Bird flu is spreading among cattle; scientists want more data on H5N1

WAs the H5N1 bird flu spreads to more herds of dairy cows, scientists and pandemic experts in this country and abroad are calling on the U.S. government to release more information to help them assess the risk the outbreaks pose to livestock operations and people .

Three and a half weeks after first announcing the surprising news that cows from a Texas dairy herd had tested positive for H5N1, government agencies involved in the investigations have yet to reveal what research shows about whether pasteurization of milk specific virus kills. And until Thursday, U.S. officials had not disclosed whether the now 29 affected herds in eight states represent a single, linked outbreak fueled by the movement of livestock from the Texas Panhandle, where the first outbreak was discovered. At this time, STAT was advised that this does not appear to be the case.

Other countries are trying to determine whether this event is a strange one-off, or evidence that the crafty virus has evolved to more easily infect livestock, and what risk their own herds – and possibly humans – might face if the latter would be the case. WHERE. But they operate largely in the dark because the United States has released such scant information, said Marion Koopmans, head of the viroscience department at the Erasmus Medical Center in the Dutch city of Rotterdam.

“A country with capacity like the United States should be able to generate this information within a few days,” Koopmans said. “I would expect very quick, very transparent updates and it’s somewhat surprising not to see that happening.”

Koopmans said it is crucial to find out whether this situation is somehow unique to the United States or is changing risk assessment for ruminants – cattle, sheep and related species – worldwide. “You would expect that there would be some responsibility to share,” she told STAT.

The U.S. Department of Agriculture, which is leading the investigation into the outbreaks, has pushed back on the criticism.

“USDA has been committed from the very beginning to the timely and transparent release of information related to the outbreak as it becomes available,” a spokesperson said by email. “We will continue to work to provide timely and accurate updates to the public, our stakeholders and the scientific community as we learn more.”

Experts believe the USDA should continually collect samples to check for dangerous changes in the virus, but only a few genetic sequences from this outbreak have been uploaded to GISAID, the international database widely used by scientists. And the genetic sequences shared are from the beginning of the outbreak, meaning outside scientists can’t check whether the virus has changed as it moved from cow to cow or herd to herd.

In its response to STAT, the USDA said it has offered to provide outside scientists with copies of an example virus For research purposes. Other viruses from the outbreaks are currently being analyzed by the USDA and the Centers for Disease Control and Prevention and the sequences will be shared in the coming days, the spokesperson said.

In a document with frequently asked questions On its website, the USDA has stated that “analysis of sets of viruses found in livestock to date has found no changes in the virus that would make it more transmissible to humans and between humans.” However, the agency believes the virus has been passed from cow to cow, possibly through sequential use of milking equipment.

Michael Osterholm, director of the University of Minnesota’s Center for Infectious Disease Research and Policy, said the USDA’s limited data sharing is creating a sense of distrust about how the outbreak investigation is being handled.

“They create the perception that something is happening or not happening that would not meet with the public’s approval,” Osterholm said. “And this is really a shame. There is no evidence here that there is some kind of smoking gun, that someone has done something wrong. Just tell us what you do. And that doesn’t happen.”

Rick Bright, former head of the Rockefeller Foundation’s short-lived Pandemic Prevention Institute and now a consultant on pandemic preparedness, noted that when the first detected outbreak of H7N9 bird flu exploded in China in the spring of 2013, country condemned for not sharing more information and more genetic sequences. (Although H7N9 appears to have waned, more than 1,200 human cases of H7N9 have been reported between 2013 and 2017, 37% of which were fatal.)

Bright criticized the US for being less forthcoming, noting that international negotiations on pandemic preparedness are currently trying to reach an agreement that could be signed at the World Health Assembly meeting in May. “In the context of these pandemic agreement talks right now, where they’re trying to come to an agreement on data sharing and the benefits of data, etc., and the United States of America is in the middle of an outbreak in dairy cattle…not willing to share data in a timely and transparent manner, what does that say to the rest of the world?”

The criticism comes in a week that saw the Biden administration announce a new program to help 50 countries, mainly in Africa and Asia, develop better disease surveillance and preparedness to ward off future pandemics, and a congressional committee tasked with to try to determine whether the Covid-19 pandemic was caused by a virus spillover from nature or a laboratory accident that concerned the editor of the journal Science.

