Definition: Species of the genus INFLUENZAVIRUS B that cause HUMAN INFLUENZA and other diseases primarily in humans. Antigenic variation is less extensive than in type A viruses (INFLUENZA A VIRUS) and consequently there is no basis for distinct subtypes or variants. Epidemics are less likely than with INFLUENZA A VIRUS and there have been no pandemics. Previously only found in humans, Influenza B virus has been isolated from seals which may constitute the animal reservoir from which humans are exposed.
infection: coordinate IM with INFLUENZA, HUMAN (IM) in humans or ORTHOMYXOVIRIDAE INFECTIONS (IM) in animals; INFLUENZAVIRUS B is also available
Other names Orthomyxoviruses Type B; Influenza Viruses Type B; Influenza B viruses
