Mediterranean spotted fever in Algeria — new trends

Abstract

Mediterranean spotted fever (MSF) due to Rickettsia conorii is the most important tick-borne disease occurring in North Africa. However, there are only a few fragmentary reports on the epidemiology and clinical aspects of rickettsioses in North Africa, and cases are still rarely documented. We report herein a prospective study conducted in Oran, the second largest city in Algeria. This disease has not been properly described in Oran or in other Algerian cities. A total of 167 cases of Mediterranean spotted fever were documented for the first time by the use of reference methods including immunofluorescence serology and Western blot and absorption studies, including isolation in culture by the shell-vial techniques, and molecular tools. Although some aspects of MSF were found to be in accordance with the general epidemiology of the disease, uncommon aspects were found, including increased incidence and the presence of multiple inoculation eschars in 12% of patients. The role of climatic changes in alterations of host-seeking and feeding behaviors of the vectors, including the brown dog tick Rhipicephalus sanguineus, is discussed. Also, 49% of patients were hospitalized with a severe form. The global death rate was 3.6%, but it was 54.5% in patients hospitalized with major neurological manifestations and multiorgan involvement. The present report gives a unique panel of clinical aspects of MSF as well as new trends in this disease. Entomological, climatic, and molecular studies are needed to better understand both epidemiological and clinical aspects of MSF.