Farm workers exposed to infected dairy cows have been found to carry antibodies to avian influenza
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There may be more human cases of bird flu in the US than we thought. Health departments in both states conducted blood tests on workers at dairy farms known to have taken in infected cattle, and found that about 7 percent of them had antibodies to the disease. They included people who had never had flu symptoms.
Since March, a bird flu virus known as H5N1 has been circulating in dairy cows across the US. so far, 446 cows 15 US states have tested positive for the virus. since april 44 people In the USA they have tested positive for the influenza subtype which includes H5 – H5N1. But all of them one of those cases It has occurred in poultry or dairy farm workers infected with H5N1.
To better understand how much agricultural workers have contracted the virus, The US Centers for Disease Control and Prevention (CDC) collaborated with state health departments To collect blood samples from 115 people working on dairy farms with H5N1-infected cows in Colorado and Michigan. All samples were obtained between 15 and 19 days after cows on farms tested positive for virus.
Nirav Shah He and his colleagues at the CDC removed seasonal flu antibodies from the samples before testing for the presence of H5N1 antibodies. Antibodies to H5N1 were found in eight of the samples, or 7 percent, suggesting that eight of the workers were unknowingly infected with the virus. Additionally, four workers did not recall having any symptoms.
“This is critical because, prior to this point, (H5N1) testing recommendations have largely focused on symptomatic workers,” he says. Meghan Davis at Johns Hopkins University in Maryland. “When workers don’t know they’re infected, they can inadvertently expose other people in their community to the infection.”
H5N1 is poorly known to infect humans and is not known to transmit between people. However, more than 900 people worldwide They have been reported to have had the virus since 2003, and about half of them have died from it. Each of these infections provides an opportunity for the virus to develop mutations it can be more dangerous for people.
“In public health we need to cast a wider net of what we offer a test,” Shah said at a press conference today. “Moving forward, CDC is expanding the testing recommendation to include workers who have been exposed (to H5N1) and are asymptomatic.”
The agency also recommends offering antiviral medication to symptomatic workers with high-risk exposure, such as those on dairy farms who may splash raw milk on their faces. That way, if they contract the virus, they will have a smaller amount circulating inside them, which reduces the risk of spreading it to other people. “The less room we give this virus to run, the less opportunity we give it to change,” Shah said.
This data also highlights that many cases of H5N1 are going undetected – a concern that public health officials have long suspected to be true. However, “we cannot speculate on how many cases may be unidentified” until we have more data, Shah said.
The CDC is now analyzing an additional 150 blood samples collected from veterinarians who work with cattle. Once these results are available, they should give us a clearer picture of how many cases may have fallen through the cracks, Shah said.
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