Investigation of Borrelia spp. in ticks (Acari: Ixodidae) at the border crossings between China and Russia in Heilongjiang Province, China.

OBJECTIVE To investigate the precise species of tick vector and the Borrelia spirochete pathogen at the Heilongjiang Province international border with Russia. METHODS In this study, ticks were collected from 12 Heilongjiang border crossings (including grasslands, shrublands, forests, and plantantions) to determine the rate and species type of spirochete-infected ticks and the most prevalent spirochete genotypes. RESULTS The ticks represented three genera and four species of the Ixodidae family [Ixodes persulcatus, Dermacentor silvarum, Haemaphysalis concinna and Haemaphysalis japonica]. Ixodes persulcatus had the highest amount of Borrelia burgdorferi sensu lato infection of 25.6% and the most common species of Borrelia isolated from Ixodes persulcatus was Borrelia garinii, strain PD91. CONCLUSIONS Our results suggest that Borrelia garinii PD91-infected Ixodes persulcatus may be the principal cause of Lyme disease in the border crossing areas of Heilongjiang Province.