Based on the information available to date, the World health Organization (WHO) considers the overall public health risk posed by the A(H5N1) virus to be “low”. At the same time, the risk of infection is considered “low to moderate” for people exposed to infected birds or animals or contaminated environments.
As the virus is carried around the world by migratory birds, there is certainly a risk of infection of cows in other countries, detailed the WHO.
Investigations underway to determine severity of H5N1 bird flu
As the virus is carried particularly by migratory birds, “there is certainly a risk that cows in other countries will be infected,” said Wenqing Zhang, head of the WHO’s global influenza programme. For now, she believes that the original infection came from birds, but in the United States they are still trying to determine whether or not there was cow-to-cow transmission.
Investigations are underway to determine the extent and severity of the H5N1 avian flu detected in around thirty flocks in eight American states since March.
“Although much is still being investigated, this suggests that the virus may have found… transmission routes other than those we know so far,” Wenqing Zhang said during a press conference in Geneva.
Although this may seem worrying, “it is also a testimony to the effectiveness of disease surveillance which allows us to detect the virus”.
Closely monitor and evaluate the spread and evolution of the virus
“As WHO and partners closely monitor, review, assess and update the risk associated with H5N1 and other avian influenza viruses, we call on countries to remain vigilant, promptly report human infections, where appropriate, to quickly share sequences and other data, and to strengthen biosecurity measures on farms,” said the WHO official.
For the WHO, it is therefore important to emphasize that the avian flu virus is evolving, as is the risk associated with the virus. “So it’s very important to monitor it closely.” To do this, it is a matter of “closely monitoring and evaluating the spread and evolution of the virus, and updating responses”.
An outbreak of avian flu has spread for several weeks in dairy cow herds in the United States, the only one affected for the moment. Media reports indicate that a person working on an affected dairy farm was infected but had only mild symptoms.
Pasteurized milk sold in stores is “safe”
The WHO reports that the H5N1 avian influenza virus of the particular clade (2.3.4.4b) currently infecting cows in the United States first appeared in 2020 (the first H5N1 virus appeared in 1996).
Based on available studies conducted in the United States, virus fragments found in pasteurized milk are not infectious, WHO said, noting that ongoing sampling suggests that raw milk from infected cows may contain live viruses, which can pose a threat, especially to agricultural workers.
“The fact that this has been detected, that we are informed of an individual case somewhere on a farm, this demonstrates that surveillance is working,” rejoiced Christian Lindmeier, WHO spokesperson. . He confirmed the conclusions of American authorities, who believe that milk sold in stores is “safe” and that pasteurization kills the virus present in milk.
Avoid contact with animals on farms and live animal markets
In this fight, as agricultural workers are professionally exposed to these zoonotic viruses, the WHO is prioritizing their protection.
“As for the general public, as I said, the risk is currently considered low,” insisted Ms. Zhang.
The consumption of raw or incompletely cooked meat, eggs or milk is not recommended.
Regarding the consumption of pasteurized milk, it should be safe to consume at this stage.
Additionally, residents and travelers to areas where outbreaks of avian influenza have been found in animals should avoid contact with animals on farms and live animal markets.
They must refrain from entering areas where animals are likely to be slaughtered, but also from any contact with surfaces apparently contaminated by animal excrement.
Consumption of raw or incompletely cooked meat, eggs or milk is also not recommended.
Almost daily updates from the United States
More generally, the WHO recommends that States strengthen disease surveillance in animals and humans and quickly share information and data on genetic sequences.
“Surveillance works,” argued Dr. Wenqing Zhang, adding that WHO receives information and updates “almost daily” from the American centers with which the Organization collaborates.
Ms. Wang stressed that serological studies are underway “but may take time.” These data taken from genetic sequencing “are available, some having been made available very early”, she detailed, noting that “the genetic sequencing data from the human case were immediately made available”.
