<prompt> True about epidemiology of influenza -Asymptomatic seen rarelyIncubation period 10-12 hrsPandemic rareAll ages sex are equally affected  <response>: Influenza is characterised by sudden onset of chills,malaise, fever, muscular pains and cough Influenza A strain is pandemic IP period l8 to 72 hours Affects all ages andboth sexes Reference : Park;s Textbook of preventive and social medicine, 24th edition.Pg no. 163,164 