Avian influenza, which is transmitted by wild, migrating birds, has resulted in the deaths of approximately 8 million turkeys in the United States this year. (Photo by Scott Bauer | Agriculture Research Service, USDA)
Four agricultural workers in southeast Washington have preliminarily tested positive for bird flu after working around an infected poultry flock at a commercial egg farm.
The cases, if confirmed, would mark the first instance of individuals in Washington contracting the virus since officials began observing a significant increase in infected birds and other animals around 2022 in the U.S. Since then, over two dozen human cases have been identified in five other states — all except one associated with contact with infected animals.
Health officials have stressed that the four positive cases in Washington are “presumptive,” pending confirmation and analysis by the U.S. Centers for Disease Control and Prevention.
“We are still conducting an ongoing investigation,” stated Dr. Umair Shah, Washington’s secretary of health, during an online press conference on Sunday.
“At this time, we believe the individuals who received positive results have been exposed to infected poultry. We do not currently have evidence of human-to-human transmission. However, that is still part of our investigation,” Shah added.
The Washington farm workers suspected of having the virus have not been hospitalized, according to state and local health authorities.
Dr. Steven Krager, the local health officer for Benton and Franklin counties, mentioned that the workers exhibited symptoms of mild upper respiratory illness, including a runny nose, sore throat, mild cough, and conjunctivitis, also known as “pink eye.”
The outbreak at a commercial egg farm in Franklin County involves a flock of around 800,000 birds. This marks the first bird flu incident at a commercial poultry farm this year.
Tests conducted on October 15 revealed that the poultry were infected with bird flu. Testing of individuals showing symptoms of the virus was arranged on Friday, with positive results returned late on Saturday, according to Krager.
‘Evolving situation’
The strain of bird flu circulating in the U.S. is officially known as H5 highly pathogenic avian influenza. This disease has led to outbreaks in poultry, dairy cows, and various wildlife throughout the country, including harbor seals in northwest Washington.
The risk to the general public is considered low, as per the CDC. Currently, individuals who spend time around animals at risk of infection are more likely to contract the virus.
However, health officials are monitoring for any changes in the disease that could enable sustained human-to-human transmission or more severe illness in humans. A major concern is that the virus could mutate in ways that facilitate easy transmission among people.
Between 2003 and April of this year, the World Health Organization recorded a total of 889 cases and 463 deaths in 23 countries caused by the H5N1 bird flu virus.
“If we were to look at all avian influenza H5 infections reported since 2003, the case fatality rate is quite high, over 50%,” noted Tao Sheng Kwan-Gett, the state Department of Health’s chief science officer.
“We’re not seeing that here. But that is something that would be very worrisome, and so severity of illness is something that we’ll want to monitor closely,” he mentioned.
Shah reported that 25 people have been tested so far as part of the response in Franklin County, with 12 tests coming back negative.
“This is an evolving situation,” he stated. “There are more individuals that we want to continue our investigation with, and more individuals that we want to potentially test. And that’s what we are currently doing.”
The other five states that have documented bird flu infections in humans are California, Colorado, Michigan, Missouri, and Texas.
As of Friday, a total of 27 cases have been reported across those states since April, according to CDC data. Out of these, 23 were in either California or Colorado. Nationwide, 16 cases have been confirmed as the H5N1 version of the virus.
The lone human case in Missouri is the only one not linked to exposure to infected poultry or cattle in the CDC data.
‘Not unexpected’
Bird flu can devastate poultry flocks, quickly leading to severe illness and death among fowl.
Fall poses a heightened risk for the disease in Washington due to its prevalence among migratory wild birds. Wild birds that migrate north from the lower 48 states in the summer encounter other birds from Asia and Europe, creating a prime environment for the transmission and mutation of bird flu.
“We all anticipate and observe what they bring with them when they come back down,” noted state veterinarian Amber Itle. “It was not unexpected for us to see additional detections of the avian influenza virus again this fall. However, we had hoped it would be a less pathogenic strain.”
Since 2022, Washington has identified avian influenza in 47 poultry flocks. Two were commercial, including the Franklin County outbreak, while the rest were domestic. The other commercial flock consisted of around 1 million birds. Domestic flocks varied in size.
Itle mentioned that the state and agricultural operations are monitoring for bird flu at other poultry and dairy farms near the site of the latest outbreak. She did not provide specific details on the number of farms in the immediate area but stated that there are currently no signs of the virus spreading to dairy cattle.
“This detection we have is a poultry strain, not a dairy strain,” Itle clarified. “We have not detected the virus in dairies in Washington state.”
Most of the birds at the Franklin County farm where the outbreak occurred were euthanized by Sunday, Itle shared. She added that eggs from the site would also be destroyed.
“Your eggs and poultry are safe,” she assured. “No infected or previously infected birds are entering the food supply. They are all being disposed of and will undergo composting to deactivate the virus.”
The U.S. Department of Agriculture has a program to reimburse farmers for losses due to bird flu. However, Itle emphasized that the mass culling of thousands of birds can be emotionally challenging for farm owners and workers, especially as risks from the virus persist on a farm.
There are recommended personal protective equipment guidelines for sites where the disease is present, and the state has protective gear available upon request.
Owners of backyard poultry flocks also need to remain vigilant.
State agriculture officials estimate that around 15% of migrating waterfowl are infected with bird flu and can easily contaminate an environment by landing in a pond, entering a coop, or foraging around bird feeders.
“The most important step you can take if you have backyard poultry is to keep them away from wild waterfowl,” Itle advised. “This is crucial for protecting your birds and yourselves.”
This story was originally published by the Washington State Standard, part of States Newsroom, a nonprofit news network, including the Daily Montanan, supported by grants and a coalition of donors as a 501c(3) public charity.
