Public health officials and scientists have been on high alert since the second-ever human infection of a “highly pathogenic” strain of bird flu from the cattle industry in Texas in this spring, prompting rapid coordination efforts between multiple government agencies to contain the outbreak.
“Don’t panic. Do be careful,” avian influenza specialist at Johns Hopkins Medicine Kawswar Talaat told the Washington Examiner as her primary piece of advice to the general public. “It is absolutely something that scientists are watching very carefully.”
The Centers for Disease Control and Prevention reported the second-ever U.S. human case of H5N1 bird flu in a Texas dairy worker on April 1, marking the first case of cow-to-human transmission of the disease.
Although the risk of infection to the general public remains very low, the Biden administration in May announced a joint effort between the Department of Agriculture and the Department of Health and Human Services to contain the spread to the tune of $101 million.
First cases of H5N1 in cows
The first-ever human case of H5N1 in the United States occurred in Colorado in 2022 at a poultry processing facility, but cases in cows have been a growing concern over the past several weeks.
Talaat said that, up until now, H5N1 had been largely limited to bird populations and animals that have regular contact with birds.
“The fact that it is in cows is really unusual. We haven’t seen that before,” she said.
Reports of H5N1 in cows began circulating in late March. As of May, the disease has been reported in cattle herds in nine states, including Texas, Idaho, Michigan, and Ohio. A total of 42 herds of cattle are known to be infected.
Talaat noted that H5N1 has been present in bird populations since 1995, but human-to-human transmission has not been recorded.
“The fact that it is now spreading among mammals is a little bit concerning,” Talaat said. “It’s one step closer from birds to people, but again, still not a concern that [it] spreads effectively from person to person.”
How bird flu affects humans
According to the World Health Organization, there have been 888 cases of H5N1 infection in 23 countries worldwide since 2003.
Most human infections with the virus are linked to close contact with living or dead infected birds or contaminated environments, and most of the cases are clustered in Southeast Asia, China, and Egypt.
Symptoms of avian influenza viruses in humans are similar to traditional flu-like symptoms, often starting as a mild respiratory infection. More severe illness can progress if left untreated, leading to gastrointestinal and neurological problems.
Of the total number of cases, 463 deaths were reported to WHO.
The CDC reports that neither the 2022 Colorado patient nor the current patient in Texas have experienced severe symptoms and responded to treatment quickly.
Concern of human-to-human spread
The WHO’s chief scientist, Jeremy Fararr, told reporters in April that human spillover is an “enormous concern,” especially since the virus appears to have mutated to spread more quickly between mammals.
Although denuded H5N1 particles have been found in approximately 20% of tested commercial milk samples, the samples were tested using PCR rapid testing, which only requires a small fragment of virus DNA to produce a positive test.
Public health experts largely agree that the pasteurization process likely prevents the particles from being infectious to humans, but more thorough testing is warranted to determine the exact size of the DNA fragments found.
The Food and Drug Administration announced in May that the agency will be spending an additional $8 million for testing and monitoring of the commercial milk supply.
Public health officials mount response
When asked if public concern over the H5N1 outbreak was overblown considering the lack of human-to-human transmission, Talaat said she was encouraged by the rapid government and industry response despite the relatively low risk of widespread human infections.
“We often wait until it is a little too late to respond,” Talaat said, noting a “sense of panic and urgency” is usually the motivating factor for action.
In mid-April, the scientific community at large began increasing the pressure on the USDA to release more information on the genetic sequences of the H5N1 virus samples.
Andrew Pekosz, professor of microbiology and immunology at Johns Hopkins Bloomberg School of Public Health, told the Washington Examiner that genetic sequencing data without other information, including the dates and locations of samples, is very difficult to use effectively. “It’s really hard to get a good sense of what the extent of the outbreak is,” he said.
HHS will be coordinating preparation efforts through the CDC that include $34 million for developing rapid testing and antiviral drugs that can be disseminated on a global scale. The CDC will also be contributing $8 million for vaccine development.
Concern the strongest for livestock and agriculture workers
The CDC recommended this week that workers in dairy and poultry farms with infected livestock wear personal protective equipment, or PPE, to mitigate human exposure and transmission of H5N1.
The Texas health department began offering gloves, masks, goggles, and gowns to dairy farm workers in April, but only a handful of farms have accepted them. Idaho and Wisconsin have had similar results in encouraging farmers to accept the free PPE.
Part of the hesitancy is that PPE is not designed for working in hot conditions, such as in milking parlors. Goggles are likely to fog up, for example, and N95 respirator masks are ineffective when wet.
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For the general public at this point, however, Talaat said the risk of contracting avian flu should not be a top priority.
“If you’re not handling birds, and you’re not handling animals that interact with birds, it’s really not yet a concern,” Talaat said.
