MONDAY, April 22, 2024 (HealthDay News) — The H5N1 avian flu virus that’s infecting U.S. cattle is increasingly showing up in mammals — a dangerous sign that it could someday easily infect people.

That’s the warning issued late last week by World Health Organization chief scientist Dr. Jeremy Farrar, CNN reported.

“We have to watch, more than watch, we have to make sure that if H5N1 did come across to humans with human-to-human transmission that we were in a position to immediately respond with access equitably to vaccines, therapeutics and diagnostics,” he said at a news conference held on WHO’s new definition for airborne pathogens.

In rare instances, H5N1 can infect a human who’s been in regular close contact with infected animals, as happened in a Texas cattleman earlier this month, but so far, human-to-human transmission is very difficult.

Increasingly, however, the virus is popping up in mammals that are much closer kin to humans than birds are.

“The great concern, of course, is that in doing so and infecting ducks and chickens — but now increasingly mammals — that that virus now evolves and develops the ability to infect humans,” Farrar said. “And then critically, the ability to go from human-to-human transmission.”

According to WHO, the death toll that could happen would be catastrophic: Since 2003, only 889 cases of human avian flu infection are known worldwide, but in 463 (52%) of those cases, the infected person died.

“This virus is a really scary virus. It’s something I would hate to see in humans,” Dr. Richard Webby, who directs the WHO’s coordinating center for studies on the ecology of influenza, told CNN.

Webby is also a scientist at St. Jude Children’s Research Hospital. He’s been studying H5N1 for two decades, and said the move to mammals is ominous.

“What’s happening now there are lots more small mammals being infected with this virus and we’ve ever seen in the past 20, close to 25 years of monitoring, so that is absolutely concerning,” he said.

Right now, H5N1 doesn’t seem to have picked up mutations that make human-to-human transmission a possibility, so “this virus has got quite a hurdle to overcome to become a real sort of human pathogen,” Webby said.

The virus involved in the one human case reported this month in Texas has been studied by the U.S. Centers for Disease Control and Prevention, which said it did seem vulnerable to existing antiviral medications.

The man involved in that case only displayed minor symptoms, but was placed in isolation. At the time, the CDC labeled the threat to the public as “low.”

The current outbreak of H5N1 among U.S. cattle herds has popped up in eight states — Texas, New Mexico, Kansas, South Dakota, Idaho, Michigan, Ohio and North Carolina.

The CDC said it has also created a candidate H5N1 vaccine virus. The strain would be in readiness to help produce a viable vaccine, should the need arise.

More information

The U.S. Centers for Disease Control and Prevention has more on bird flu.

SOURCE: CNN

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