New versions of the H5N1 virus are increasingly adept at spreading. Suggestions to either let it rip in poultry or vaccinate the birds could backfire.

Tiny genetic alterations could help the bird flu virus enter cells in the upper respiratory tract, the C.D.C. said. But there is no sign that mutations are widespread in nature.

Although the avian flu (H5N1) virus may not be making the news as frequently, it is still working hard behind the scenes, ...

The patient in Louisiana who was hospitalized with severe bird flu illness was found to have a mutated version of the virus. Doctors react and share their concerns.

A new strain of bird flu has been detected on a duck farm in California. The World Organisation for Animal Health reported the outbreak of the new strain, H5N9, earlier this week.

Bird flu mutations raise fears of a broader outbreak Experts warn of inadequate testing by the CDC, which maintains the risk to humans “remains low.” ...

The avian flu virus isolated from a hospitalized teenager in Vancouver has mutations in key areas that could help the virus spread more easily in humans, scientists say.

From the outset of the Trump administration, bird flu, or H5N1 avian influenza, has flown rather conspicuously — and in fact ...

The U.S. Centers for Disease Control and Prevention said on Monday it has ended its emergency response for H5N1 bird flu, ...

Amidst an ongoing outbreak of a deadly bird flu virus in livestock, the US Department of Agriculture is doing more to prevent ...

BIRD flu has been detected in an English farm, it’s been announced. A case of the H5N1 bird flu was found in poultry in West Yorkshire. The Department for Environment, Food and Rural Affairs ...