The Biological Characteristics and Mouse Model of Lassa Virus From the First Imported Case in China.

Lassa fever (LF) is a fatal hemorrhagic disease caused by the Lassa virus (LASV), which mainly spreads in Africa. As China's interactions with Africa become more frequent, the risk of LF being imported into China also rises, making the study of LASV increasingly urgent. In this study, the Lineage IV LASV strain was successfully isolated from the first imported case in China. Compared with the LASV genome, the isolated strain may exhibit greater infectivity and interspecies transmission capabilities. We successfully established BALB/c, C57BL/6, and AG129 mouse infection models and found that intranasal inoculation was the most stable infection method. Select the anti-LASV drug LHF-535 for preliminary evaluation, further confirming the stability of the model. In summary, the isolated strain exhibits enhanced transmission capabilities and may spread between mice via the respiratory tract, meriting greater attention and emphasis. This study will bridge the gap in China's independent P4-level pathogen isolation, meet national biosafety and strategic needs, and provide certain support for LASV research.