In the case of the H5N1 outbreaks in dairy cattle, there were reports seen by veterinarians as early as February evidence that something is wrong in some herds in the Texas Panhandle. But it wasn’t until March 25 that the USDA confirmed that a dairy herd in Texas had been infected with H5N1, a virus that until then had not been seen as a threat to cows. In H5’s nearly thirty-year history of infecting poultry, wild birds, carnivorous mammals and the occasional human, cows have not been part of the saga. Until now.

In the days that followed, several additional outbreaks were confirmed, in Texas, then Kansas and Michigan, and then New Mexico, Idaho, Ohio, North Carolina and South Dakota. (USDA maintains a list here.The USDA told STAT Thursday that it can establish links between affected herds in Texas, New Mexico and Kansas, but there is currently no evidence to suggest that all affected herds in all affected states have received cows from Texas.

Although H5N1 kills many of the species it infects, it does not appear to make livestock seriously ill. Feed consumption decreases and the milk from infected cows becomes discolored and syrupy. USDA has reported that milk contains high levels of the H5N1 virus.

Farmers have been told to throw away milk from infected cows, even though the USDA, the Food and Drug Administration and the CDC all routinely say they believe pasteurization would kill the viruses. But that is based on research done with other pathogens, not with H5N1.

STAT has been pressing the USDA over whether research is being done to test the effect of pasteurization on H5N1-contaminated milk. USDA officials deferred questions to the FDA, saying it is responsible for food safety. The FDA said the work wasn’t done yet. When asked if the investigation was ongoing and when the results would be available, the FDA did not respond.

“I’m shocked that we still don’t have the data on pasteurization,” Bright said. “The public deserves to know what experiments are being done [and] when can we expect data from this.”

The spread of H5N1 bird flu to cows is a concern for a major industry, but also raises the concerns of scientists monitoring this virus. There is always the concern that if the virus acquires the changes necessary to spread easily among a mammalian species, it could more easily make the jump to humans.

Moreover, if the virus found its way from cows to pigs, alarm bells would really ring. Pigs are often referred to as ‘mixing vessels’ for influenza viruses because they can be infected by both avian influenza viruses and human influenza viruses. If both types of viruses infect a pig at the same time, the pathogens can exchange genes and potentially produce a version of H5N1 that is better adapted to transmission between and between humans.

The USDA has already suggested that viruses from one of Michigan’s infected dairy herds have caused an outbreak at a nearby poultry farm. “Additionally, we have similar evidence that the virus has also spread from dairy farms back to nearby poultry farms via an unknown route,” the latest FAQ document states. The USDA is currently investigating how this could have happened, including whether human movement between farms could have played a role.

The locations of the affected dairy farms have not been disclosed, so it is unclear whether they are near pig farms. But the very possibility of spread from cows to other animals has raised questions about how farmers on affected farms dispose of contaminated milk. The USDA told STAT farmers to consult their state’s agricultural authorities for advice on safely disposing of milk.

Scientists studying H5N1 would like to gain a better understanding of why herds of dairy cows in multiple states have become infected in such a short time. And they suspect that USDA investigations have yielded more information than has been released about how much of the spread is due to livestock movements, or whether contaminated feed supplies or the spring migration of infected wild birds play a role.

That question is crucial; Efforts to stop the spread to cows and between herds depend on how they become infected, Osterholm said. “It gets to the heart of, ‘How do I pull the pump handle here?’” he said, referring to the famous story of British doctor John Snow removing the handle from a pump in central London, which he rightly believed which was the source of cholera infections in 1854. After Snow removed the pump handle, the infections stopped.

If the outbreaks are all traced to a farm or farms in Texas, “that says there’s some unique transmission happening here between production animal and production animal that we don’t understand,” he said. But if viruses from wild birds caused outbreaks in multiple places, it would be important to focus on the challenging task of minimizing that risk.

Osterholm said the Covid pandemic should have taught government officials that transparency and clear communication are key to successful outbreak management.

“For me that is missed here. And I can’t possibly understand why,” he said. “This is a serious public health challenge, but it should not be a media challenge. And they make it one.”

This article was updated Thursday with a new outbreak total – 29 – issued by the USDA.