State health officials announced the death Monday, and the Centers for Disease Control and Prevention (CDC) confirmed it was the first death from bird flu in the United States.
Health officials said the person was over 65 years old, had underlying medical conditions and had contact with sick and dead birds in a backyard flock. They also said genetic analysis suggested the bird flu virus had mutated inside the patient, which could have led to more serious illness.
Few details about the person have been released.
Since last March, 66 confirmed bird flu infections have been reported in the United States, but previous cases have been mild and most were detected in farm workers exposed to sick poultry or dairy cows.
A death from bird flu was not unexpected, virological experts said. There have been more than 950 confirmed bird flu infections worldwide since 2003, and more than 460 of those people have died, according to the World Health Organization.
The avian flu virus “is a serious threat and has always been a deadly virus,” said Jennifer Nuzzo, director of the Pandemic Center at the Brown University School of Public Health in Rhode Island. . “It’s a tragic reminder of that.”
Ms. Nuzzo noted that a Canadian teenager became seriously ill after being infected recently. Researchers are still trying to assess the dangers of the current version of the virus and determine what makes it hit some people harder than others, she said.
“Just because we have seen mild cases does not mean future cases will continue to be mild,” she added.
In a statement, CDC officials described the death in Louisiana as tragic, but also said “there are no concerning virological changes actively spreading in wild birds, poultry or cows that would increase the risk to human health.
In two of the recent U.S. cases — an adult in Missouri and a child in California — health officials have not determined how they caught the virus. The origin of the Louisiana person’s infection has not been considered a mystery. However, this was the first human case in the United States linked to exposure to backyard birds, according to the CDC.
Louisiana officials say they are not aware of any other cases in their state, and U.S. officials have said they have no evidence the virus is spreading from person to person.
H5N1 avian influenza has spread widely among wild birds, poultry, cows and other animals. Its growing presence in the environment increases the chances that people will be exposed and potentially catch it, authorities said.
Authorities continue to urge people who come into contact with sick or dead birds to take precautions, including wearing respiratory and eye protection and gloves when handling poultry.
