WHO concerned at H5N1 bird flu transmission to mammals

The World Health Organization (WHO) has voiced grave concern regarding the increasing dissemination of the H5N1 bird flu virus, citing millions of chicken deaths since its emergence in early 2020, with recent cases indicating cross-species transmission to mammals, including domestic cattle in the United States, thereby increasing the potential risk of transmission to humans.

Jeremy Farrar, Chief Scientist at the WHO, expressed his apprehension during a media briefing held in Geneva, terming the situation worrying.

The addition of goats and cows to the list of susceptible animals last month has startled experts, as they had not previously considered them at equal risk to birds for contracting the flu.

In April 2024, US officials reported a case of bird flu transmission from pets in Texas, although the patient is currently recuperating. So far, cases of domestic animal infection have been recorded in 16 locations across 6 states in the United States.

Farrar noted that a variant of H5N1, referred to as A, has triggered animal epidemics globally. He warned that the virus is now crossing species barriers, spreading from infected ducks and chickens to mammals. The foremost concern is its potential evolution to infect humans and subsequently develop the capability for human-to-human transmission.

While there is currently no evidence of human-to-human transmission, Farrar highlighted the heightened risk posed by domestic animals in the United States, stressing the need for intensified monitoring to track the disease spread and assess its impact on humans.

Over the past two decades, there have been numerous human cases of bird flu infection, with an unusually high fatality rate due to the absence of natural immunity against the virus. Between 2003 and 2024, WHO records indicate 889 human cases of H5N1 across 23 countries, resulting in 463 fatalities.

Farrar called for urgent research and development of vaccines and treatments against H5N1, acknowledging the critical role of preparedness in combating the virus.

He concluded by saying, "It's sad to say, but if I die from this virus, that will be the end of me, but when I go around people and transmit this virus to someone else, that's the end of me. The journey will begin again."