2024-09-26 12:10:24
The danger of human-to-human transmission of bird flu is growing. Researchers are warning of a new global epidemic.
Cases of bird flu (H5N1) have been reported in 14 US states, affecting over 200 dairy herds. The virus has so far been detected in 15 people in the US. What is of particular concern to experts is that three people apparently did not become infected directly from cows, but were in contact with an infected person.
One of them was hospitalized in Missouri in August, and two health care workers also developed symptoms after contact with her. The fear is that the virus could also be transmitted from person to person.
- Virologist Christian Drosten had also warned of a new pandemic.
Virus triggered global pandemics
Scientists at the British Pirbright Institute also share these concerns. Their approach: Since the virus is already being transmitted from mammal to mammal in some species (such as marine mammals, fur-bearing animals or even cattle), they are raising the question of whether humans are next. And they have come to alarming conclusions: According to their findings, the global containment measures are not sufficient to prevent a possible new pandemic. Worse still: they are not working.
Virologist Thomas Peacock explains: “Influenza A viruses (as in bird flu, Editor’s note) have caused more documented global pandemics in human history than any other pathogen. Historically, pigs have been considered optimal intermediate hosts, helping avian influenza viruses adapt to mammals before jumping to humans.” Now, however, new evolutionary paths have opened up.
His main criticism is that H5N1 is notifiable in the USA for poultry, but not for mammals. The US Department of Agriculture only requires tests for lactating livestock before transport between states, says Peacock. For wild animals, only carcasses are tested. This means there is a possibility that virus variants could spread unnoticed.
It literally states: “What is giving scientists sleepless nights is the possibility that chains of transmission are spreading and developing unnoticed in farm workers’ barracks, pig farms or developing countries because of tight testing criteria, fear of government authorities or scarce resources.”
Vaccines available for humans
Scientists fear that the virus could develop under the radar. They are calling for more control and monitoring, as well as the use of vaccinations. Flu vaccines have been approved for poultry, which reduce the burden of disease but do not prevent infection and have varying success rates.
For humans, there are stocks of H5 vaccines that produce similar antibodies against H5N1. They could be produced on a large scale using mRNA platforms if the virus jumps to humans.
The situation is causing concern among experts around the world. The main risk lies not only in the virus’s enormous ability to mutate, but also in the fact that H5N1 viruses “have increasingly passed from animals to humans in the past,” explains influenza researcher Gülsah Gabriel from the Leibniz Institute of Virology in Hamburg. They have led to a “very high lethality” – i.e. mortality – there.
According to the World Health Organization (WHO), up to 50 percent of those who have become infected on bird farms or at wildlife markets in Asia in recent years have died. According to the Robert Koch Institute, no one in Germany has yet been infected with a bird flu virus.
The British researchers emphasize: “The severity of a future H5N1 pandemic is still unclear. Recent H5N1 infections in humans have a much lower mortality rate than previous H5N1 outbreaks in Asia, in which half of the reported infected people died. The lower severity in the US cases may be due to infection via the eye rather than viral pneumonia.”