Experts are warning about a new type of 'bird flu' found in Nevada dairy cows: 'You are strictly advised to avoid drinking raw milk'

The discovery that dairy herds in Nevada have been infected with a strain of the H5N1 bird flu not before observed in cows has placed virologists and researchers on high alert. Among other reasons, the Nevada Department of Agriculture's announcement shows that eradicating the virus from the cattle herd in the United States would be far more difficult than federal authorities had predicted—or even hoped for.

Dairy herds in Nevada have been infected with a strain of H5N1 bird flu not before observed in cows, putting virologists on high alert.

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On Friday, there was a second, perhaps more catastrophic blow: According to a technical brief issued by the United States Department of Agriculture, the D1.1 genotype features a genetic alteration that may allow the virus to replicate more easily in animals, including humans.

The D1.1 genotype has been found in wild birds across all North American flyways, as well as animals and poultry, so it's not unexpected that it's spread to cows. However, many virologists believe that its discovery in Nevada dairy cows marks a watershed moment in the spread of H5N1, and it might portend greater danger for humans in the future.

"Given the fact that D1.1 appears to be more virulent in humans, this could indicate a major change in terms of public health risks from the previous scenario with the B3.13 strain," veterinary science pioneer Juergen Richt, Director of the National Institutes of Health Center on Emerging and Zoonotic Infectious Diseases, told Fortune.

In answer to an emailed series of questions, a spokesperson for the government Centers for Disease Control and Prevention (CDC) stated that the agency continues to believe the risk to human health for the general population is minimal. "However, people with close, prolonged, or unprotected exposures to infected birds or other animals (including livestock), or to environments contaminated by infected birds or other animals, are at greater risk of infection," the spokesperson said.

The USDA stated on Friday that, while the Nevada cattle did not show clinical indications of infection prior to testing, such signs have subsequently been observed, as well as the deaths of a significant number of wild birds around the afflicted farms.

Should humans take extra precautions? What is the extent of the risk? And are there any mitigation measures that should already be in place on America's farms and dairies?

The urgency of those concerns implies that in the coming weeks, a high priority should be put on the prompt sharing of information and testing updates from government sources on which researchers and health authorities frequently rely. However, the flow of information cannot be taken for granted anymore.

On Jan. 21, the Trump administration ordered the U.S. Department of Health and Human Services (HHS) to halt practically all external communications, including papers and health guidelines, until a Trump-appointed official could be installed and review them. Such a step is not unique, but when the information freeze expired on February 1 without being completely released, Democratic leaders began to scream foul.

One significant casualty of that move was the CDC's Morbidity and Mortality Weekly Report. The MMWR, as it is called, is an important source of information about public health issues. The MMWR did not publish for the first time in almost sixty years on January 23rd and again on January 30th. Publication resumed on February 6th, but there was no mention of bird flu or any information regarding the three H5N1 studies that were supposed to be released in January, according to the Washington Post.

Furthermore, the Wall Street Journal reports that the Trump administration intends to lay off thousands of US Department of Health and Human Services (HHS) personnel. Senior public-health officials are allegedly being instructed to rate personnel depending on how important their roles are.

Depending on where such cuts fall throughout the department's many agencies, activities such as tracing avian flu outbreaks and licensing new treatments may be impacted. And Robert F. Kennedy Jr., Trump's candidate to lead HHS in 2023, has indicated he will thank government health experts for their public service. We want to take a sabbatical from studying infectious illnesses for around eight years."

These developments have heightened scientists' and researchers' concerns about the spread of H5N1, which, according to the CDC, has now infected 959 dairy herds in the United States and killed 156 million poultry, driving egg prices to record highs due to scarcity.

Researchers are also debating whether dairy workers should be inoculated using current bird flu vaccine supplies from the government stockpile, as well as if frontline workers should be required to wear personal protective equipment on dairy farms and egg laying facilities.

This all boils down to the timely flow of information and communication, which experts warn is being stifled at a vital time.

"This is chilling but not surprising, given the gag put on scientists and the manipulation of scientific communication in 2020 at the start of the COVID pandemic," says Bright, a vaccine researcher who filed a whistleblower complaint against the Trump administration in 2020 and has been urging health officials for months to increase bird flu testing and precautions.

"When it happened in 2020," Bright says, "it slowed the response, sowed distrust in science and public health, and resulted in many more deaths." It's appalling that lessons were not learned, and we're in the same or worse situation--not just with H5N1, but with several continuing epidemics in the United States."

A Nevada official told Fortune that the new instances of D1.1 in cows have been connected to dairy farms in Churchill County, where six herds have been quarantined. Previously, J.J. Goicoechea, the state's agriculture director, told Reuters: "We obviously aren't doing everything we can and should, or the virus wouldn't be getting in." Goicoechea said Nevada farmers must implement "good animal health safety practices and bolster biosecurity measures" for their animals.

Where does this leave humanity? According to Angela Rasmussen, a virologist at the University of Saskatchewan, the Nevada development "increases the risk of zoonotic human cases—that is, from cows to farmworkers." Beyond that, experts are concerned about D1.1's capacity to mutate (perhaps in ways not seen in B3.13). This flexibility may make the virus more easily transmitted from person to person.

"This new genotype of H5N1 virus, D1.1 was associated with more severe illness and death in the few known human infections," Bright explained. "It (the Nevada case) is a significant event, because we now know how easily H5N1 viruses can spread among dairy cows, from farm to farm, jump from milk to other mammals, including mice and cats, and even infect people."

According to James Lawler, director of the University of Nebraska's Global Center for Health Security, federal health authorities have made "some positive steps" in recent months to enhance testing through the National Milk Testing Strategy, as well as to test and subtype influenza in humans.

"To better control risk, however, we should aggressively ramp up testing and isolation of affected dairy herds and animals, facilitate more widespread surveillance and testing in people, and accelerate vaccine development and production," Lawler says. Clinicians must also be aware that the virus is spreading, Bright says, and should "test for influenza, not guess."

Scott Hensley, a virus immunologist at the University of Pennsylvania, concurred. "We need to closely monitor D1.1 viruses because they have already shown the ability to adapt and cause severe disease in humans," according to Hensley. "Our H5N1 vaccine stocks are well matched to the D1.1 viruses and would likely give significant levels of protection—we need to crank up H5N1 vaccine manufacturing in case these viruses mutate and transfer from human to human."

Meanwhile, Richt warns, people should avoid drinking raw milk, which may contain live virus from infected dairy cows, wash their hands often, and report influenza-like symptoms, presumably so that testing may be conducted. States may follow California's lead, where the governor declared a bird flu emergency and health officials helped distribute millions of pieces of personal protective equipment to farmworkers.

Every effort to restrict the virus, however, will ultimately rely heavily on the dissemination of accurate and timely information—and a government and health community committed to combating bird flu and its worrying subtypes.

"There is a lot that we do not know about D1.1. viruses, and we will all be working overtime to learn more in the coming days and weeks," Hensley says. The most important aspect of the struggle will be the widespread dissemination of professional knowledge.