US authority warns:

Bird flu more widespread than assumed

A duck farm in the US state of New York

(Bild: APA/AP)

At the beginning of the year, a person infected with the H5N1 bird flu virus died for the first time in the USA. The CDC still considers the risk to the general population to be low. However, according to a recent analysis, the virus is more widespread than previously assumed - even among humans!

In the course of blood tests on vets in 46 US states and Canada, it was found that H5N1 had spread unnoticed among humans. However, human-to-human transmission has not yet been proven. Of the 150 veterinarians participating in the investigation, 25 stated that they had come into contact with infected or possibly infected dairy cows.

Avian flu antibodies found in veterinarians
Of particular concern was the fact that three vets were found to have avian flu antibodies, although they emphasized that they had neither felt any symptoms nor had any contact with infected cows. One of them stated that he had been in contact with infected poultry.

In addition, the affected test subjects came from states where no previous bird flu outbreaks had been recorded. "We don't know the extent of this outbreak in the US," Seema Lakdawala, a virologist at Emory University, had to concede in an interview with the New York Times.

Colored electron micrograph showing particles of avian influenza A H5N1 virus (yellow) in epithelial cells (blue)

(Bild: AP/CDC/NIAID)

Recent outbreak in poultry and dairy farms
Avian influenza is currently widespread in wild birds around the world, and many wild mammals are also infected. The virus has recently led to outbreaks in poultry and dairy farms in the USA. It is still unclear how the vets became infected with the pathogen. According to studies, H5N1 is transmitted via the raw milk of affected cows - i.e. primarily via milking machines and equipment.

New variant discovered in cows
According to media reports, a new H5N1 variant was recently discovered in dairy cows. Virologists worldwide are alarmed because the new mutation is reported to have a greater ability to replicate in mammals. A senior scientist at the Johns Hopkins Center for Health Security stressed to the news channel CNN that it is essential to monitor farms more closely "so that we can better detect outbreaks and protect people".