies against the H5N1 virus. Yoshihiro Kawaoka, professor of pathobiological sciences and lead author of the study, said: “The fact that antibodies were found shows that the virus can indeed spread through the air, but to a limited extent.”
Can the H5N1 virus mutate and become dangerous for humans?
One of the worrying conclusions of the study is that the H5N1 virus has a great capacity to mutate over time, but also to exchange genes with influenza viruses such as human flu. This means the virus can adapt to human hosts, posing a potential risk for the future. Although only a limited number of cases of H5N1 transmitted from animals to humans have been reported so far, this suggests that the virus may be capable of undergoing mutations that facilitate human-to-human transmission. It is therefore essential for public health to continue to closely monitor and contain the virus.
Sources :
https://scitechdaily.com
https://www.nih.gov
https://www.fda.gov
Last updated: October 2024
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