LETTERS

felis (7). The serologic findings indi-cated antibodies at a higher level to R. aeschlimannii than to other tested spe-cies. R. aeschlimannii is phylogeneti-cally distant from R. conorii but is closely related to R. rhipicephali and R. montanensis, which have never been described as human pathogens. This patient appeared to have a typical case of R. conorii infection, with sea-sonal and geographic characteristics favoring this diagnosis (3). This case was clinically and epidemiologically mistaken for R. conorii infection, sug-gesting that R. aeschlimanii may be another cause of Mediterranean spot-ted fever in Morocco. The systematic identification of rickettsial species in human infections continues to increase the number of recognized human pathogens (3). This finding has demonstrated once again that more than one species or serotype of tick-transmitted rickettsia may be prevalent in the same area, as observed, for example, with R. slo-vaca, “R. mongolotimonae, ” and R. conorii in southern France (3); R. afri-cae and R. conorii in sub-Saharan Africa (8); and R. conorii and Israeli spotted fever rickettsia in Sicily and Portugal (9). Rickettsia species first identified in ticks should be consid-ered as potential human pathogens, as all recently described tick-transmitted rickettsiae pathogenic for humans were initially found in ticks and were considered nonpathogenic for several years (3)