The First US Bird Flu Death Is a Stark Warning

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

A 13-year-old girl initially presented to an emergency department in British Columbia with fever and conjunctivitis in both eyes. She was discharged home without treatment and later developed cough, vomiting and diarrhea. A few days later, she was back in the emergency room with 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 an elevated body mass index. It is unknown how she contracted the virus.

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

There is another clue that may explain the severity of the cases in Louisiana and British Columbia. Viral samples from both patients showed some similarities. First, 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, which is dominant in dairy cows.

“The question right now is, is this strain more severe than the dairy cattle strain?” says Benjamin Anderson, assistant professor of environmental science and global health at the University of Florida. Scientists don’t yet have enough data to know for sure. Several poultry plant workers in Washington tested positive for the D1.1 subtype, but these people had mild symptoms and did not require hospitalization.

“In the case of the infection in Louisiana, we know that this person had underlying health conditions. We know that this man was an elderly man. These are factors that contribute to more severe consequences even when it comes to respiratory infections,” says Anderson.

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

A CDC report for the end of December discovered genetic mutations in a virus taken from a Louisiana patient that may have given it an increased ability to infect humans’ upper respiratory tract. The report said the observed changes were likely caused by virus replication throughout the patient’s illness, rather than being passed on during infection, meaning the mutations were not present in the birds the person came into contact with.

I am writing to New England Journal of MedicineThe team who cared for the Canadian teenager also described “worrying” mutations found in her viral samples. These changes could allow the virus to more easily bind and enter cells in the human respiratory tract.

Bird flu has rarely spread from person to person in the past, but scientists fear a scenario in which the virus acquires mutations that make transmission to humans more likely.

Currently, people who work with or have recreational contact with birds, poultry or cows are at higher risk of contracting avian influenza. To prevent illness, health officials recommend avoiding direct contact with wild birds and other animals infected or suspected of being infected with avian influenza viruses.