California has recorded its third case of bird flu in dairy farmers in just three weeks, making it the seventeenth case of H5N1 flu in humans in the US since March.
CDC officials announced that the latest patient is experiencing mild symptoms, including eye redness and eye infection, and that none of the three cases required hospitalization.
Experts believe the infection was spread through the dairy cows with which each patient comes into close contact every day. The patients did not know each other and there is so far no evidence that the infection is spreading from person to person.
According to the CDC, more cases are likely to occur in the coming months given the speed at which bird flu is spreading among hundreds of dairy herds in at least fourteen states.
The agency has received more specimens from two other Californians who are suspected of having bird flu, but they must undergo confirmatory testing by the CDC to verify the results.
While the agency insists the risk to the public remains low, experts have expressed fears that all signs point to the virus’s ability to cause a potential pandemic not unlike that of Covid-19.
At least 250 livestock herds in 14 states have been affected by bird flu since the spring, resulting in at least 18 human cases since 2022
CDC researchers studied the genetic makeup of each virus sample taken from patients and found no signs of mutations that would make the virus more likely to infect or spread between people, or that would make it resistant to antiviral drugs.
Infections in people who have close contact with animals are to be expected, the CDC said, and do not change the message to the public that the overall risk is low.
But outside experts are increasingly concerned that as the virus continues to spread, it will not only sicken more farmers but also gain the ability to better infect people on a larger scale.
Dr. Rick Bright, former deputy secretary for preparedness at the Department of Health and Human Services, said that because the virus spreads among both birds and cows on farms, “the chance of infecting a human increases.”
Dr. Bright added: ‘We don’t know how many cows have been infected, we don’t know how many people have been exposed… If we haven’t contracted the virus before it mutates to be efficiently transmitted from person to person, all bets are off when it comes to being able to control it.’
The virus is rampant in California’s dairy herds, raising the specter of a broader outbreak among farmworkers in the state.
Farms are reporting as much as 50 to 60 percent of their herds are infected and about 15 percent of the cows die.
According to the California Dairy Quality Assurance Program, “As the number of infected herds increases, producers are understandably concerned. They want to know how to prevent the disease from entering their flock and how to best manage the disease if it does happen.”
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The patients in California have suffered from watery, infected eyes, low-grade fever and runny nose.
When five poultry workers became infected in July, they experienced the same symptoms and some breathing problems and, like those in California, did not need to go to the hospital.
However, symptoms can vary in severity and include flu-like symptoms, pain, shortness of breath, eye inflammation, diarrhea, nausea and vomiting. It may resemble an upper respiratory infection from flu.
In the most severe cases, bird flu can lead to pneumonia and breathing problems.
Infected animals shed the virus in their saliva, mucus and feces which can end up in water, soil and various hard surfaces where it can linger for up to 48 hours depending on air temperature and humidity.