Infectious diseases, which occur when microorganisms such as viruses, bacteria, parasites, fungi, etc. enter the body and multiply, can attach to many organs or tissues. In addition, some microorganisms can cause disease by secreting some toxins after they multiply after entering the body or inside the bodyInfection also works in direct proportion to the body's defense mechanism. If the defense mechanism does not work properly, microorganisms entering the body initiate infectious diseases. Factors that reduce the defense mechanism are malnutrition, poor hygiene conditions, immune system deficiencies, chronic diseases, infancy or old age, inadequate vaccination, medical and surgical treatments.