<prompt> True about epidemology of influenza -Asymptomatic seen rarelyIncubation period 10-12 hrsPandemic rareExtra human reserviour seen  <response>: Influenza is an acute respiratory tract infection characterised by sudden onset of chills,malaise,fever,muscular pain anx cough. Influenza A strains are pandemic.Incubation period 18 to 72 hours Major reservoirs exists in animals and birds Reference; Park;s Textbook of preventive and social medicine, 24th edition.Pg no. 163,164 