THURSDAY, Jan. 2, 2025 (HealthDay News) -- A Canadian teen's severe bird flu infection has highlighted growing concerns about the H5N1 virus, commonly known as bird flu, which has seen a steady rise in human cases across the U.S.
According to a news release, the 13-year-old, who was hospitalized in November, had asthma and obesity but was otherwise in good health before catching H5N1. She became critically ill with multiorgan failure and required advanced life support, including extracorporeal membrane oxygenation (ECMO) and continuous dialysis.
The teen recovered after aggressive treatment with three antiviral medications, but the source of her infection is still unknown.
“She had multiorgan failure and was horribly ill,” Dr. Megan Ranney, dean of the Yale School of Public Health, told CNN. “Were those extraordinary treatment modalities not available, she likely would not have lived.”
Her case, published Dec. 31, 2024 in the New England Journal of Medicine, highlights the possible dangers of newer H5N1 variants like D1.1, which have shown genetic changes that could mean they are adapting to humans.
Experts, including Dr. Jennifer Nuzzo of the Pandemic Center at Brown University, have raised alarms about these findings, emphasizing an increased risk of human-to-human transmission.
“This is a very worrisome outcome that we should be much more concerned about happening with other infections,” Nuzzo said.
The U.S. Centers for Disease Control and Prevention (CDC) also published data in the study on the first 46 confirmed human H5N1 infections in the United States this year.
Most cases were mild, linked to exposure to infected animals or raw milk, with symptoms like conjunctivitis and fevers lasting about four days.
However, severe cases, such as the teen in Canada and a recent one in Louisiana, have raised concerns.
What the numbers show:
93% of infections in farmworkers included eye redness or conjunctivitis (42 out of 46 cases).
Nearly 50% of cases involved fevers, while 36% experienced respiratory symptoms.
The average duration of illness was 4 days
66 confirmed human H5N1 cases in the U.S. so far this year
Recent dairy farm testing revealed 7% of workers had evidence of H5N1 infection.
“The risk is really going to come when this gets better at obviously infecting humans, and then we are faced with potential for human-to-human transmission,” Marrazzo said.
Even though there aren’t many human cases, experts say the persistent detection of H5N1 in humans and animals is troubling. “This virus doesn’t miss a beat,” Marrazzo concluded.
More information
The CDC has the current status of the H5N1 virus, commonly known as bird flu.
SOURCE: New England Journal of Medicine, study, Dec. 31, 2024; CNN