Experts: Bird Flu Outbreak Spreading, But Not Expected to Become Pandemic

By Jay Kumar

In a January 10 media briefing, experts from the Infectious Diseases Society of America (IDSA) said that despite a recent death attributed to the H5N1 bird flu, the virus poses a low public health risk and is not expected to become a pandemic.

That said, officials are monitoring the situation closely as it develops. In the U.S., the bird flu has been detected in dairy cattle, wild birds, poultry flocks, and mammals. There have been 66 confirmed human cases of bird flu in the U.S. and one death associated with the virus, but there has been no person-to-person spread of H5N1 detected yet.

Shira Doron, MD, FIDSA, Chief Infection Control Officer at Tufts Medicine Health System, told reporters that there have been three notable recent cases of bird flu: a teen in Canada, an older person in Missouri who had already been hospitalized for something else, and the first bird flu death of a man in Louisiana who was over 65 and had underlying medical conditions.

Still, Doron noted, “the strains are poorly suited for pandemic potential” and are well-matched with a couple of candidate vaccines.

For the virus to be more efficient, “a number of mutations would have to occur,” she said. The virus would have to be better at binding to humans for it to become a pandemic, Doron added. Although she noted that in the Canadian case, the virus was found to have mutated.

There is still much that public health officials don’t know about H5N1. “We still don’t fully understand how the virus got into dairy herds in the first place or how it spread from farm to farm.”

No plans to recommend vaccinations

Despite the availability of effective vaccines, currently there are no plans to recommend vaccinations, Doron said.

“It is an active decision not to vaccinate farm workers or animals so far,” she said. Infections in farm workers have been very mild to this point, so vaccination is not justified.

“The risk to the general public from H5N1 is still very low,” added Doron, but those who work with dairy cattle should take caution.

Julio Figueroa, MD, FIDSA, Chief of Infectious Diseases at LSU Health New Orleans, said the death of the Louisiana resident was likely related to a backyard flock the man had that included wild birds.

He said that Louisiana is dealing with a very active flu season, with many cases of respiratory syncytial virus (RSV) as well. Hospitals are asking patients with flu symptoms if they have any exposure to birds. Figueroa noted that the state has many wild birds and many hunters of geese and ducks, so there are plenty of opportunities for potential exposure to H5N1.

Testing for H5N1 is available at public health labs and commercially, said Figueroa. The tests look for H3 and H1 flu viruses; if those are not detected, then further testing is done to determine whether the patient has H5N1.

Doron said drinking unpasteurized milk from dairy herds with H5N1 has killed cats, but there have not been any cases of humans being infected after drinking raw milk. Research must be conducted on raw milk and related food items like raw milk aged cheese.

Going forward, Doron said, interagency cooperation will be important because human health officials will need to interact with animal health officials. “There are lot of things that still need to happen that require interagency cooperation.”