[Detection of north-Asia tick-borne spotted fever in ticks and rodents along the Heilongjiang river-side by restriction fragment length polymorphism of PCR products].

In order to elucidate the natural foci of North-Asia tick-borne spotted fever along the bank of Heilongjiang river, we used PCR/RFLP to detect spotted fever group rickettsiae in ticks and rodents. The results showed that the wild samples of Dermacentor silvarum, Haemaphysalis concinna and Apodemus agrarius, Microtus fortis, Clethrionomys rufocanus and Ondatra zibethica were all positive with amplification, but typhus rickettsiae, tsutsugamushi fever rickettsiae and Q fever rickettsiae were all negative. Futher RFLP analysis of amplified products with PstI and Rsal demonstrated that their restriction endonuclease profiles were identical to Rickettsia sibirica, but were different from the other prototype strains of SFG rickettsiae, suggesting the possible existance of natural foci of North-Asia tick borne spotted fever in these areas.