Additional instances of human parasitism by the brown dog tick (Acari: Ixodidae).

Nine cases of humans parasitized by the brown dog tick, Rhipicephalus sanguineus (Latreille), are reported. Eight cases occurred during 1989. Seven of the individuals were from an apparent focus of human biting in northern Texas and southwestern Oklahoma, one case was from San Antonio, Bexar County, Tex., and one case was from Homestead Air Force Base, Dade County, Fla. These cases suggest that the role of R. sanguineus in the transmission of the etiologic agent of canine ehrlichiosis and other pathogenic organisms to humans may be underestimated and warrants investigation.