The US health agency CDC announced on Mondaythat a patient had tested positive for the H5N1 bird flu virus and was being treated with antiviral medication. The only symptom is red eyes and the patient is on the road to recovery. He was ordered to isolate himself.
This case is nevertheless remarkable: it is only the second time that a person in the USA has been proven to be infected with bird flu. The first case occurred in 2022, after direct contact with infected poultry. This time it appears that the patient was infected from dairy cows infected with the virus. However, this is not yet certain.
The CDC emphasized that the case does not change the risk assessment for the general public. The risk of infection remains low. Only people with close or long-term unprotected contact with infected animals would be at higher risk.
Avian flu has been spreading among birds to a previously unknown extent for just over two years; Not only are the numbers of infected animals unusually high, but also those in affected countries in Europe and North America.
In addition to birds, mammals are also increasingly affected; the list of affected species ranges from otters to red foxes and dairy cows.
The latter have recently become more common in the USA. Several cases were discovered last week in the states of Texas, Kansas and New Mexico. An epidemiologist from the University of Texas described this development as worrying. The trade magazine Science He said it could be that this strain of bird flu is spreading directly and has mutated in a way that could allow it to better infect humans as well.
In general, bird flu viruses are not well adapted to humans. A person must inhale very large amounts of viruses to become infected. This usually only happens through very intensive contact with sick birds, for example on poultry farms. Since the virus affects the bronchi in humans, person-to-person transmission via the upper respiratory tract is almost non-existent
According to the World Health Organization (WHO), around 900 people have been infected with bird flu so far, and a good half of them have died from the virus.
H5N1 was first identified in China in 1996. A year later, the first human infection was documented.