CDC Confirms First US Case of Severe Bird Flu

USA Already seen dozens of Cases of human avian influenza this yearall of which were tame—until now.

Centers for Disease Control and Prevention Confirmed on Wednesday A patient in Louisiana has been hospitalized with severe avian influenza caused by the H5N1 virus. This marks the first serious case of illness related to the virus in the United States.

The virus has caused widespread deaths of poultry and wild birds across the country and infected more than 800 dairy herds in 16 states. Infected animals are spreading the virus to the people they come into contact with. Since April, the United States has experienced Eight states report 61 human cases of avian influenza. Of those, 37 had contact with sick or infected dairy cows and 21 had contact with poultry farms and culling operations. In these cases, people developed conjunctivitis and mild respiratory symptoms but later fully recovered.

The severe cases are significant because bird flu has previously been associated with severe illness in other countries, including outbreaks that killed up to 50% of cases. From 2003 to 2023, of the 878 people who tested positive for the virus, 458 deaths were reported.

An investigation by the Louisiana Department of Health and the Centers for Disease Control and Prevention determined that the hospitalized patient was a southwest Louisiana resident who had been exposed to sick and dead birds from a backyard flock. This is the first case of H5N1 avian influenza in the United States, linked to exposure to backyard chickens. rather than a commercial farm.

“While the investigation into the source of infection in Louisiana is ongoing, the patient reported in Louisiana is believed to have been exposed to a sick bird in his or her home,” said Demit Daskalkakis, director of the CDC’s National Center for Immunization. or dead birds. No other details about the source of exposure or the patient’s condition were available at this time.

A person in Missouri who contracted bird flu was hospitalized in late August, but CDC officials said it was due to an underlying medical condition. The patient had no respiratory symptoms and was not seriously ill from the infection. “In the case of Missouri, we don’t actually have the same type of data to support that this is related to their flu infection,” Daskalakis said.

The virus from the Louisiana patient is genetically similar to a virus from a teenager in Canada who was hospitalized with H5N1 influenza. Scientists classify the Louisiana virus as D1.1, the same type found in the Canadian patient and another case in Washington state. This variant has also been found in wild birds and poultry in the United States.

This is different from B3.13, which has been detected in dairy cows in several states, in some poultry outbreaks, and in sporadic human cases. CDC scientists are performing additional genome sequencing on viral samples from Louisiana patients. Genome sequencing can identify potentially relevant changes in the virus that could indicate an increased ability to infect humans or spread between humans.

So far, no human-to-human transmission of H5N1 avian influenza has been found. The CDC said the immediate risk to public health remains low, but those who come into contact with infected animals at work or recreation are at higher risk of contracting the virus. “This means backyard chicken owners, hunters and other bird enthusiasts should also take precautions,” the agency said in a statement.