Scientists are concerned about the bird flu outbreak in US cows

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These infections represent the first widespread outbreak of bird flu in cows.
Bird flu outbreak in mink sparks concern about spread in people In the past two weeks, health officials have detected H5N1 in cows from 16 herds across six states — a number that is likely to increase as US surveillance is stepped up.
Researchers have previously documented1 sporadic infections of cows with flu viruses closely related to H5N1, but no widespread outbreaks had been detected until now.
Avian flu freezes coastal bird research in South Africa Of particular interest is whether the virus is passing from infected cows to uninfected ones, because that would suggest the virus has become more adept at transmission in mammals.
But there aren’t enough viral sequences of animals infected later in the outbreak for genomic data to confirm cow-to-cow spread, he says.
Addressing these questions will offer insights into how widespread bird flu infections could be in cattle globally, she says.
The animal that no virologist wants to see a flu outbreak in, is the pig.
Specifically, the vaccine includes antibodies produced against a human H5N8 virus isolated in Russia and an avian H5N1 virus isolated in the United States.


In six US states, farms are home to a concerning strain of avian influenza that researchers are keeping a close eye on as it spreads to cattle and even one human.

This is the first large-scale bird flu outbreak among cows, according to these infections. Daniel Goldhill, an evolutionary virologist at the Royal Veterinary College in Hatfield, UK, says the outbreak is worrisome because humans routinely come into contact with cattle on farms, providing the virus with plenty of opportunities to spread to people.

Although they are closely monitoring the situation, health officials have stated that, as of right now, there is still little risk to the public. The constant fear, according to Goldhill, is that viruses will catch us off guard. “We’re not sure what their next move will be. “.

Researchers are working feverishly to determine how well antiviral medications and potential vaccines will combat the current strain of the virus, as well as to update diagnostic kits for prompt patient identification. Along with attempting to determine whether the cows’ infection came from birds or another source, they are also keeping an eye out for any changes in the circumstances that might put people at risk.

Icahn School of Medicine at Mount Sinai in New York City virologist Florian Krammer says, “There are a lot of questions and, so far, not a lot of answers.”.

Where was the virus originally discovered, and what is the current situation?

Chinese birds were the first to be found infected with the H5N1 influenza strain in 1996. Hundreds of millions of domestic and wild birds have died as a result of its violent spread since 2021. According to Kanta Subbarao, director of the World Health Organization’s (WHO) Collaborating Centre for Reference and Research on Influenza in Melbourne, Australia, it has also sporadically infected mammals, such as seals and bears, which have turned into “accidental hosts” of the virus, which is primarily avian.

An outbreak of bird flu in mink raises concerns about human transmission.

Six states and sixteen herds of cows have tested positive for H5N1 in the last two weeks, and as US surveillance efforts intensify, this number is expected to rise. Though no widespread outbreaks have been found up to this point, researchers have previously documented1 occasional infections of cows with flu viruses closely related to H5N1.

According to Goldhill, a virus’s chances of evolving a strain that is harmful to humans increase with the number of mammalian species it infects. According to the US Centers for Disease Control and Prevention (CDC), one dairy worker in Texas has contracted the infection, but the worker is on the mend. The CDC reports that the worker’s only complaint was inflammation of the eyes, and that low viral levels in their nose indicate they do not have a respiratory infection.

With one significant exception—the worker’s variant of the virus has a mutation linked to more effective spread in mammals—it is closely related to the strains of the virus found in Texas dairy cattle. According to Goldhill, the mutation’s existence in the human sample was expected as it has been observed on numerous occasions, such as in H5N1-infected foxes2 and cats 3.

Why is it important to know whether the virus is spreading amongst cows?

How the cattle are becoming infected is a crucial question for researchers. Reducing the number of farms and individuals infected with H5N1 will depend on the outcome. Richard Webby, a virologist at St. Louis, says, “This is a manageable situation—we just need to understand how this virus is getting around.”. Memphis, TN’s Jude Children’s Research Hospital.

Research on coastal birds in South Africa is frozen by avian flu.

Whether the virus is spreading from infected to uninfected cows is especially interesting, as it would indicate the virus has improved its ability to spread among mammals. Epidemiological data show that cow-to-cow transmission is occurring in light of the virus’s detection at multiple farms across the US, and that wild birds are not always responsible for the virus’s spread within the farms, according to Webby. However, he notes that there are insufficient viral sequences from animals that became infected later in the outbreak for genomic data to support cow-to-cow transmission.

It will be crucial to determine the exact method of virus transmission if cows are affected, according to Webby. According to a Science report, the evidence currently available indicates that the virus levels are highest in the milk of the animals. According to Webby, this implies that the H5N1 virus may not be disseminating among cows via the air, a route of transmission that would be challenging to manage and might permit highly rapid spread. The virus would spread more slowly if cows were contracting it through contact with contaminated objects, like milking machines, as opposed to through the air.

In spite of the virus’s recent global spread, infections in cattle have only recently become apparent, and only in the United States. Collecting data to address these issues may help explain why. A virologist at Erasmus University Medical Center in Rotterdam, the Netherlands named Marion Koopmans questions if the virus has evolved new defenses against the environment or if there is something special about the way cattle are raised in the area. According to her, answering these concerns will shed light on the potential global prevalence of bird flu infections in cattle. According to Krammer, it will be critical for health officials working outside of the US to begin searching for proof of unreported outbreaks.

What might make scientists more worried?

Scientists are closely monitoring H5N1 samples worldwide for mutations known to indicate that the virus is getting better at spreading in mammals, even though it is unlikely that bird flu will spread widely among humans. Its inability to easily infiltrate the cells lining the mouth and nose has contributed to the virus’s limited human distribution. However, according to Goldhill, it would be problematic if the virus underwent mutations that made it easier for it to enter these cells.

Krammer says he would particularly search for modifications to the region of the viral genome that codes for a polymerase, a class of enzyme. The term “a hotspot for adaptation to mammals” refers to a region of this enzyme. Additionally, according to Webby, researchers are searching for mutations that would lessen the strain’s susceptibility to antiviral medications.

Pigs are the animal that no virologist wants to see experiencing a flu outbreak. According to Krammer, pigs are a “mixing vessel” where strains of mammalian and avian viruses can combine to increase their ability to spread to humans because they are hosts to numerous influenza A viruses.

How well will the current medications and vaccines work against this strain, according to our knowledge?

A list of potential vaccines that offer protection against H5N1 and are potentially mass-produced is kept up to date by the WHO. In addition, some nations—the US included—keep a small supply of vaccine doses on hand in case they need to vaccinate vulnerable groups like front-line employees.

A potential vaccine targets two strains that are closely related to the viral strain that was isolated from the infected individual, according to the CDC. As the outbreak continues, Webby says his team will test new samples because laboratory studies have shown that the WHO vaccines can guard against viral samples taken from cows early in the outbreak. In particular, the vaccine contains antibodies made against an H5N1 virus isolated in the United States and an H5N8 virus isolated in humans that were both isolated in Russia. As per Webby, they are able to identify the cow virus “very, very well.”.

Since people lack pre-existing immunity to H5N1 and closely related viruses, it would be helpful to learn more about the level of immunity that these candidate vaccines produce against the circulating strain, adds Subbarao.

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