Cows might host both human and bird flus – Science News Magazine

Cows have entry portals for both human and bird flus. This new finding may mean that cattle could host both types of flus at once. The two viruses could then swap parts to create a new type of influenza, maybe even one that could cause a pandemic.

Cattle have three types of influenza A receptors entry portals viruses use to infect host cells veterinarian Charlotte Kristensen and colleagues report May 3 at bioRxiv.org. One portal is like a receptor that decorates human cells. Another is like that found in chickens. And the third resembles receptors from ducks.

One of those avian receptors may have allowed a virus from a wild bird to infect a dairy cow in Texas, leading to the current H5N1 bird flu outbreak in cattle.

Researchers have long thought cattle were resistant to influenza A, says Kristensen, of the University of Copenhagen. Some cows have been infected in lab studies, and there have been suggestions that cows might sometimes catch human seasonal influenza. But it surprised many experts when H5N1 bird flu was found in dairy cattle and in grocery store milk this spring (SN: 4/25/24).

In the new study, Kristensen and colleagues tested whether cows have receptors that bird flu viruses can use to infect their cells. Not only did the team find such entry portals but also found that the receptors, especially the duck version, were abundant in the mammary glands, at low levels in the respiratory tract and at very low levels in the brain. That fits with the description of the illness in cows, Kristensen says, which affects milk production but doesnt seem to make most cows very sick.

Its still unclear how an infection gets to the udder. Its possible the virus enters through the teat via contaminated milking machines. But none of the receptors are present in the ducts leading up to the milk-producing glands, Kristensen says. The virus might get to the mammary glands through the blood, but so far there are no reports of the virus in cows blood, she says.

These are just preliminary results, Kristensen says, but still important, because right now we really [dont] know very much about cattle and influenza viruses.

Questions or comments on this article? E-mail us atfeedback@sciencenews.org | Reprints FAQ

Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a masters degree in science journalism from Boston University.

We are at a critical time and supporting science journalism is more important than ever. Science News and our parent organization, the Society for Science, need your help to strengthen scientific literacy and ensure that important societal decisions are made with science in mind.

Please subscribe to Science News and add $16 to expand science literacy and understanding.

Link:

Cows might host both human and bird flus - Science News Magazine