H5N1

Genetic structure

H5N1 is a subtype of Influenza A virus. Like all subtypes it is an envelopednegative-senseRNA virus, with a segmented genome. Subtypes of IAV are defined by the combination of the antigenic hemagglutinin and neuraminidase proteins in the viral envelope. "H5N1" designates an IAV subtype that has a type 5 hemagglutinin (H) protein and a type-1 neuraminidase (N) protein. Further variations exist within the subtypes and can lead to very significant differences in the virus's ability to infect and cause disease, as well as to the severity of symptoms.