New evidence on tick-borne rickettsioses in the Altai region of Russia using primary lesions, serum and blood clots of molecular and serological study.

Tick-borne rickettsioses (TBRs) have similar clinical symptoms and can give serological cross-reaction. We firstly found that in the natural foci of North Asian tick typhus (NATT) in the Altai region of Russia, TBRs can be caused by two Rickettsia species: Rickettsia sibirica subsp. sibirica (causative agent of NATT) and Rickettsia heilongjiangensis. Rickettsial DNA was detected in primary lesions, serum samples and blood clots using real-time PCR. Therefore, each case of TBRs should be verified by using molecular typing. TBR caused by R. sibirica subsp. sibirica - NATT dominates on the territory of Altai region.