avian influenza

after-mice-drink-raw-h5n1-milk,-bird-flu-virus-riddles-their-organs

After mice drink raw H5N1 milk, bird flu virus riddles their organs

avian influenza, bird flu, CDC, cows, dairy cows, fda, flu, H5N1, Infectious disease, Mice, milk, outbreak, raw milk, Science, USDA, virus / /

Deadly dairy —

No, really, drinking raw milk during the H5N1 outbreak is a bad idea.

–

Fresh raw milk being poured into a container on a dairy farm on July 29, 2023, in De Lutte, Netherlands.

Enlarge / Fresh raw milk being poured into a container on a dairy farm on July 29, 2023, in De Lutte, Netherlands.

Despite the delusions of the raw milk crowd, drinking unpasteurized milk brimming with infectious avian H5N1 influenza virus is a very bad idea, according to freshly squeezed data published Friday in the New England Journal of Medicine.

Researchers at the University of Wisconsin-Madison squirted raw H5N1-containing milk from infected cows into the throats of anesthetized laboratory mice, finding that the virus caused systemic infections after the mice were observed swallowing the dose. The illnesses began quickly, with symptoms of lethargy and ruffled fur starting on day 1. On day 4, the animals were euthanized to prevent extended suffering. Subsequent analysis found that the mice had high levels of H5N1 bird flu virus in their respiratory tracts, as well their hearts, kidneys, spleens, livers, mammary glands, and brains.

“Collectively, our data indicate that HPAI [Highly Pathogenic Avian Influenza] A(H5N1) virus in untreated milk can infect susceptible animals that consume it,” the researchers concluded. The researchers also found that raw milk containing H5N1 can remain infectious for weeks when stored at refrigerator temperatures.

Bird flu has not historically been considered a foodborne pathogen, but prior to the unexpected outbreak of H5N1 in US dairy cows discovered in March, it had never been found at high levels in a food product like milk before. While experts have stepped up warnings against drinking raw milk amid the outbreak, the mouse experiment offers some of the first data on the risks of H5N1 from drinking unpasteurized dairy.

Before the mouse data, numerous reports have noted carnivores falling ill with H5N1 after eating infected wild birds. And a study from March in the journal Emerging Infectious Diseases reported that over half of the 24 or so cats on an H5N1-infected dairy farm in Texas died after drinking raw milk from the sick cows. Before their deaths, the cats displayed distressing neurological symptoms, and studies found the virus had invaded their lungs, brains, hearts, and eyes.

While the data cannot definitely determine if humans who drink H5N1-contaminated raw milk will suffer the same fate as the mice and cats, it highlights the very real risk. Still, raw milk enthusiasts have disregarded the concerns. PBS NewsHour reported last week that since March 25, when the H5N1 outbreak in US dairy cows was announced, weekly sales of raw cow’s milk have ticked up 21 percent, to as much as 65 percent compared with the same periods a year ago, according to data shared by market research firm NielsenIQ. Moreover, the founder of California-based Raw Milk Institute, Mark McAfee, told the Los Angeles Times this month that his customers baselessly believe drinking H5N1 will give them immunity to the deadly pathogen.

In normal times, the Centers for Disease Control and Prevention and the Food and Drug Administration strongly discourage drinking raw milk. Without pasteurization, it can easily be contaminated with a wide variety of pathogens, including Campylobacter, Cryptosporidium, E. coli, Listeria, Brucella, and Salmonella.

Fortunately, for the bulk of Americans who heed germ theory, pasteurization appears completely effective at deactivating the virus in milk, according to thorough testing by the FDA. Pasteurized milk is considered safe during the outbreak. The US Department of Agriculture, meanwhile, reports finding no H5N1 in retail beef so far and, in laboratory experiments, beef patties purposefully inoculated with H5N1 had no viable virus in them after the patties were cooked to 145°F (medium) or 160°F (well done).

To date, the USDA has reported that H5N1 has infected at least 58 dairy herds in nine states.

