The United States now he has seen dozens of cases of human bird flu this yearall myths-until now.

The Centers for Disease Control and Prevention confirmed on Wednesday that a patient in Louisiana was hospitalized with a severe case of bird flu caused by the H5N1 virus. This marks the first case of severe illness linked to the virus in the United States.

The virus has decimated flocks of poultry and wild birds across the country and infected more than 800 dairy farms in 16 states. Infected animals spread the virus to people who come into contact with them. Since April, the United States has seen a total of 61 reported human cases of bird flu in eight states. Of those, 37 had exposure to sick or infected dairy cows, while 21 had exposure to poultry and culling operations. In these cases, people developed conjunctivitis and mild respiratory symptoms and recovered fully.

A severe case is significant because bird flu has previously been associated with severe disease in other countries, including outbreaks that resulted in death in 50 percent 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 CDC determined that the hospitalized patient, a southwest Louisiana resident, had exposure to sick and dead birds in backyard flocks. This is the first case of H5N1 bird flu in the United States that has been linked to exposure to a backyard flock. instead of a commercial farm.

"While an investigation into the source of this infection in Louisiana is ongoing, it is believed that the patient who was reported from Louisiana had exposure to sick or dead birds on his property," said Demetre Daskalakis, director of the CDC's National Immunization Center. and Respiratory Diseases, during a press briefing on Wednesday. No other details were available about the source of exposure or the patient's condition.

One person with bird flu in Missouri was hospitalized in late August, but CDC officials say it was because of underlying medical conditions. The patient had no respiratory symptoms and was not seriously ill from his infection. "In the case of Missouri, we don't really have the same kind of data to support that it was related to their influenza infection," Daskalakis said.

There are genetic similarities between the virus from the Louisiana patient and the virus from a teenager in Canada who was hospitalized with H5N1. Scientists have categorized the virus in Louisiana as type D1.1, the same type found in the Canadian patient and another case from Washington state. This variant has also been detected in wild birds and poultry in the United States.

This is different from the B3.13 type, which has been detected in dairy cows, some poultry outbreaks, and in sporadic human cases in several states. CDC scientists performed additional genomic sequencing of the Louisiana patient's viral sample. Genomic sequencing can potentially identify changes in the virus that signal an increased ability to infect humans or be transmitted from person to person.

So far, no person-to-person spread of H5N1 avian influenza has been detected. The CDC says the immediate risk to public health remains low, but those who are occupationally or recreationally exposed to infected animals are at greater risk of coming down with the virus. "This means backyard owners, hunters and other bird enthusiasts should also take precautions," the agency said in a statement.