A new strain of bird flu, H5N9, has been detected for the first time in the United States, raising concerns about how it continues to spread.

The US Centers for Disease Control and Prevention (CDC) has said in a routine flu update that two people, in Wyoming and Ohio ...

Scientists are particularly concerned about a process called “reassortment,” The Washington Post reported, where different flu strains mix in infected animals, creating new versions of the virus.

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 ...

This latter process is known as genetic reassortment, and it usually happens when an organism is infected with at least two different viruses at the same time. Some experts suspect that H5N9 may ...

"Genetic testing showed this H5N9 was different from historical samples and was, in fact, a reassortment." (Reassortment is the process by which influenza viruses swap gene segments, according to ...