After mice drink raw H5N1 milk, bird flu virus riddles their organs Read More »

raw-milk-fans-plan-to-drink-up-as-experts-warn-of-high-levels-of-h5n1-virus

Raw-milk fans plan to drink up as experts warn of high levels of H5N1 virus

avian influenza, bird flu, CDC, cows, fda, H5N1, health, mammary glands, milk, raw milk, Science / /

facepalm —

Raw milk fans called warnings “fear mongering,” despite 52% fatality rate in humans.

–

A glass of fresh raw milk in the hand of a farmer.

Enlarge / A glass of fresh raw milk in the hand of a farmer.

To drink raw milk at any time is to flirt with dangerous germs. But, amid an unprecedented outbreak of H5N1 bird flu in US dairy cows, the risks have ratcheted up considerably. Health experts have stepped up warnings against drinking raw milk during the outbreak, the scope of which is still unknown.

Yet, raw milk enthusiasts are undaunted by the heightened risk. The California-based Raw Milk Institute called the warnings “clearly fearmongering.” The institute’s founder, Mark McAfee, told the Los Angeles Times this weekend that his customers are, in fact, specifically requesting raw milk from H5N1-infected cows. According to McAfee, his customers believe, without evidence, that directly drinking high levels of the avian influenza virus will give them immunity to the deadly pathogen.

Expert Michael Payne told the LA Times that the idea amounts to “playing Russian roulette with your health.” Payne, a researcher and dairy outreach coordinator at the Western Institute for Food Safety and Security at UC Davis, added, “Deliberately trying to infect yourself with a known pathogen flies in the face of all medical knowledge and common sense.”

Much remains unknown about the biology of avian influenza in cattle. Until March 25, when the US Department of Agriculture confirmed the virus in a dairy herd in Texas, cattle were generally considered virtually resistant to H5N1. But since then, the USDA has tallied 42 herds in nine states that have contracted the virus. Epidemiological data so far suggests that there has been cow-to-cow transmission following a single spillover event and that the 42 outbreak herds are connected by the movement of cattle between farms.

The limited data on the cows so far suggests that the animals largely develop mild illness from the infection and recover in a few weeks. Their mammary glands are the primary target of the virus. A preprint published earlier this month found that cows’ udders are rife with the molecular receptors that bird flu viruses latch onto to spark an infection. Moreover, the glands contain multiple types receptors, including ones targeted by human flu viruses as well as those targeted by bird flu viruses. Thus, dairy cows could potentially act as a mixing vessel for the different types of flu viruses to reassemble into new, outbreak-sparking variants.

With the virus apparently having a field day in cows’ udders, researchers have found raw milk to be brimming with high levels of H5N1 viral particles—and those particles appear readily capable of spilling over to other mammals. In a case study last month, researchers reported that a group of about two dozen farm cats developed severe illness after drinking milk from H5N1-infected cows. Some developed severe neurological symptoms. More than half the cats died in a matter of days.

Deadly virus

Data on flu receptors in the two animals may explain the difference between cows and cats. While the cow’s mammary gland had loads of multiple types of flu receptors, those receptors were less common in other parts of the cow, including the respiratory tract and brain. This may explain why they tend to have a mild infection. Cats, on the other hand, appear to have receptors more widely distributed, with infected cats showing viral invasion of the lungs, hearts, eyes, and brains.

Raw milk devotees—who claim without evidence that drinking raw milk provides health benefits over drinking pasteurized milk—dismiss the risk of exposure to H5N1. They confidently argue—also without evidence—that the human digestive system will destroy the virus. And they highlight that there is no documented evidence of a human ever becoming infected with H5N1 from drinking tainted milk.

The latter point on the lack of evidence of milkborne H5N1 transmission is true. However, the current outbreak is the first known spillover of highly pathogenic avian influenza (HPAI) to dairy cow mammary glands. As such, it presents the first known opportunity for such milk-based transmission to occur.

Before pasteurization became routine for commercial milk production, raw milk was a common source of infections, serving up a cornucopia of germs. According to the FDA, in 1938, milkborne outbreaks accounted for 25 percent of all foodborne disease outbreaks. In more recent times, milk has been linked to less than 1 percent of such outbreaks. The Centers for Disease Control and Prevention notes that areas where raw milk was sold legally between 1998 and 2018 had 3.2 times more outbreaks than areas where the sale of raw milk was illegal.

