Last month, researchers published a report in the New England Journal of Medicine (NEJM) detailing how a 13-year-old in Canada fought for her life after contracting a severe bird flu infection from an unknown source. In addition to going on life support with an ECMO machine, the teenager received a plasma exchange and multiple antiviral treatments. But her case didn’t initially start severe. Her symptoms began with double conjunctivitis, also known as pink eye, and turned into a fever and coughing. When she first went to the hospital she tested positive for influenza A — but not the seasonal subtype. Further testing suggested she had a high viral load of a novel influenza A infection, which researchers eventually discovered to be avian flu caused by the H5N1 virus.
As the Centers for Disease Control and Prevention (CDC) explains, bird flu is a disease caused by the influenza A virus. At the same time, recent CDC data shows that seasonal influenza A is rising across the U.S. — specifically the H1N1 (swine flu) and H3N2 strains. While it may just seem like a tiny change in numbers, these differences in flu viruses can mean they are more pathogenic and deadly. But how do researchers know that if a person tests positive for influenza A, it’s not H5N1 avian flu?
