April 23, 2024


WHO warns H5N1 bird flu detected in milk, survival in milk unknown


The World Health Organisation (WHO) said that the H5N1 bird flu virus strain has been discovered in very high concentrations in raw milk from infected animals, raising concerns about its transmission via dairy products, although the duration of survival in milk remains uncertain, AFP reported.


Avian influenza A (H5N1) initially emerged in 1996, but since 2020, there has been a significant rise in outbreaks among birds, accompanied by an increase in infections among mammals.


The H5N1 strain has resulted in the deaths of millions of poultry, with wild birds, and both land and marine mammals also falling victim to the virus.


Last month, cattle and goats were added to the list of infected animals, surprising experts as they were not previously believed to be susceptible to this strain of influenza.


Earlier this month, US authorities reported that a person working on a dairy farm in Texas was recovering from bird flu after being exposed to infected cattle.


Wenqing Zhang, head of the WHO's global influenza programme, said the case in Texas marks the first instance of a human contracting avian influenza from a cow.


Zhang said transmission from birds to cattle, between cattle, and from cattle to birds has also been observed during these recent outbreaks, indicating that the virus may have identified alternative routes of transmission previously unknown.


This incident in Texas represents only the second confirmed case of bird flu in a human in the United States and follows outbreaks that affected herds exposed to wild birds.


Zhang said there are multiple instances of affected cow herds in an increasing number of US states, indicating further transmission of the virus to mammals, and the virus has also been detected in milk from infected animals.


While Zhang confirmed the existence of a "very high virus concentration in raw milk," experts are still investigating the duration of the virus's survival in milk.


The Texas health department assured that infections in cattle do not pose a threat to the commercial milk supply, as dairies are mandated to discard milk from sick cows, and pasteurisation effectively eliminates the virus.


From 2003 to April 1 of this year, the WHO recorded 463 deaths out of 889 human cases across 23 countries, resulting in a case fatality rate of 52%


Zhang noted that the human cases reported in Europe and the US in recent years, since the surge of the virus, have been mild.


Currently, there is no evidence of human-to-human transmission of H5N1.


Zhang stressed that the H5N1 viruses found in cows and in the human case in Texas show no signs of increased adaptation to mammals.


Regarding potential vaccines, Zhang mentioned that there are candidates in development, allowing for swift production should the need arise.


-      AFP

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