<prompt> What is true regarding Diphtheria ?Nasal carriers are more dangerous than casesImmunization prevent carrier stateCases are most impoant as source of infectionHemagglutination test has been replaced by Schick test  <response>: Diphtheria Causative agent - Corynebacterium diphtheria, a gram bacilli, non-motile organism . Incubation period 2-6 days Immunization does not prevent carrier state. Carriers are more impoant source of infection dangerous than cases. 