USA This year has seen dozens of cases of human bird flu, all of them mild… so far.
The Centers for Disease Control and Prevention confirmed on wednesday that a patient in Louisiana has been hospitalized with a severe case of avian influenza caused by the H5N1 virus. This marks the first case of serious illness related to the virus in the United States.
The virus has decimated poultry and wild bird flocks across the country and infected more than 800 dairy herds in 16 states. Infected animals have been transmitting the virus to people who come into contact with them. Since April, the United States has seen a total of 61 human cases of bird flu reported in eight states. Of those, 37 were exposed to sick or infected dairy cows, while 21 were exposed to poultry farms and slaughter operations. In those cases, people developed conjunctivitis and mild respiratory symptoms and made a full recovery.
A severe case is important because bird flu has previously been associated with serious illness in other countries, including outbreaks that caused death in up to 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 the CDC has determined that the hospitalized patient, a resident of southwest Louisiana, was exposed to sick and dead birds in backyard flocks. This is the first case of H5N1 bird flu in the US that has been linked to exposure to a backyard flock, rather than a commercial farm.
“While an investigation into the source of this infection is underway in Louisiana, it is believed that the patient reported from Louisiana was exposed to sick or dead birds on his property,” said Demetre Daskalakis, director of the CDC’s National Center for Immunization. . and Respiratory Diseases, during a press conference Wednesday. No other details were available about the source of exposure or the patient’s condition.
A person with bird flu in Missouri was hospitalized in late August, but CDC officials say it was due to underlying medical conditions. The patient had no respiratory symptoms and was not seriously ill from the infection. “In the case of Missouri, we really don’t have the same type of data to support that it was related to their influenza infection,” Daskalakis said.
There are genetic similarities between the Louisiana patient’s virus 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 in another case from Washington state. This variant has also been detected in wild birds and poultry in the US.
This is different from type B3.13, which has been detected in dairy cows, some outbreaks in poultry, and in sporadic human cases in several states. CDC scientists are conducting additional genomic sequencing of the Louisiana patient’s viral sample. Genomic sequencing can identify potentially concerning changes in the virus that would indicate an increased ability to infect humans or spread from person to person.
To date, no human-to-human transmission of H5N1 bird flu has been detected. The CDC says the immediate risk to public health remains low, but those with occupational or recreational exposure to infected animals are at higher risk of contracting the virus. “This means backyard flock owners, hunters and other bird enthusiasts should also take precautions,” the agency said in a statement.