Isolation of a novel rickettsia from the tick Dermacentor silvarum in Baikal lake region

A new species of rickettsiae with unknown pathogenicity has been detected in ticks Dermacentor silvarum in the region of Baikal Lake. As revealed by the analysis of the primary structure of the gene fragment coding surface membrane protein of 190 kD (rOmpA), the nucleotide sequence of the rickettsiae under study is mostly similar to the sequences of R. sp. MOAa isolate (96%), R. sp. WB-8-2 (96%), R. massiliae strain GS (94%), Rickettsia BAR-29 (94%), R. rhipicephali (94%). Similarity with the sequence of R. sibirica has proved to be 91%. The data thus obtained indicate that the detected rickettsiae represent a new rickettsial species in the territory of East Siberia.