Carrier stage is seen in -
Man is the only known reservoir of polio infection. It is the mild and subclinical infection that plays a major role in the spread of infection. They constitute the submerged poion of the iceberg of disease. Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 224
Polio
Cholera
Peusis
Plague
Epidemiology