| Abstrakt: |
In order to understand the natural situation of rickettsiae in the ticks in Japan, the rickettsial genes, gltA gene, rOmpA gene, and 17‐kDa gene, were amplified from the ticks by nested PCR. The prevalences of rickettsial gltA genes among Haemaphysalis formosensis, H. longicornis, H. megaspinosa, Ixodes ovatus, H. flava, H. kitaokai, and I. persulcatuswere 62, 57, 24, 24, 19, 13, and 10%, respectively; 26% (186/722) being the average. The gltA genes amplified from the ticks were classified into 9 genotypes (I to IX) by the difference in nucleotide sequences. Genotype I was detected from 7 species of ticks. Genotype II mainly was detected from H. longicornisand H. formosensis. Genotypes III and VII mainly were detected from H. flavaand I. ovatus. The polarization in the distribution of genotypes among regions where the ticks were collected was not clear. Based on the phylogenetic analysis of the three genes presented here, genotypes I, III, and IV (detected from H. formosensis, H. hystricia, and I. ovatus) are genetically close with each other, but rickettsiae of the same property still have not been isolated from ticks anywhere in the world. These genotypes should be considered as new species among SFG rickettsiae. Genotype II was identical with strain FUJ‐98, genetically close to R. japonicawhich has been isolated from ticks in China. Genotype V was identical with R. felisand strain California 2 isolated from the cat flea. This is the first report on the detection of R. felisfrom ticks. Genotype VI detected from Ixodessp. did not seem to belong to genus Rickettsia. Based on the previous antigenic data and the phylogenetic analysis presented here, Genotype VII should be considered a variant of R. helveticaand genotype VIII detected from I. ovatusand I. persulcatuswere identical with R. helvetica. Genotype IX detected from I. nipponensiswas genetically close to the strains IRS3, IRS4, and IrR/Munich isolated from I. ricinusin Slovakia and German. |
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