Stages of an Infectious Disease
There are four discrete stages of an infectious disease, which are as follows:
1. Incubation period: This denotes the time interval betweenthe entry of infective agent and the onset of clinical mani-festations of disease. During this period, the infective agent after reaching the selective tissue undergoes multiplication.
2. Prodrome period: It is the time during which only non-specific symptoms of disease occur.
3. Specific illness period: The time during which the charac-teristic features of disease occur.
4. Recovery period: The time during which symptomsresolve and health is restored.
Not all the cases that recover become free of organism. Some become chronic carriers and act as sources of infection for others. Though some cases may not develop infection, they can act as a link in the transmission of infection. This is called subclinical infection.