Rickettsia conorii isolated from Rhipicephalus sanguineus introduced into Switzerland on a pet dog

A tick/rickettsial survey in a household near Geneva, Switzerland, revealed that 30 (40%) of 75 nymphs and adults of the brown dog tick, Rhipicephalus sanguineus, were infected with a rickettsial agent biologically and antigenically indistinguishable from R. conorii, the causative agent of boutonneuse fever. Introduced in 1979 from either southern France or Italy by the family's pet dog, the tick infestation had steadily increased until 1981 when control measures were initiated. During 1980 and 1981, four persons associated with the household's pet dog contracted a febrile illness diagnosed as boutonneuse fever.