这个词是什么意思？
Species of the genus BETAINFLUENZAVIRUS 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.
中文名称索引；定义为 MeSH 英文原文，尚未逐条译审。MESH:D009981 · MeSH 2026。
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