<prompt> The characteristic features of El tor cholera are all exceptMore of subclinical casesMoality is lessSecondary attack rate is high in familyEl tor vibrio is harder and able to survive longer  <response>: Ans. is c i.e., Secondary attack rate is high in family El Tor vibrio . It is much hardier than classical vibrios, capable of surviving in the environment much longer. . The severity of illness is much less, with a large propoion of mild and asymptomatic infections. . Moality is low and the carrier rate is high. . Fewer secondary cases in affected families secondry attack rate is less - Park 