The time interval time interval between invasion by an infectious agent and appearance of the first sign or symptom of the disease is

The incubation period is the time interval between invasion by an infectious agent and appearance of the first sign or symptom of the disease in question.Median incubation period: time required for 50% of the cases to occur following exposure.Latent period: The period from disease initiation to disease detection. Used in non-infectious diseases.Serial interval: The gap in time between the onset of the primary case and the secondary case is called the serial intervalGeneration time: The interval of time between receipt of infection by a host and maximal infectivity of that host.Secondary attack rate: Number of exposed persons developing the disease within the range of the incubation period.