The difference between pathogen and infectious source is as follows: 1. Pathogen: refers to the cause of an infectious disease, such as bacteria, viruses, mycoplasma, chlamydia, etc., focusing on the cause, etiology perspective; 2. Infectious source: is the source of infection, firstly for infectious diseases, and secondly, the source of infection is not bacteria, viruses or mycoplasma, chlamydia, but the source that causes the spread of infectious diseases. If a patient is suffering from an infectious disease, the patient is the source of infection. If an animal, unit or laboratory causes transmission, the animal, unit or laboratory is the source of infection.