This year, the highly pathogenic (H5N1) avian influenza (AI) virus, which spread among migratory birds, chickens, ducks, and dairy cows in the United States, has raised fears of a pandemic (widespread infectious disease) affecting humans. Scientists are rummaging through bird droppings to prevent an AI pandemic. They believe that by detecting the virus in the droppings, they can identify the first host and trace its movement to block the infection route.
CNN reported that as H5N1 sweeps across dairy cows and poultry flocks in the United States, a government-supported bird droppings analysis research project has become increasingly important, stating that it will play a crucial role in providing early warnings against the introduction of pandemics globally.
St. Jude Children's Research Hospital has been conducting a bird droppings analysis research project for 40 years with the support of the National Institutes of Health (NIH). Designated as a cooperative center for AI viruses by the World Health Organization (WHO) in 1975, St. Jude Children's Research Hospital is a leading institution studying the exchange of viruses between humans and animals. Robert Webster, a professor emeritus at the children's research hospital, has been analyzing bird droppings for the presence of AI viruses since 1985 in Delaware Bay, located between New Jersey and Delaware.
Every warm May, millions of shorebirds and gulls briefly stop at Delaware Bay before migrating to their summer breeding grounds. They do this to feed on the thousands, if not tens of thousands, of eggs laid by horseshoe crabs during spawning season. After consuming the protein- and fat-rich horseshoe crab eggs, the birds excrete in this area. Professor Webster found AI viruses in 20% of the droppings. He tracked the AI virus based on the migration of shorebird flocks along the Atlantic, connecting South America and northern Canada. He also discovered nearly all known AI subtypes in bird droppings, excluding two.
Webster previously revealed that the source of the AI virus in 1957 was the digestive tract of wild ducks, establishing that this virus could infect humans, which made him a global authority on AI virus research. Now, at 92 years old, Webster is replaced by his students at St. Jude Children's Research Hospital, Pamela McKenzie and Patrick Seiler, who visit Delaware Bay annually to collect bird droppings.
McKenzie told CNN, "Delaware Bay seems like a treasure trove for avian influenza virus research," and stated, "While we haven't found any novel viruses yet, if viruses are discovered in the droppings left by the birds, we will be able to identify the birds' migration routes and provide early warnings before pandemics are introduced globally."
The H5N1 avian influenza virus, as its name suggests, originally infected only birds like migratory birds and poultry, but it has recently spread to mammals. Cases of infection among farm workers who have come into contact with dairy cows have raised alarms for U.S. health authorities. According to the Centers for Disease Control and Prevention (CDC), as of the 17th, 58 dairy farm workers in the United States tested positive for the H5N1 virus.
Researchers at St. Jude Children's Research Hospital have not yet found H5N1 among the bird droppings collected from Delaware Bay. Instead, they recently discovered a new AI virus named D1.1 in a flock of teal over the past two months. It is genetically related to the H5N1 virus that infected a teenager in Canada on the 18th of last month. The AI virus that has spread among dairy cows recently has a genetic subtype of B3.13.
The researchers believe that D1.1 is a recombinant virus created when two viruses simultaneously infiltrated the same animal and exchanged genes. Based on this, they confirmed that the D1.1 genetic subtype virus is associated with the migratory routes of wild birds that pass through central Canada and extend along the Mississippi River to the Gulf of Mexico. They also discovered that the H5N1 outbreak that began in North America in 2021 was caused by shorebirds migrating along the Atlantic and Pacific migratory routes.
Researchers at St. Jude Children's Research Hospital argued that the results indicate that wild birds in North America are emerging as new virus reservoirs, and monitoring migrating birds will be crucial in preventing future outbreaks. They plan to visit Delaware Bay again next May to collect new bird droppings. Lisa Kercher, a doctor at the hospital, noted, "Flocks of birds stop at Delaware Bay to recharge their energy, and in the process, they spread the AI virus around the area. To know what will happen in the future and whether the H5N1 virus will mutate to pose a danger to humans, we have no choice but to continue tracking their routes."