Clinical infectious disease process

1; The interval between exposure to an infectious agent and the appearance of the first symptoms

-Microorganism has entered the individual, undergone colonization and begun multiplying.

-Insufficient numbers to cause symptoms

-May last from hours to days to years 

2; The appearance of initial symptoms which are often mild including feelings of discomfort and tiredness.

-Pathogen continues to multiply, and the host begins to experience general signs and symptoms of illness.

-A result of activation of the immune system (pyrexia, pain, soreness, swelling)

3; The pathogen is multiplying rapidly, invading further, affecting tissues at the site of initial colonization and other areas. 

-Development of symptoms specifically related to the pathogen and symptoms related to the protective inflammatory response. 

-Signs and symptoms are at the most obvious and severe. 

4; Individuals' immune and inflammatory systems have in general successfully removed the infectious agent. 

-Symptoms decline 

-May enter a latency phase which is the resolution of symptoms until reactivation at another time, e.g. chicken pox.