Medical microbiology is a discipline of medicine concerned with the prevention, diagnosis, and treatment of infectious diseases. It is a broad subset of microbiology that is applied to medicine. Furthermore, this branch of science investigates diverse clinical applications of microorganisms for health improvement. Infectious disease is caused by four types of microorganisms: bacteria, fungi, parasites, and viruses, as well as one type of infectious protein termed prion. A medical microbiologist examines pathogens' features, means of transmission, infection, and growth mechanisms. Other responsibilities may include identifying potential community health hazards, monitoring the evolution of potentially virulent or resistant microbial strains, educating the public, and assisting in the development of health practices. They may also help in the prevention or control of disease outbreaks and epidemics. Some medical microbiologists research common, non-pathogenic species to see if their traits can be used to generate antibiotics or other treatments.