First bird flu death in US is stark warning

Nuzzo says it’s very possible that the Louisiana patient’s pre-existing health conditions contributed to the severity of his illness, but he also points to the case of a teenager in Canada who was hospitalized with bird flu in November.

The 13-year-old girl was first seen at the BC emergency room with a fever and conjunctivitis in both eyes. She was sent home without treatment and later developed cough, vomiting and diarrhea. A few days later, she found herself in the emergency room in respiratory distress. She was admitted to the pediatric intensive care unit and suffered respiratory failure, but eventually recovered after treatment. According to a case report published in the New England Journal of Medicine, the girl had a history of mild asthma and a high body mass index. It is unclear how she caught the virus.

“What this tells us is that we have no idea who is going to develop mild disease and who is going to develop severe disease, and that is why we need to take these infections very seriously,” explains Nuzzo. “We should not assume that all future infections will be mild. »

There is another clue that could explain the severity of the cases in Louisiana and British Columbia. The virus samples from the two patients showed some similarities. For one, both were infected with the same subtype of H5N1 called D1.1, which is the same type of virus found in wild birds and poultry. It is different from the B3.13 subtype, dominant in dairy cows.

“Right now the question is: Is this a more serious strain than dairy cattle? says Benjamin Anderson, assistant professor of environmental and global health at the University of Florida. So far, scientists don’t have enough data to be sure. A handful of poultry workers in Washington tested positive for the D1.1 subtype, but those individuals had mild symptoms and did not require hospitalization.

“In the case of the Louisiana infection, we know that this person had comorbidities. We know this person was an older person. These are factors that already contribute to more serious outcomes when it comes to respiratory infections,” says Anderson.

In the Louisiana and British Columbia cases, there is evidence that the virus may have evolved in both patients to produce more severe illness.

A CDC report from late December found genetic mutations in the virus taken from a Louisiana patient that may have allowed it to enhance its ability to infect the upper respiratory tract of humans. The report states that the observed changes were likely generated by virus replication throughout the patient’s illness rather than transmitted at the time of infection, meaning the mutations were not present in birds to which the person was exposed.

Writing in the New England Journal of Medicine, the team that cared for the Canadian teenager also described “worrying” mutations found in her viral samples. These changes could have made it easier for the virus to bind to and enter cells in the human airways.

In the past, bird flu rarely spread from person to person, but scientists worry about a scenario in which the virus acquires mutations that make human transmission more likely.

Currently, people who work with birds, poultry or cows, or are exposed to them recreationally, are at higher risk of contracting bird flu. To prevent illness, health officials recommend avoiding direct contact with wild birds and other animals infected or suspected of being infected with the avian flu virus.