Incubatory carrier seen in -
Period of communicability of mumps : Usually 4-6 days before the onset of symptoms and a week or more thereafter. The period of maximum infectivity is just before and at the onset of parotitis. Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 165
Cholera
Bubonic plague
Mumps
Measles
Epidemiology