Infection is the result of invasion of the body by microorganisms, including bacteria, viruses, or fungi.

Not all microorganisms cause infections in the body, and exposure to a disease-causing microorganism does not always result in symptoms. The immune system plays a large role in determining the body’s ability to fight off infection.

Some examples of infection are common cold/sore throat, influenza, cough, recurrent ear infections, urinary tract infection, yeast infection, athlete’s foot, cold sores, HIV, shingles, and parasites.