Infections are diseases caused by pathogenic microorganisms such as bacteria, viruses, fungi and protozoa. They can affect various organs and systems of the body. Infections can spread through air, contact, food, water, and other mechanisms.

The symptoms of infections vary depending on the type of pathogen and the organs affected. These may include fever, cough, runny nose, pain, swelling, and other manifestations. Infection prevention includes hygiene, vaccination, isolation of patients and antiseptic measures.