Diphtheria on Skid Road, Seattle, Wash., 1972-75.

From July 1972 to December 1975, an unusual outbreak of diphtheria in Seattle, Wash., resulted in a total of 558 cases and carriers, mostly among heavy alcohol users. Skin infections were predominant. Four white men died. The highest attack rate was among native American Indians. Environmental contamination and poor personal hygience were believed to be important in continuation of the epidemic, but could not be proved. Control measures included casefinding, isolation and quarantine, sanitizing dwelling units and mass immunization with Td toxoid. The high-risk geographic area was the city's Skid Road. This area continues to be the reservoir of continuing infection, but not all population subgroups there have been at equal risk. Spread to other geographic areas of the city and county has been minimal and remains under control.