Medical and infectious disease specialists from Harvard University have expressed concern about the growing incidence of bird flu outbreaks in the United States and have warned of the prospect of a human pandemic.
Bird flu, or H5N1 avian influenza, has been circulating across North America since 2022, infecting birds, livestock, wildlife, pets, and humans from April 2024.
According to the US Centre for Disease Control and Prevention (CDC), there have been 70 documented human cases in the US since April 2024, one of which resulted in death. 41 cases were associated with exposure to infected dairy cows and 26 with exposure to infected poultry.
Despite the fact that there are no known instances of human-to-human transmission, with the CDC categorising the immediate risk to the general public from bird flu as “low”, some scientists worry that it is only a matter of time.
One Harvard scientist pointed to the recent report of H5N1-infected cats in the households of two infected dairy farm workers, as an indication that humans can transmit the virus.
Director of the Ragon Institute of Mass General at Massachusetts Institute of Technology and Harvard, Bruce Walker said: “I think we’re all wondering whether this is a minor blip or if we are facing what may turn into an existential threat.”
While human manifestations of the disease remain mild in form, with few hospitalisations documented, Harvard scientists have flagged enhanced surveillance as an important tool in controlling the spread of the disease and managing it’s development.
“There is a need for urgent, escalated, and coordinated national, state, and municipal surveillance across sectors,” infectious disease specialist, professor Jacob Lemieux argued.
With pauses in federal funding announced by Trump’s government, Lemieux admitted there is a lot of “uncertainty” surrounding the future of bird flu surveillance efforts, which he cited as critical tool in managing the influenza’s development in the human population.
Since the first detection of bird flu in China in 1996, H5NI has been subject to a long history of transmission through multiple bird and mammal species, with the jump into dairy cows documented in the US last year and the first sheep case reported just last week in England.
Human bird flu pandemic
This ongoing development has been cited as a major cause of concern for some infectious disease experts, including Lemieux, who believes we are on the cusp of a major outbreak of bird out among humans. He explained:
“There are a few factors about H5N1 that point to an increasingly risky and uncertain situation. Increased activity has been sustained for over a year, so the virus does not seem to be going away.
“The infection is spreading across domestic and wild animals and spilling over into humans. Human cases have escalated since last year, when the first outbreak occurred in cows.
“In infectious diseases, we have a saying that resistance is a function of time and titer [concentration], meaning that the ability for a pathogen to evolve depends on time under pressure and size of the reservoir.
“The virus has been with us for several years in multiple species, and the reservoir is large. I think we are living next to a volcano, and it may erupt or it may not. But we need to prepare for the possibility of a pandemic.”
