冠状病毒感染有相对严格的宿主和组织特异性，其中部分病毒演化中会发生细胞嗜性改变。冠状病毒的跨宿主感染能力主要取决于病毒表面棘突蛋白的变异及其与受体相互作用的特异性改变。棘突蛋白的变异主要集中在受体结合域（RBD），其他区域也与病毒感染的宿主细胞特异性有关。另外，较大的RNA基因组、独特的套氏亚基因组转录、复制过程中模板转换引起的高频率基因重组等使冠状病毒不断出现毒力或宿主变异，而共感染和持续性感染则为病毒重组及跨宿主感染提供了机会。

Coronaviruses generally infect their natural hosts but scarcely infect other species of animals. The interspecies transmission of coronaviruses depends on the interaction of spike protein with the receptor. Receptor binding domains as well as other domains in spike proteins are mainly related to the tropism of coronaviruses. The emergence of new and host-across strains of coronaviruses is due to the huge RNA genome, specific subgenomic RNAs and high recombinant rate between RNAs. And both persist infection and co-infection provided the opportunities for the recombinant events and sequential host-shifting.