<prompt> Window period is defined as the time taken from:Entry of pathogen to appearance of first clinical symptomsExposure to laboratory detection of diseaseEntry in cell to expulsion of first viral particleEntry to maximum communicability  <response>: Ans. b. Exposure to laboratory detection of disease Ref: Park 23e p99, 22.e p95Window period is defined as the time taken from Exposure to laboratory detection of disease.Window Period: Time between first infection when the test can reliably detect that infection. Disease Transmission: DefinitionsWindow period Time between first infection when the test can reliably detect that infection In antibody-based testing, the window period is dependent on the time taken for seroconversionIncubation periodQ Time interval between invasion by an infectious agent and appearance of the first sign or symptom of the disease in questionMedian incubation periodQ Time required for 50 of cases to occur following exposureGeneration timeQ Time taken for a person from receipt of infection to develop maximum infectivity Roughly equal to the incubation period of the diseaseLatent periodQ Period from disease initiation to disease detection, Used in non-infectious diseases as equivalent of incubation periodSerial intervalQ Gap in onset between primary case first case in the community and secondary case case devetoping through infection from the primary case By collecting information on series of secondary cases with serial intervals, one can guess the incubation period of a diseasePeriod of communicabilityQ Time during which an infectious agent may be transferred directlyindirectly from an infected person to another person, from infected animal to man or from an infected person to animal, including arthropods An important measure of communicability is secondary attack rate 