<prompt> All are true for Point source epidemic exceptEpidemic curve rises and falls sharplyClustering of cases within a short period of timePerson-to-person transmissionAll cases usually develop within one incubation period  <response>: EPIDEMIC: Definitions of epidemic: Occurrence of no. of cases of a disease clearly in excess of normal expectancy NE1. Normal expectancy is derived by looking at average of no. of cases of the disease in previous 3 5 years in that geographical area2. If NE zero, even one case is considered epidemic 