Infectious disease medicine deals with infectious and communicable diseases caused by viruses, bacteria or parasites. An infectious disease physician is one who deals with infectious diseases of all types and in all organs, from the common cold and flu to HIV, respiratory infections, parasitic infections, and some allergies. In some cases, the physician may use preventive medicine; in other cases, antibiotics may be prescribed.

Doctor density varies by specialty and location. The United States has 7,390 practicing infectious disease medicine doctors. Broken out by state, infectious disease medicine doctor density in Alabama is 75, in Alaska is 9, in Arizona is 84, in Arkansas is 27, in California is 780, in Colorado is 106, in Connecticut is 148, in Delaware is 20, in District of Columbia is 113, in Florida is 434, in Georgia is 224, in Hawaii is 25, in Idaho is 8, in Illinois is 324, in Indiana is 109, in Iowa is 61, in Kansas is 40, in Kentucky is 68, in Louisiana is 86, in Maine is 26, in Maryland is 313, in Massachusetts is 444, in Michigan is 198, in Minnesota is 128, in Mississippi is 41, in Missouri is 137, in Montana is 13, in Nebraska is 43, in Nevada is 31, in New Hampshire is 35, in New Jersey is 284, in New Mexico is 47, in New York is 784, in North Carolina is 201, in North Dakota is 15, in Ohio is 258, in Oklahoma is 37, in Oregon is 56, in Pennsylvania is 332, in Rhode Island is 55, in South Carolina is 92, in South Dakota is 11, in Tennessee is 143, in Texas is 395, in Utah is 44, in Vermont is 13, in Virginia is 158, in Washington is 162, in West Virginia is 25, in Wisconsin is 94, and in Wyoming is 7.