In a Q&A document, the Food and Drug Administration notes that it does “not know at this time if HPAI A (H5N1) viruses can be transmitted through consumption of unpasteurized (raw) milk and products (such as cheese) made from raw milk from infected cows.” However, the agency goes on, because of that lack of data and the potential for infection, the FDA recommends halting all sales of raw milk and raw milk products from H5N1 infected or exposed cattle. In general, the agency recommends against consuming raw milk.

Globally, as of March 28, there have been 888 cases of H5N1 reported in humans in 23 countries. Of those 888 cases, 463 were fatal. That represents a 52 percent fatality rate; however, it’s possible that there are asymptomatic or undiagnosed cases that could alter that rate. In the US, only one human so far is known to have been infected with H5N1 in connection with the dairy cow outbreak—a farm worker who developed pink eye. The man had no respiratory symptoms and recovered. He did not consent to further follow-up, and researchers did not get consent to test the man’s household contacts to see if they, too, were infected.

Raw-milk fans plan to drink up as experts warn of high levels of H5N1 virus Read More »

fragments-of-bird-flu-virus-genome-found-in-pasteurized-milk,-fda-says

Fragments of bird flu virus genome found in pasteurized milk, FDA says

avian influenza, bird flu, CDC, cows, dairy cows, fda, flu, H5N1, Infectious disease, influenza, milk, pasteurization, Science, Uncategorized / /

Milk testing —

The test cannot tell if the virus is live. The FDA still assess milk supply as safe.

–

Cows being milked

Enlarge / Cows being milked

The Food and Drug Administration on Tuesday announced that genetic fragments from the highly-pathogenic avian influenza virus H5N1 have been detected in the pasteurized, commercial milk supply. However, the testing completed so far—using quantitative polymerase chain reaction (qPCR)—only detects the presence of viral genetic material and cannot tell whether the genetic material is from live and infectious viral particles or merely remnants of dead ones killed by the pasteurization process.

Testing is now ongoing to see if viable, infectious H5N1 can be identified in milk samples.

So far, the FDA still believes that the milk supply is safe. “To date, we have seen nothing that would change our assessment that the commercial milk supply is safe,” the agency said in a lengthy explanation of the finding and ongoing testing.

H5N1 made its startling jump to US dairy cows recently, with the first ever documented cases in a Texas herd confirmed on March 25. It has spread widely since then with at least 32 herds in eight states now known to be infected. The unexpected spread to bovines has raised fears that the virus is evolving to infect mammals more efficiently, and so poses a heightened risk of spread to and among humans.

But amid the alarming outbreak among the country’s dairy herds, federal agencies have appeared confident that the virus poses little risk to no risk to the safety of the milk supply.

“At this time, there continues to be no concern that this circumstance poses a risk to consumer health, or that it affects the safety of the interstate commercial milk supply because products are pasteurized before entering the market” the FDA wrote in an FAQ published Friday. “Pasteurization has continually proven to inactivate bacteria and viruses, like influenza, in milk.”

In the announcement Tuesday, the FDA also highlighted that multiple studies have shown that the pasteurization process for eggs, which uses lower temperatures than what is used for milk, is effective at inactivating H5N1.

Nevertheless, the FDA, along with the Centers for Disease Control and Prevention and the US Department of Agriculture, have continued to investigate potential risks, including establishing whether pasteurization can inactivate this specific virus. The FDA noted in its announcement Tuesday that, while pasteurization is expected to kill the virus, pasteurization is “different than complete sterilization.”

As such, it carried out the qPCR tests, expecting it might find some genetic fragments in the pasteurized milk because virus has been detected in raw milk. “Based on available information, pasteurization is likely to inactivate the virus, however the process is not expected to remove the presence of viral particles,” the FDA explained. “Therefore, some of the samples collected have indicated the presence of HPAI [Highly Pathogenic Avian Influenza] using quantitative polymerase chain reaction (qPCR) testing.”

The FDA did not indicate how many samples it has tested, where the samples were collected from, or the level of viral genetic material the samples contained.

