September 20, 2024 — Missouri, USA
A case of bird flu in Missouri has raised concerns after the U.S. Centers for Disease Control and Prevention (CDC) confirmed that the patient was infected with the H5N1 strain of the virus, similar to the one affecting cattle in the United States this year. The patient, who had no known contact with birds or cattle, marks a puzzling development in understanding how this virus spreads.
The viral sequence, uploaded to the GISAID database on Friday, revealed that the virus closely resembles the strain responsible for infecting dairy cattle across 14 states. The CDC and health authorities are investigating how the patient could have contracted the virus without the usual risk factors, such as contact with infected animals or consumption of raw dairy products.
While this is the 14th human infection of H5N1 in the U.S. this year, all previous cases involved individuals who had close contact with animals. What sets the Missouri case apart is the patient’s lack of exposure to potential carriers. Lisa Cox, communications director for the Missouri Department of Health and Senior Services, stated that the patient had no pets and was unsure whether they had consumed pasteurized dairy products.
“This is definitely unusual,” said Dr. Nirav Shah, principal deputy director of the CDC, during a news briefing. “It’s concerning that we don’t see a clear source of infection. But we are monitoring the situation closely.”
The patient, an adult with multiple underlying health conditions, was hospitalized after experiencing chest pain, nausea, vomiting, diarrhea, and weakness. The individual tested positive for an influenza A virus, which was later identified as the H5N1 strain following additional testing.
Although there have been no confirmed cases of human-to-human transmission in this instance, one close household contact developed similar symptoms but was never tested. Another close contact, a healthcare worker, tested negative for the virus.
Scientists analyzing the genetic sequence found no signs of mutations that would make the virus more contagious or severe, which is reassuring. However, some mutations detected could potentially impact vaccine development, making this case noteworthy from a public health perspective.
The CDC has not reported any further cases following the 10-day follow-up period, and both the patient and their contacts have since recovered. However, the agency remains vigilant, continuing its efforts to understand the virus’s behavior and prepare for any future outbreaks.
Public health officials are urging people to remain cautious but not alarmed, emphasizing the importance of monitoring symptoms and seeking medical attention if needed.