The time between infection by a pathogen and the first appearance of symptoms is known as the incubation period. During this period, the pathogen establishes itself and replicates within the body, but the individual may not yet show any signs or symptoms of the infection. The duration of the incubation period can vary depending on the specific pathogen and the individual's immune response. Understanding the incubation period is important in diagnosing and managing infectious diseases, as it helps determine the potential period of contagion and enables appropriate preventive measures to be implemented.