The agency is now working on assessing whether it can identify if any virus particles are infectious using egg inoculation tests, which are considered a gold-standard for determining viral viability. It added that it will release results from those tests and others in “the next few days to weeks.”

“[W]e take this current situation and the safety of the milk supply very seriously. We recognize the importance of releasing further, actionable information,” the FDA said.

Meanwhile, the agency reported that the CDC’s food safety group has been closely monitoring emergency department data and flu testing data for any unusual trends in flu-like illness, flu, or conjunctivitis, which could indicate spread of H5N1 to people. “To date, surveillance systems do not show any unusual trends or activity,” the FDA said.

Fragments of bird flu virus genome found in pasteurized milk, FDA says Read More »

concern-grows-as-bird-flu-spreads-further-in-us-cows:-32-herds-in-8-states

Concern grows as bird flu spreads further in US cows: 32 herds in 8 states

avian influenza, bird flu, CDC, cows, dairy cows, fda, H5N1, herds, infection, milk, outbreak, Science, USDA, virus / /

Rapidly evolving —

Experts say the US is not sharing as much data on the outbreak as it should.

–

Greylag geese sit on a field and rest while a cow passes by in the background.

Enlarge / Greylag geese sit on a field and rest while a cow passes by in the background.

Researchers around the world are growing more uneasy with the spread of highly pathogenic avian influenza (H5N1) in US dairy cows as the virus continues to make its way into new herds and states. Several experts say the US is not sharing enough information from the federal investigation into the unexpected and growing outbreak, including genetic information from isolated viruses.

To date, the US Department of Agriculture has tallied 32 affected herds in eight states: Idaho, Kansas, Michigan, New Mexico, North Carolina, Ohio, South Dakota, and Texas. In some cases, the movement of cattle between herds can explain the spread of the virus. But the USDA has not publicly clarified if all the herds are linked in a single outbreak chain or if there is evidence that the virus has spilled over to cows multiple times. Early infections in Texas were linked to dead wild birds (pigeons, blackbirds, and grackles) found on dairy farms. But the USDA reportedly indicated to Stat News that the infections do not appear to be all linked to the Texas cases.

Spread of the virus via cattle movements indicates that there is cow-to-cow transmission occurring, the USDA said. But it’s unclear how the virus is spreading between cows. Given that even the most symptomatic cows show few respiratory symptoms, the USDA speculates that the most likely way it is spreading is via contaminated milking equipment.

Adding to the uncertainty of the virus’s spread, The New York Times on Friday reported that the one herd found infected with H5N1 in North Carolina showed no symptoms of the virus. This raises the possibility that the virus could be silently spreading in unknown numbers of other asymptomatic herds and states. In its most recent FAQ document, the USDA encouraged testing for H5N1 if herds show clinical symptoms, such as lethargy, fever, low milk production, and loose stools. But the Times noted that the agency has begun reimbursing farms for testing asymptomatic cows.

Meanwhile, the USDA also reported that it has evidence that H5N1 from dairy farms has spread back into birds in nearby poultry farms, but how this is happening is also unknown.

Data gaps

All the uncertainty and widespread transmission raises concern about how the virus is evolving to infect mammals and whether it is heading for humans. Last week, the chief scientist for the World Health Organization, Jeremy Farrar, told reporters in Geneva that the spread of the virus in US dairy cows is an “enormous concern,” according to CNN.  “The great concern, of course, is that in doing so and infecting ducks and chickens—but now increasingly mammals—that that virus now evolves and develops the ability to infect humans. And then critically, the ability to go from human-to-human transmission.”

In particular, experts are wary that the dairy cow outbreaks could spill over to nearby pig farms as it’s doing with nearby poultry farms. Pigs can be infected with both bird flu viruses and human flu viruses, making them potential melting pots for new recombinant flu strains.

So far, the USDA says that genetic sequences of H5N1 viruses infecting cows has not revealed any mutations that “would make it more transmissible to humans and between people.” But last Thursday, Stat reported that international experts have faulted the USDA for not sharing more genetic data from its investigation, among other information. Until this weekend, the agency had only shared a few genetic sequences in an international database of viral genome sequences (GISAID).

