Abstract: "SCID mice were intraperitoneally inoculated with a mixture of MHV1 ,MHV3，A59，JHM. The blood ,liver,lung，brain and spleen samples were taken, 50mg of liver，lung and brain samples »and 15mg of spleen sample were homogenized respectively with a plastic homogenizer in a 1. 5ml microtube for extracting total RNA from the tissues. Then, total RNA was reversely transcribed into cDNA, and the cDNA was amplified by PCR. The results indicated that MHV in blood,liver and spleen was detected 1 day after the inoculation,then in lung and in brain on 2 and 5 days after the inoculation ,respectively,and MHV replicated mainly in liver. "

Key words: Mouse hepatitis virus, SCID mouse, RT-PCR