SEATTLE — How likely is it, for humans to catch bird flu?
Though human-to-human transmission is rare, it is possible, according to a virology expert. What infectious diseases doctors are watching closely is whether other farm animals are getting infected with the avian flu strain, known as H5N1.
There are now at least 55 confirmed human cases of the bird flu in the U.S., according to the latest data from the Centers of Disease Control and Prevention, posted on Nov. 22.
The CDC also confirmed the first U.S. bird flu case in a child, in California. Health officials are investigating.
Eleven of the 50-plus U.S. bird flu cases were confirmed in Washington state. Those who caught it in Washington were in close contact with infected poultry, according to the state health department website.
While 11 isn't a terribly high number, a local virology expert said it's worth watching the spread of bird flu and whether humans are able to infect other humans with it.
"We have not seen that, but absolutely it's possible," said Dr. Alex Greninger, a professor of laboratory medicine and pathology at UW Medicine and assistant director of the UW Medicine Clinical Virology Laboratory.
Greninger said there has so far been no known case of human-to-human transmission of the bird flu, adding that it is rare. Of greater concern, is when the bird flu manages to infect other farm animals, like pigs.
In late October, the U.S. Department of Agriculture confirmed a pig was found infected with the H5N1 bird flu strain that's been circulating among wild birds and poultry in the Pacific Northwest and beyond.
Greninger said this matters, big time.
"That's something that concerns people who study influenza, because pigs have both receptors in their respiratory tracts, that for avians and for humans, and so they're classically thought to be sort of the intermediate host between birds, pigs, humans," Greninger told HealthLink.
He described pigs as "mixing vessels" for viral mutations, thereby increasing the chance for a bird flu strain to adapt and infect humans.
Greninger points out, farm workers should take extra precautions.
"We're monitoring for those sort of mutations, and we're trying to make sure that if individuals are going to get infected. One, that they wear protective equipment on these farms, so there are fewer cases in humans," Greninger said.
Symptoms of bird flu among people have ranged from non-existent, to mild or severe.
Some cases have observed redness in the eye and other flu-like symptoms like fever and cough.
Research has shown bird flu is good at infecting cell receptors in the eye, hence the emphasis for farm workers to use personal protective equipment.
For the latest information on bird flu cases in Washington, visit the Department of Health's website.