[Microorganism "Montezuma" of the order Rickettsiales: the potential causative agent of tick-borne disease in the Far East of Russia].

A new microorganism, tentatively named "Montezuma" was detected in ticks and in specimens (blood, bioptic specimens of the primary affect) taken from patients with an acute fever disease, etiologically linked with the bites of Ixodes ticks in the Far East of the Russian Federation. After sequencing the products of the amplification of DNA isolated from ticks with wide-spectrum primers new primers were developed, highly specific to the unusual sequence thus obtained. The study revealed that ticks of the species Ixodes persulcatus (97%) and Haemophysalis concinnae (5%) contained DNA of this microorganism. The same DNA was detected in materials taken from the patients. The phylogenetic analysis of the gene showed that this organism formed an independent and well defined branch within the order Rickettsiales. The nearest homology (89%) was observed with recently detected endosymbiotes Acanthamoeba. The similarity with their relatives from the families Rickettsiaceae and Anaplasmataceae of the order Rickettsiales was within 81-86%, which made it possible to infer the existence of, probably, only a new genus, but also a family. The isolated DNA belonged, supposedly, to the new microoganism which caused a tick-borne disease in humans, transmitted through bites of Ixodes ticks, and was, supposedly, widely spread in the southern area of the Khabarovsk Territory.