Abstract
BackgroundYanbian is located at the junction between China, Russia, and North Korea. We aimed to determine the species distribution and pathogens carried by ticks in Yanbian.MethodsA total of 2673 unattached ticks were collected from eight counties and cities in Yanbian and classified morphologically. Candidatus Rickettsia tarasevichiae (CRT), spotted fever group Rickettsia (SFGR), severe fever thrombocytopenia syndrome virus (SFTSV), Theileria, and other pathogens were detected using polymerase chain reaction (PCR) and real-time quantitative polymerase chain reaction followed by phylogenetic and genotypic analyses.ResultsAccording to the morphological classification, the main tick species in Yanbian were Haemaphysalis longicornis, Ixodes persulcatus, Dermacentor silvarum, Haemaphysalis japonica, and Haemaphysalis concinna. Candidatus Rickettsia tarasevichiae, spotted fever group Rickettsia, severe fever thrombocytopenia syndrome virus, and Theileria orientalis were detected in H. longicornis, Candidatus Rickettsia tarasevichiae, spotted fever group Rickettsia, and severe fever thrombocytopenia syndrome virus were detected in I. persulcatus, H. japonica, and D. silvarum, but only severe fever thrombocytopenia syndrome virus was detected in H. concinna. Mixed infection with Candidatus Rickettsia tarasevichiae and severe fever thrombocytopenia syndrome virus was found in I. persulcatus and H. japonica. The gene sequences of all tested pathogens exhibited 95.7%–100% homology with sequences registered in GenBank. Phylogenetic analysis showed that different spotted fever group Rickettsia and severe fever thrombocytopenia syndrome virus genotypes were closely related to the Korean strains. We provide the first evidence for the presence of the spotted fever group Rickettsia genotypes of Candidatus Rickettsia longicornii, ompA, ompB, sca4, and rrs, in Haemaphysalis longicornis in Yanbian. ConclusionsThese results provide epidemiological data to support the prevention and control of ticks and tick-borne diseases in the border areas of China, North Korea, and Russia.
Isolation of spotted fever group rickettsiae from Ixodes persulcatus ticks in the central part of Hokkaido, Japan