An outbreak of tick typhus in the coastal plain of Israel

13 patients with spotted fever caused by rickettsiae and transmitted by ticks were investigated, of whom 6 were in hospital. The disease was characterized by fever, chills, headache, myalgia and an erythematous maculo-papular rash which began on the palms and soles and spread in a centripetal fashion over the remainder of the body. In 1 case the clinical course was prolonged and severe and was characterized by acute renal failure, massive gastrointestinal bleeding, encephalitis, liver damage and myocarditis. In the 6 hospital cases there was thrombocytopenia of varying degree and duration. The differential count of the white blood cells showed a pronounced shift to the left and in 5 cases a marked lymphopenia was found. The diagnosis was confirmed in all cases by a significant rise in spotted fever antibodies. In 3 cases guinea-pigs were inoculated; they showed a rise in temperature, a positive scrotal reaction and a high titre of the complement-fixation test for spotted fever antibodies. Rickettsiae were found in smears and histological sections of the tunica vaginalis of the guinea-pigs examined. In 2 dogs belonging to patients a positive complement fixation test for spotted fever antibodies was found. In the last 20 years no cases of spotted fever transmitted by ticks have been reported in Israel. All the patients in this series came from the Sharon area.