Scientists suspect the H5N9 strain emerged through reassortment—an unpredictable genetic mixing of flu viruses within co-infected hosts. This discovery is significant because reassortment events ...

When two or more strains of a virus infect the same person, they can exchange genetic material and create new, more dangerous variants of a disease through a process called reassortment.

There are concerns about a more dangerous virus emerging, combining bird flu and seasonal flu in a process called reassortment. “I am very worried about H5N1 in patients that are being treated ...