Rickettsia raoultii, the predominant Rickettsia found in Dermacentor silvarum ticks in China-Russia border areas.

Since the year 2000, clinical patterns resembling tick-borne rickettsioses have been noticed in China-Russia border areas. Epidemiological data regarding species of the aetiological agent, tick vector prevalence and distribution as well as incidence of human cases in the areas are still sparse to date. In order to identify Rickettsia species occurring in the areas, we investigated Dermacentor silvarum collected in the selected areas. Rickettsia raoultii was the predominant Rickettsia found in D. silvarum evident with ompA, ompB, gltA and 17 kDa protein genes. The Rickettsia prevalence in D. silvarum appeared to be 32.25 % with no sex difference. The results extend the common knowledge about the geographic distribution of R. raoultii and its candidate vector tick species, which suggest an emerged potential threat of human health in the areas.