Bird flu is considered one of the viruses that could cause the next pandemic. What is currently known?
Infection with bird flu is usually fatal for poultry. Austria has now classified the entire country as a risk area. Poultry farmers are particularly affected.
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But the virus can also be dangerous to humans. It is considered a candidate pathogen that could trigger the next pandemic. The worrying thing is that the highly infectious virus is spreading in more and more ways. Migratory birds have spread it worldwide and not only introduced it into poultry houses. Minks, penguins, foxes, cats and tigers, among others, have already been infected.
In the USA, the virus spread to cattle, and the virus was recently also detected in pigs. A so-called spillover – the jump to other species – is not uncommon.
But what is particularly threatening is that the virus is getting closer and closer to people. Because people have already become infected. However, direct person-to-person transmission is still relatively rare.
What is the status?
In the USA, it was confirmed for the first time in March that the H5N1 pathogen of clade (variant) 2.3.4.4b was detected in dairy cows. At the end of March, the first farm worker tested positive for the virus. As CNN reported, citing Texas researchers, the dairy worker sought medical attention after experiencing painful red, swollen, weeping eyes with burst blood vessels. However, he did not have a fever and his lungs were clear, according to the study published by the scientists.
According to the latest information, 46 people in the USA have been infected since the outbreak. Almost all of them had direct contact with dairy cattle or poultry. Direct person-to-person transmission has not been proven, but there are suspected cases.
So far, the illnesses following an infection in humans have been mild to moderate, explained the US health authority CDC. The usual flu symptoms appear such as fever, sore throat, shortness of breath and cough. Conjunctivitis, nose or gum bleeding, diarrhea, vomiting and abdominal pain are also reported. Neurological symptoms (seizures) and encephalitis may also be associated with bird flu infection. However, such cases have not yet been reported in the current outbreak.
The American health authority has so far classified the risk to the general public as low. Bird flu is currently primarily a problem for animal health.
It literally says: “Transmission of the avian influenza virus from an infected person to a close contact has only occurred rarely in other countries in the past. And when it did happen, it was limited and not sustained and did not extend beyond close contacts.”
The virus has been circulating in American dairy farms since at least November 2023, so it was not discovered for months. The U.S. Department of Agriculture officially confirmed the presence of the H5N1 virus in dairy cows in Texas on March 25.
The US Department of Agriculture ordered, among other things, that only dairy cows with a negative bird flu test could be transported from one US state to another. Experts see this as insufficient.
“This is a drop in the ocean,” Mike Worobey from the University of Arizona told Science magazine. This limitation is comparable to that of air traffic during Covid times, “long after the viruses have established themselves in a particular location.” It could simply be too late.
Can H5N1 cause a new pandemic?
The WHO spoke out in mid-April. Your lead scientist Dr. Jeremy Farrar expressed concern that the bird flu virus has an “extremely high” mortality rate among those infected around the world. It is crucially important whether transmission can take place from person to person.
Evolutionary biologist Michael Worobey also warns: “We are in uncharted territory here, as an H5N1 virus adapted to mammals is spreading for the first time in land mammals with which hundreds of thousands of people come into contact every day,” he says, referring to the situation in the USA. The next pandemic virus will come from a situation very similar to this one.
Jerome Adams also sees a similar situation to that at the beginning of the corona pandemic. He headed the public health service in the USA until 2021. He told Business Insider: “If it continues to spread in animals, at some point it will cause problems for humans, either because we don’t have food, because they have to start wiping out herds, or because there is a big one in humans jump.” And he warns: “The more it replicates, the greater the chance it has of mutating.”
