Rickettsioses: a continuing disease problem

The rickettsioses continue to constitute major health problems in many areas of the world. Unlike those diseases that are transmissible directly from man to man, the rickettsioses are closely associated with man's environment and are therefore difficult to recognize and require complex strategies for their control. This article is concerned mainly with means for recognition and surveillance of these diseases, since only with reliable background information can a reasonable strategy for prevention and control be developed. Clinical information, while helpful, is insufficient for the identification of rickettsial diseases and for their differentiation from other pyrexias. The need for laboratory support, particularly serological tests, is emphasized. The indirect fluorescent antibody technique (IFA) is at present the most broadly applicable to all of the rickettsioses under the circumstances that exist in problem areas. Therapy of the rickettsioses is based on the use of specific antibiotics, including the tetracyclines and chloramphenicol, but antibiotics should not be used routinely for prophylaxis. Immunization with a live attenuated vaccine is effective against outbreaks of louse-borne typhus. Experimental Q fever vaccines have also given protection against disease but side-effects have limited their use. Action against the arthropod vectors is also important and may consist of insecticide dusting of persons at risk (lice), dusting of rat burrows (fleas), treatment of dogs carrying ticks, or appropriate measures to reduce mite populations. Repellants are also useful against ticks and mites.