Focus of human parasitism by the brown dog tick, Rhipicephalus sanguineus (Acari: Ixodidae).

Throughout most of its range, the brown dog tick, Rhipicephalus sanguineus (Latreille), prefers dogs as a host, but human bites occasionally occur in the Mediterranean region and Central America; historically, this species has rarely bitten humans in the United States. A focus of 15 human bite cases by this tick is reported from four Air Force bases located within 200 miles of each other in north central Texas and southwestern Oklahoma. The sudden appearance of numerous documented bite cases indicates that either the species is becoming more anthropophilic in this area or than an introduction of a more human adapted population of R. sanguineus has occurred. The species is a known reservoir and vector of Ehrlichia canis, the causative agent of canine ehrlichiosis in dogs. The presence of an anthropophilic strain of R. sanguineus in the United States may lead to increased exposure to E. canis and thus an increase in the incidence of human ehrlichiosis.