The current bird flu outbreak began in 2020 and has already led to the deaths of tens of millions of poultry animals. The virus also affects wild birds and has now also been found in mammals on land and in the sea. Last month, to the surprise of experts, cows and goats were added to the list of affected species.

There is currently no evidence that H5N1 is spreading among humans. According to the WHO, there were at least several hundred cases in which people became infected from infected animals. In these cases, the death rate is “extraordinarily high,” said WHO expert Farrar.

From 2003 to April 1, 2024, the WHO said it registered a total of 889 human infections in 23 countries, 463 of which were fatal. That corresponds to a death rate of 52 percent.

The news that a person in the US state of Texas was infected with bird flu from dairy cattle also caused concern this month. Previously, livestock herds in Texas, Kansas and other US states had apparently become infected with H5N1 from wild birds. According to the WHO, the case in Texas is apparently the first time a human has been infected with H5N1 in a mammal.

If a virus can also affect mammals, it would come “closer to people,” emphasized Farrar. H5N1 is looking for “new, novel hosts”. Farrar called for closer monitoring of the infection process. It is important to know how many people have already been infected, “because that is where the adaptation (of the virus) will happen.”

The WHO expert warned that national and regional health authorities must have the capacity to detect the virus. This should enable humanity to “react immediately” if H5N1 is transmitted from person to person. Everyone must also have access to the vaccines and medications against the bird flu virus, the development of which has already begun.