Influenza

Influenza is a highly contagious virus that causes an acute respiratory tract infection. Disease occurs in yearly outbreaks in humans, lasting 2–6 weeks in length. Influenza A and B predominate in these outbreaks, with more severe disease occurring with Influenza A. Additional infections with avian subtypes of influenza have also occurred in humans in the past decade, with notably increased morbidity and mortality. Vaccination is the mainstay for preventing disease. Antiviral drugs may be effective in decreasing duration and severity of disease, but evolving resistance has narrowed treatment options. This chapter provides a broad overview of influenza, from basic virology to epidemiology, disease, treatment, and prevention.