Outbreaks of avian flu were reported this week at a poultry facility in Michigan and an egg producer in Texas, and the latest developments with the virus include infected dairy cows in Texas and Kansas, as well as the first reported cases of avian flu being transmitted from mammals to humans.
Health officials say the risk to the general public remains low, but concerns are growing after the largest U.S. raw egg producer reported an outbreak.
Mandy Cohen, director of the U.S. Centers for Disease Control and Prevention, told The Associated Press on Wednesday that the center takes bird flu seriously but stressed that the virus is already well studied.
“The fact that the virus is present in cattle definitely raises our level of concern,” Cohen said, noting that farmworkers who work with cattle as well as birds may need to take precautions.
The good news is that “this is not a new strain of the virus,” Cohen added. “It’s something we know about and we’ve studied, and frankly, we’ve been preparing for avian flu for 20 years.”
Some influenza viruses primarily infect humans, while others occur primarily in animals: avian viruses spread naturally in wild waterfowl, such as ducks and geese, and then to chickens and other poultry.
The avian influenza virus that is currently attracting attention (type A H5N1) was first identified in 1959. Like other viruses, it has evolved over time, producing new versions.
Since 2020, the virus has spread to many more animal species in numerous countries, including dogs, cats, skunks, bears, and even seals and dolphins.
In the United States, this type of avian flu has been found in wild birds, commercial chicken farms and household chickens in every state. Tens of millions of chickens across the country have died from the virus or have been culled to prevent the spread of the disease.
U.S. officials announced last week that the virus had been found in livestock, and as of Tuesday it had been found in dairy herds in five states: Idaho, Kansas, Michigan, New Mexico and Texas, according to the U.S. Department of Agriculture.
From the archives: Dallas Zoo puts some birds back on display as bird flu threat subsides
The bird flu was first recognised as a threat to humans when it emerged in Hong Kong in 1997. Over the past 20 years, about 900 people have been diagnosed with bird flu worldwide and more than 460 have died, according to the World Health Organisation.
There have been only two cases in the United States, neither of which resulted in deaths.
In 2022, an inmate taking part in a work program at a poultry farm in Montrose County, Colorado, became infected while killing infected birds. He only experienced fatigue and later recovered.
This week, health officials in Texas announced that a person who had come into contact with the cows had been diagnosed with avian flu, with the only reported symptom being bloodshot eyes.
Symptoms are similar to other types of influenza, including coughing, body aches, and fever, but some people may not experience any noticeable symptoms, while others may develop severe, life-threatening pneumonia.
The majority of cases are contracted directly from birds, but scientists are on the lookout for signs that the virus is spreading among people.
There have clearly been some such cases, most recently in Asia in 2007. In each cluster, infection spread within households from a sick person in the household.
U.S. health officials stress that the current public health risk is low and there is no indication that avian flu is spreading from person to person.
Darin Detwiler, a food safety and policy expert at Northeastern University, said it’s too early to quantify the potential economic impact of an avian flu outbreak, but many of the recent trends are worrying, especially the virus’s ability to spread from species to species.
“We don’t have a magic force field, an invisible shield that protects us from land and water runoff impacting other species,” Detwiler said. “The concern is how this will impact other markets, the egg market, the beef market.”
Detwiler added that consumers could eventually see higher prices if the outbreak is not contained quickly, and that some industries could experience a “reputational damage” if the outbreak continues, affecting export industries.
Mark Dresner, a spokesman for the American Egg Association, said the egg industry is already facing tight supplies due to detections of bird flu in late 2023 and early January, coinciding with the Easter season when Americans typically consume an average of 3 billion eggs.
Still, despite the Texas outbreak that led to the culling of about 2 million chickens, there are an estimated 310 million egg-laying hens in the United States, and wholesale egg prices are down about 25% from their February peak, Dresner said.
Sean Murphy, The Associated Press
Associated Press writers Jonathan Poet in Philadelphia, Mike Stobb in Atlanta and videojournalist Sharon Johnson contributed to this report.
Correction, April 24, 2024, 4:05 PM: An earlier version of this story misspelled the first name of Darin Detwiler, a food safety and policy expert at Northeastern University.
