This is a sub-specialty of Internal Medicine, and involves further training beyond that of a general physician.
Sites listed here will relate to the medical specialty of Infectious Diseases, and will be of interest primarily to practitioners in that field.

NB Sites about infectious diseases themselves belong in Health/Conditions_and_Diseases/Infectious_Diseases , and sites about the causative agents belong in Science/Biology/Microbiology.
Sites with a focus on tropical diseases belong in Health/Public_Health_and_Safety/Tropical_Health/.