Molecular phylogenic study of Ehrlichia spp. microorganisms as the etiological agents of emerging diseases in Japan

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1)Ehrlichial gene was detected from small rodents trapped in a Lyme disease-endemic area in Hokkaido, the northernmost island of Japan. Primer pairs of 168 rDNA targeting the genus of Ehrlichia and other region of the 16S rDNA specific for E. chaffeensis and E. muris were used for identification. The DNA fragment specific for 16S rDNA of E. spp. was detected from 4 of 94 Apodemus. speciosus mice (positive rate 4.3%) and 5 of 73 Clethrionomys rufocanus bedfordiae mice (positive rate 6.8%). The nucleotide sequence of the amplified 168 rDNA fragment was most similar to those of E muris-like ehrlichia, E spp HF565 and Shizuoka-36 originating in the northeastern part of Japan. In phylogenic analysis based on 16S rDNA sequences, these northeastern and southwestern groups of E. murrslike ehrlichia made a cluster with E. muris group microorganisms. These results suggest that there are two groups of E. murislike microorganisms in Japan.2)A novel genotype of Ehrlichia rummantium, the causative agent of heartwater, was genetically detected in the Sudan. The new genotype was provisionally named as "Gedaref". The results of phylogenic analyses on the regions of pCS20 and major antigen protein I (map)) genes revealed that the ehrlichia) strain belongs to E. ruminantium-group, but does not correspond with any known strains of E. ruminantium. Furthermore, as the results of phylogenic analyses on map), "Gedaref" made clusters with several strains of E. ruminantium other than Um Banein, which had been known as the sole strain of E. ruminantium in the Sudan. This work provided the evidence that not only Um Banein strain but also the other strain exist in the Sudan.