Tick testing as a method of controlling Rocky Mountain spotted fever

Abstract

In South Carolina, 1974-1980, only two matches were found between 536 Rocky Mountain spotted fever (RMSF) cases and 965 individuals who submitted ticks that tested rickettsial antigen positive. In neither case did the positive test prevent RMSF. Tick rickettsial positivity rates varied inversely with human RMSF attack rates in different geographic areas. A physician survey established it as unlikely that RMSF ocurred in positive tick submitters (PTS), and that although not recommended, 34% of asymptomatic PTS received prophylactic treatment. Only 18% of positive ticks were engorged. Tick testing appears ineffective in preventing RMSF.