“A country with capacity like the United States should be able to generate this information within days,” Marion Koopmans, head of the department of viroscience at Erasmus Medical Center in the Dutch city of Rotterdam told Stat last week. “I would expect very fast, very transparent updates, and it’s somewhat amazing not to see that happening.”

On Sunday, facing mounting criticism, the USDA announced the release of 239 genetic sequences to GISAID. It noted it is also adding raw data to a US federal database “in the interest of public transparency and ensuring the scientific community has access to this information as quickly as possible.” The agency said it will continue to make such data available on a rolling basis.

Dr. Rosemary Sifford, the USDA’s chief veterinarian, told the Times, “Please recall that we’ve been engaged in this for less than a month. We are working very hard to generate more information,” she said.

Overall, the USDA and the US Centers for Disease Control and Prevention continue to consider the risk to the public to be low. Farmworkers and others who have direct contact with infected animals are encouraged to take precautions, however.

While deadly to birds, H5N1 in cows is relatively mild, rarely if ever causing deaths. Milk from sick animals contains high levels of virus, but it is being destroyed. Even if some infected milk makes its way into the milk supply, the Food and Drug Administration is confident that the virus would be killed in the pasteurization process. “Pasteurization has continually proven to inactivate bacteria and viruses, like influenza, in milk,” the agency said in an FAQ Friday. Some experts have called for data confirming this, though.

Concern grows as bird flu spreads further in US cows: 32 herds in 8 states Read More »

cows-in-texas-and-kansas-test-positive-for-highly-pathogenic-bird-flu

Cows in Texas and Kansas test positive for highly pathogenic bird flu

avian influenza, bird flu, cows, dairy cows, H5N1, health, kansas, milk, Science, texas, USDA / /

viral spread —

The risk to the public is low, and the milk supply is safe.

–

Image of cows

Wild migratory birds likely spread a deadly strain of bird flu to dairy cows in Texas and Kansas, state and federal officials announced this week.

It is believed to be the first time the virus, a highly pathogenic avian influenza (HPAI), has been found in cows in the US. Last week, officials in Minnesota confirmed finding an HPAI case in a young goat, marking the first time the virus has been found in a domestic ruminant in the US.

According to the Associated Press, officials with the Texas Animal Health Commission confirmed the flu virus is the Type A H5N1 strain, which has been ravaging bird populations around the globe for several years. The explosive, ongoing spread of the virus has led to many spillover events into mammals, making epidemiologists anxious that the virus could adapt to spread widely in humans.

For now, the risk to the public is low. According to a release from the US Department of Agriculture (USDA), genetic testing by the National Veterinary Services Laboratories indicated that H5N1 strain that spread to the cows doesn’t appear to contain any mutations that would make it more transmissible to humans. Though the flu strain was found in some milk samples from the infected cows, the USDA emphasized that all the milk from affected animals is being diverted and destroyed. Dairy farms are required to send only milk from healthy animals to be processed for human consumption. Still, even if some flu-contaminated milk was processed for human consumption, the standard pasteurization process inactivates viruses, including influenza, as well as bacteria.

So far, officials believe the virus is primarily affecting older cows. The virus was detected in milk from sick cows on two farms in Kansas and one in Texas, as well as in a throat swab from a cow on a second Texas farm. The USDA noted that farmers have found dead birds on their properties, indicating exposure to infected birds. Sick cows have also been reported in New Mexico. Symptoms of the bird flu in cows appear to include decreased milk production and low appetite.

But so far, the USDA believes the spread of H5N1 will not significantly affect milk production or the herds. Milk loss has been limited; only about 10 percent of affected herds have shown signs of the infection, and there has been “little to no associated mortality.” The USDA suggested it will remain vigilant, calling the infections a “rapidly evolving situation.”

While federal and state officials continue to track the virus, Texas officials aim to assure consumers. “There is no threat to the public and there will be no supply shortages,” Texas Agriculture Commissioner Sid Miller said in a statement. “No contaminated milk is known to have entered the food chain; it has all been dumped. In the rare event that some affected milk enters the food chain, the pasteurization process will kill the virus.”

Cows in Texas and Kansas test positive for highly pathogenic bird flu Read More »