Concerns about human infection with bird flu: ‘Risk of epidemic’

A recent case of human infection with avian flu has raised concerns among virologists. In Ecuador, a 9-year-old girl was admitted to the intensive care unit of a hospital in Quito this week. She was seriously ill due to an infection with the virus variant H5N1, which is very pathogenic among birds.

People have already become infected with this variant, but never before has anyone become so ill. “So far, a handful of cases have been reported of people who have been diagnosed with the virus, but they had no or only mild symptoms,” says virologist Thijs Kuiken.

He finds it worrying that this girl has become so ill. “We do not yet know whether the girl has underlying conditions and has therefore ended up in intensive care,” continues Kuiken. “It is clear that the virus can enter the lungs.” That entails risks, according to the virologist. “Once a virus enters the human body, virus mutations become more likely to become dominant that make the virus more easily transmissible from person to person.”

Virologist Wim van der Poel therefore calls the girl’s serious illness a wake-up call. “What we need to be alert to is that there is no human-to-human transmission,” he says. “If that does happen, you will get a rapid spread of the virus and you run the risk of an epidemic.”

The variant of the virus that infected the Ecuadorian girl, H5N1, is a variant that spreads via wild migratory birds. That is why the virus has already been detected in birds on almost all continents. “Only in Australia and Antarctica are no known cases of birds infected with this variant,” says Kuiken.

The virus reaches poultry farms via wild birds, and thus to people. The chance that the virus will mutate in such an infection into a variant that is contagious among humans is still small, emphasizes virologist Marion Koopmans in NPO Radio 1 program News and Co.

“The current bird flu infections that we see in humans are hardly contagious between humans,” she says. “But that’s not a fixed characteristic, that can change. And we don’t want to see that change.”

Van der Poel therefore finds it reassuring that there are no indications yet that this specific virus variant can be transmitted from person to person. “But we have to keep an eye on its spread and try to get it better under control.”

That control is still a challenge, especially because the virus is also circulating among wild birds. “All kinds of measures are possible in poultry farming, such as shielding poultry from wild birds,” says Van der Poel. A vaccine for poultry is also currently being researched. “That can provide better protection against bird flu and reduce its spread.”

However, vaccinating wild birds is not possible. “That makes it difficult to get the virus completely under control,” the virologist continues. “In practice, the virus infections that are now circulating among wild birds should decrease through natural development.”