Scientists worry the U.S. is missing bird flu cases among farm workers: shots

The U.S. Department of Agriculture is recommending that milk-producing cows be infected with highly pathogenic avian influenza (HPAI H5N1) before being transferred to another state after the virus was detected in samples of pasteurized milk taken by the food department. Dairy producers are ordered to carry out inspections. and drug management.

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The U.S. Department of Agriculture is recommending that milk-producing cows be infected with highly pathogenic avian influenza (HPAI H5N1) before being transferred to another state after the virus was detected in samples of pasteurized milk taken by the food department. Dairy producers are ordered to carry out inspections. and drug management.

Justin Sullivan/Getty Images

During the current U.S. outbreak, there is only one officially recorded case of avian influenza being transmitted from cattle to humans.

But epidemiologist Gregory Gray said he believes the true number may be much higher, based on what he's heard from veterinarians, ranchers and workers themselves when the virus hit herds in the state. Be suspicious of.

“We know that at a time when H5N1 was devastating dairy farms, some workers sought treatment for flu-like illnesses and conjunctivitis,” he said. grayan infectious disease epidemiologist at the University of Texas Medical Branch in Galveston.

”“There's no way to measure it, but it seems biologically very likely that they also have the virus,” he says.

Gray is I spent decades studying Respiratory infections in people who handle animals such as dairy cows. He noted that there have been “clusters of influenza-like illnesses and conjunctivitis.” documented and previous trend Involved Avian influenza strains like this one are deadly to poultry.

Fortunately, the virus' genetic sequence does not indicate that it has evolved to spread easily among humans.

Still, epidemiologists say it's important to track potential infections. They are concerned that the infection could be passing undetected to some people, especially if the infection is mild and temporary. Texas dairy worker infected with virus.

“Given the number of cases in cattle that have been recorded, I think some level of human exposure is probably occurring,” he says. Dr. Andrew Bowman, Associate Professor of Veterinary Preventive Medicine at The Ohio State University. “We really don't know.”

Limited testing raises concerns

Thirty-six herds were affected in nine states. Federal health officials said in a briefing Wednesday that local and state health officials have tested about 25 people for the virus and are monitoring more than 100 people for symptoms.

It states that these people are “in the footprints of where the cows were detected.” Dr.Demetre Daskalakiswho is affiliated with the Centers for Disease Control and Prevention, declined to provide details about the actual location.

“The threshold for an individual to get tested is very low,” he added.

The lack of testing early in the outbreak is not necessarily surprising. In places like Texas and Kansas, veterinarians weren't thinking about bird flu when it first appeared in early March, and it took some time to identify a virus as the cause.

However, the total number of tests performed on humans to date appears to be small. jessica leibleran environmental epidemiologist at Boston University School of Public Health.

“If you're trying to determine where human transmission from these facilities is occurring, you want to test as many workers as possible,” Leibler said. studied the risks New zoonotic influenza and livestock issues.

Gray also said the virus is probably far more geographically widespread in cattle than the reported cases indicate, and that it “probably has the potential to spread to far more people than we know.” “There is,” he points out.

The federal government has been quick to assess the safety of the dairy supply. On Wednesday, the Food and Drug Administration announced findings showing no infectious virus was present in nearly 200 samples taken from dairy products across the country.Initial results on ground meat It's also safe.

But “serious gaps” remain in public health authorities' ability to detect avian influenza among cattle workers, a task made even more difficult by the fact that some cases do not show symptoms. says Leibler. “The opportunities for workers to be exposed to this virus are very widespread.”

Only complicating matters — the true scale of the outbreak in cattle remains unclear despite new developments Federal exam requirements Because moving cattle interstate may help understand the situation.

“Some dairy herds have animals that appear clinically normal but are latently infected; [that] It’s very difficult to know where to conduct surveillance,” Bowman said.

Call for aggressive measures to trace potential human infections

Health systems are likely to cope with an alarming increase in human cases of avian influenza. According to modeling Conducted by CDC.

Federal health officials are monitoring influenza activity in emergency departments and hospitals. The hundreds of clinical laboratories that perform the tests are tasked with reporting their findings. And in early April, a CDC health alert was sent to clinicians advising them to be on the lookout for people who worked with livestock and had flu-like symptoms or conjunctivitis.

However, these precautions may not be enough to prevent the spread of infection.

“I'm concerned that if we waited until we saw a surge in these systems, we would probably already have more widespread community transmission,” he said. Dr. Mary Margaret Phil, Deputy State Epidemiologist for the Tennessee Department of Health. Instead, she says aggressive testing should be used.

Fillnote has an anecdote about a farm worker who was tending to cattle in some areas where the virus is widespread and contracted a mild illness, adding, “To understand what's going on… “There is not enough visibility into whether testing is being done in these populations.”

Leibler said not only workers but also their families and community members need to be tested to stay ahead of the virus in case it evolves to spread easily among humans. It states that there is.

Dr. Rodney Young Doctors in Texas are wary of an outbreak of influenza, especially among people who are around livestock, but say there are no signs of anything unusual so far.

“All of a sudden we're doing more testing, and I've never seen anyone fit that description,” said Young, regional director of the division of family and community medicine at the Texas Tech University Health Science Center School of Medicine in Amarillo. ” he says..

Get buy-in from dairy farms

Gray said these rural workers are more likely to get sick for a number of reasons, including remoteness, reluctance to receive medical care, lack of health insurance, concerns about immigration status, and farmers' reluctance. states that it can be difficult to discover and measure. Wave the flag to let people know that an infectious disease exists.

He said the farms he works with consider protecting workers and curbing the spread of this virus to be a “top priority,” but at this point they are running all the risks of going public. he says.

Dr. Fred Gingrich This is a major barrier to close cooperation between federal health officials and industry during the current crisis, he said.

Dairy farmers currently do not receive compensation for reporting infections in their herds, said Gingrich, executive director of the American College of Bovine Practitioners. This is different from poultry farmers receiving compensation for losses associated with culling birds if they discover an infected person.

“So what's their motive for reporting?'' He said, “It's the same virus, it's just not killing cows.”

Mr Gray has successfully begun collecting samples from humans and cows at several dairy farms that have recently dealt with the virus. This is part of a study he launched before the H5N1 outbreak in response to concerns about SARS-CoV-2 spillover to farms.

They will be looking for evidence of exposure to new strains of influenza, including avian influenza, but he has a background in the field and has assured that the farm's anonymity will be maintained in the published paper. You can accomplish that.

His biggest concern is the possibility of outbreaks occurring on other types of farms.

“We know when the virus hits the poultry farm because the birds die, but the pigs may or may not develop severe symptoms,” he says. It's much bigger.”