Scientists are sounding the alarm about cases of H5N1 flu in cows in the US because it’s easier to jump to humans. Here in Europe, steps are being taken to prepare.
Bird flu, which spread to dairy cows and then farm workers in the United States this spring, could become a global health risk — but the extent of the threat is unknown, and those responsible in Europe and elsewhere could be caught unprepared if the situation worsens.
The cases in the United States are the latest wave of highly pathogenic avian influenza (H5N1), which has been circulating among migratory birds and mammals for several years, mainly in Europe and the Americas.
Since March, the strain has spread to 145 cattle in 12 US states and infected four dairy workers, all of whom have recovered.
There is no evidence of human-to-human spread, a key indicator of pandemic risk, while no human cases of the strain have been reported in Europe, according to the European Center for Disease Control and Prevention (ECDC). the public is at low risk of infection.
Still, experts say there are already enough warning signs for European countries to monitor the virus and prepare to respond quickly if the situation changes.
Waiting for the virus to emerge among populations on this side of the Atlantic would allow H5N1 to spread unchecked long enough that it would be difficult, if not impossible, to eradicate.
Transmission from cows to humans
Colin Russell, an evolutionary biologist at the center, told L’Observatoire de l’Europe Medical: “Everything can change very quickly and it’s difficult to establish a precise timetable because it depends on the form of the process of emergence” at the University of Amsterdam and Influenza and Other Respiratory Viruses. Chair of the European Scientific Working Group (ESWI).
“If we don’t know what we’re missing, we might have a problem,” Russell said.
The outbreak in the United States worries scientists because the H5N1 virus was first reported in cattle, making it more risky to spread to humans, and the H5N1 virus has been found to be deadly. the past
According to the World Health Organization (WHO), between 2003 and 2024, the H5N1 virus caused 889 illnesses and 463 deaths in 23 countries, representing a 52% case fatality rate.
Although the US strain does not yet have the mutations that allow it to spread rapidly between humans, researchers said this week that the tipping point may be closer than previously thought after they found signs of transmission between small animals in laboratory tests.
“This is a little worrying, because it means that the virus has the ability to spread from one mammal to another through the air,” pathologist at the Erasmus University Medical Center.
His research focuses on bird flu and other emerging viral diseases, but he was not involved in the latest study.
Taking measures against the H5N1 virus
Kuiken and other experts say the risk the H5N1 virus poses to populations around the world is moderately higher than before the U.S. cattle outbreak, but even a slightly higher risk is enough to cause concern.
“The most likely outcome is extinction rather than significant change and enough change to spread to other countries,” the group’s head, Munir Iqbal, told L’Observatoire de l’Europe Health about bird flu and Newcastle disease. Pirbright Institute.
But where H5N1 is already present, “the virus is invisible and therefore everything should be treated as something contagious.”
Some countries are taking steps to prepare for the H5N1 virus, although the US dairy cattle strain poses the latest threat in Europe.
Finland, for example, offers vaccinations to 10,000 workers at high risk of exposure to bird flu and monitors fur farms for possible cases throughout the summer.
Meanwhile, German and Italian researchers tested samples from cattle and goats in areas where the virus has been circulating among birds in recent years and found no evidence of infection.
Several other European countries, including the Netherlands, Spain, Norway, Sweden, France and Belgium, will soon begin their own studies, Kuiken said.
“When you suddenly realize that a species that you didn’t pay much attention to might be infected, you want to look back to see if that happened,” Kuiken said.
“Looking to the future, many laboratories now consider that they cannot rule out the possibility of such unusual epidemiological events occurring in Europe as well.”
The European Commission is also stockpiling 665,000 doses of pre-pandemic vaccines, which help protect against influenza strains with pandemic potential, and could purchase an additional 40 million doses if needed.
Epidemics elsewhere in the world
The International Vaccine Consortium for Epidemic Preparedness Innovations (CEPI) is bringing together a group of experts to support global access to H5N1 influenza vaccines should the situation worsen.
Dr Ruth Harvey, deputy director of the Global Influenza Center at the Francis Crick Institute, told L’Observatoire de l’Europe Health that control of the H5N1 virus in Europe is important for now.
“We can do a risk assessment and then respond accordingly,” Harvey said.
The American epidemic is not the only one on the radar of experts.
Cases of avian influenza caused by different strains have been reported in India, China, Australia, and Mexico, where the infected person did not come into contact with animals and died from the disease.
Beyond the dairy cow crisis, Russell said, all countries should screen animal pathogens for possible human contamination and establish a reporting infrastructure to quickly share that information with the international community.
“In this particular situation, there is an opportunity to make a call to arms to increase vigilance against these viruses on a global scale,” Russell said.