Abstract: A double polymerase chain reaction,using nested primers of M genome segmant of Hantaan virus,was established and applied to detect the viral RNA extracted from the experimental mites and mice by a single step of acid guanidinium thiocyanate-phenol-chloroform.The results were showed in agarosegel electrophoresis and dot-blot hybridization by digoxigenin enzyme linked immunosorbent assay system.The virus was detected in lungs of mice at the 9th day post-inoculation of the tissue suspension of the mites infected with Hantaan virus,and in the mites at 10 and 30 days post infection.No virus was detected from mites with Seoul strain infection.This indicated that the nested RT-PCR can be used as a simple,sensitive,specific method with in situ hybridization for study of transmission of HFRSV by gamasid mites.