PUBLIC HEALTH CONCERN
Several of the Rickettsia species encountered in Europe, together with A. phagocytophilum, have been associated with human infections. Cases of R. aeschlimannii have been reported in North Africa, where the bacterium is more prevalent than in Europe.
Rickettsia akari, the causative agent of rickettsialpox, and R. conorii, the agent of Mediterranean spotted fever, are both well-established human pathogens. Rickettsiafelis is an emerging pathogen; human cases are being reported with increasing frequency across Europe and elsewhere in the world. Rickettsia helvetica has recently been associated with a case of meningitis in Sweden. Rickettsia massiliae infections have been reported in Italy and southern France, R. raoultii and R. slovaca are associated with tick- borne lymphadenopathy, another emerging human infection that is probably present across much of Europe. Finally, about a dozen human cases of R. sibirica infection have also appeared, to date, in the literature. The one TG species present in Europe, R. typhi, is also a well-established human pathogen, causing murine typhus. Typically, the clinical symptoms of SFG rickettsioses include fever, headache, muscle pain, rash, local lymphadenopathy and a characteristic inoculation eschar (sometimes referred to as a ‘tache noire’ ) at the site of the arthropod bite.Anaplasma phagocytophilum infection in humans, referred to as human granulocytic anaplasmosis, is currently far more frequently recognized in the USA than Europe, where the incidence is second only to that of B. burgdorferi infection. However, human infections have been reported in various parts of Europe, and in several countries serological surveys have suggested significant levels of exposure to the bacterium. Human granulocytic anaplasmosis typically presents non-specifically, with fever, headache, myalgia, malaise, thrombocytopenia and leucopenia among the most common symptoms.