Fatal influenza B infections: Time to reexamine influenza research priorities

摘要

Influenza A viruses (IAVs) are zoonotic pathogens that sometimes establish long-term lineages in humans and other mammalian hosts. New introductions of influenza genes or whole viruses from animal reservoirs can result in viruses with an exceptionally virulent pheno-type. After a period of adaptation and development of population immunity, however, the descendents of pandemic viruses rarely cause severe illness and mortality through direct viral damage in immunocompetent hosts [1, 2]. Instead, exacerbation of a preexisting, chronic illness or virus-mediated impairment of host defenses facilitating bacterial su-perinfection account for most fatalities. Selwyn Collins of the US Public Health Service, who refined the terms by which we classify outcomes after influenza, expressed this view as, "In fact, influenza may well be thought of as not a killing disease except by the intervention of pneumonia or the presence of chronic disease in a patient" [3].