Bird Flu in Human Has Mutation, but Risk Is Low: CDC

Chickens in Texas in a file photograph. Brandon Bell/Getty Images

The avian influenza that infected a person in Texas has a change from the influenza from animals, according to the U.S. Centers for Disease Control and Prevention (CDC).

Genomic sequencing from the patient showed “one change (PB2 E627K) that is known to be associated with viral adaptation to mammalian hosts,” the CDC stated in a summary of the testing results.

But that change has been recorded before in humans and animals, “with no evidence of onward spread among people,” the agency added.

Rajendram Rajnarayanan, an assistant dean of research at Arkansas State University, said on X, formerly known as Twitter, that the mutation alone “is not sufficient to enable efficient human to human transmission” but that detection of the change “highlights the value of increased genomic surveillance and rapid dissemination of sequence data.”

Officials said on April 1 that the person became ill after coming into contact with cows that likely have highly pathogenic avian influenza A(H5N1), also known as bird flu. The person experienced symptoms, primarily pink eye.

Cattle in multiple states have begun showing symptoms associated with the virus, including fatigue, and cases have been confirmed recently among the animals in Idaho, Kansas, Michigan, New Mexico, and Texas. The Ohio Department of Agriculture said on April 1 that a positive test came from a herd in the state, although it was awaiting confirmation from the U.S. Department of Agriculture.

The Ohio department “is working with state industry partners and federal agencies to encourage farmers and veterinarians to report cattle illnesses quickly, to monitor potential additional cases and minimize the impact and risk to farmers, farmworkers, consumers, and other animals,” the department said in a statement.

The dairy farm at which cows tested positive recently acquired cattle from Texas, officials said. Many of the other states involved have also reported that cattle recently came from Texas, and the bulk of the cases so far have been in Texas. That “suggests cow-to-cow transmission,” Caitlin Rivers, an infectious disease epidemiologist at the Johns Hopkins Center for Health Security, said on X.

The U.S. Department of Agriculture has said that the spread of the illness means “transmission between cattle cannot be ruled out.”

Wild birds are known to harbor the virus and transmit it to other birds and may have transmitted the illness to the cows, officials say. Federal and state officials say the food supply is safe because pasteurization would kill any influenza present in milk, and properly cooking eggs will eliminate any risk.

Overall, the CDC said its genomic sequencing didn’t change its assessment that the risk to humans is low.

Virologists at Cornell University who have sequenced samples of the highly pathogenic avian influenza, or HPAI, from animals said that the work is important as major questions remain.

“When there is spillover of HPAI to a new species, especially to mammals, it is always concerning, as the virus may adapt and gain the ability to transmit between animals,” Diego Diel, an associate professor of virology, said in an interview published by the school.

“We will study how HPAI spilled over into dairy cows to understand why this outbreak happened,” he added. “There are a number of very important questions about its source and the risk of transmission to other animals and humans that need to be addressed.”

Dr. Peter Marks, director of the Center for Biologics Evaluation and Research within the Food and Drug Administration, answers a question during a Senate Health, Education, Labor, and Pensions Committee hearing to discuss the ongoing federal response to COVID-19 at the U.S. Capitol in Washington on May 11, 2021. Greg Nash/AFP via Getty Images

Vaccines?

The CDC says that no vaccines to prevent the illness are currently available in the country and that regular influenza shots don’t provide any protection against any highly pathogenic avian influenza A viruses.

There are, however, vaccine candidates that are ready for manufacturing if that becomes necessary, the agency said. “Preliminary analysis indicates that they may provide reasonable protection against H5N1 influenza viruses,” it said in a statement.

Dr. Peter Marks, a top U.S. Food and Drug Administration official, said at a conference this week that the government has stockpiled vaccines against H5N1, including some shots that could be “reasonably good matches” for the avian influenza, EndPoints News reported.

Some avian influenza vaccines are authorized in other parts of the world. European authorities, for instance, have made a shot called Aflunov available.

“I think just because of being on edge from COVID, there are a lot of people looking at what’s going on here, and there’s probably a pretty low threshold to pull the trigger here,” Dr. Marks said.

Luciana Borio, the FDA’s former acting chief scientist, said that she wasn’t as confident as Dr. Marks was regarding whether the United States is prepared. She said the United States needs a “100-day mission” to deal with new threats such as this new virus.