An infectious disease specialist focuses on the treatment of infectious diseases, according to the American College of Physicians. Infectious disease specialists typically train as doctors of internal medicine or pediatrics before completing two to three years of specialized training in infectious diseases.
Infectious disease or ID doctors have extensive knowledge of bacteria, viruses, fungi and parasites and how they can cause infections of sinuses, heart, brain, lungs, urinary tract, bowel, bones and pelvic organs, according to the American College of Physicians. ID doctors are also experts in the use of antibiotics, in immunology, and in the epidemiology of infectious diseases. Many ID doctors also specialize in the treatment of patients with human immunodeficiency virus infections.