(First published: May 16, 2024, Updated: September 10, 2024)
Note: Information in this article is accurate at the time of original publication. For the latest information on H5N1, we recommend visiting the websites of the Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO), and your state and local government.
Avian influenza A (H5N1), or avian influenza, has killed millions of wild birds in the United States, as well as caused sporadic outbreaks among poultry and ongoing outbreaks among cattle in multiple states. caused a trend. The virus is not known to be transmitted from person to person, but 15 cases of human infection have been reported in the United States since 2022, when the first person became infected after exposure to poultry. The remaining incidents occurred in 2024.
The latest infection, confirmed in Missouri in September, is the first time a person has developed the disease despite no reported contact with a sick animal, and how did they become infected? A question arose. Other avian influenza infections have occurred in the United States among people who worked on farms exposed to sick poultry or cattle.
So far, people infected with bird flu have reported mild symptoms. Several people experienced eye infections, and others reported flu-like symptoms including chills, cough, fever, sore throat and runny nose, according to the Centers for Disease Control and Prevention (CDC).
Meanwhile, the good news is that H5N1 is not currently considered a significant public health threat in the United States. The CDC classifies the risk to the general public as “low,” including monitoring the spread of the virus within jurisdictions where the virus has been confirmed in either animals or people, or among people. We continue to monitor the situation closely. .
“In the short term, there's very little threat,” said Dr. Scott Roberts, an infectious disease expert at Yale University. “But in the long term, over the next few years or even decades, I'm more concerned,” he says, citing two reasons. For one, the mortality rate (or deaths) of the nearly 900 people around the world who contracted bird flu between 2003 and 2024 was about 50%.
But Dr. Roberts said 50% may be an overestimate, adding that some people may have no symptoms, only mild symptoms, or may not seek care for their symptoms. He also noted that if the virus does spread to humans, the rate could be significantly lower if preventive approaches and treatments, including vaccines, become widely available.
Another reason for concern is that avian influenza has been detected in new animal species. In addition to the relatively new outbreak of avian influenza viruses in cattle, sporadic infections were detected in some wild mammals in Canada and the United States in 2022. It can spread between humans,” Dr. Roberts said.
Below, Dr. Roberts answers eight common questions people have about bird flu.
