Small mammals in a biodiversity hotspot harbor viruses of emergence risk

Metagenomic sequencing has transformed the understanding of viral diversity in wildlife and the potential threats these viruses pose to human health. Despite this progress, such sequencing studies often have lacked systematic and ecologically informed sampling, thereby likely missing many potential human pathogens and the drivers behind their ecology, evolution and emergence. We conducted an extensive search for viruses in the lungs, spleens and guts of 1688 mammals from 38 species across 428 sites in Yunnan Province, China-a hotspot for zoonoses emergence. We identified 162 mammalian viruses, including 102 new ones and 24 posing potential risks to humans due to their relationships with known human pathogens associated with serious diseases or their ability to cross major host species barriers. Our findings offer an in-depth view of virus organotropism, cross-host associations, host sharing patterns, and the ecological factors influencing viral evolution, all of which are critical for anticipating and mitigating future zoonotic outbreaks.