The coronavirus disease 2019 (COVID-19) and concerns about several other pandemics in the 21st century have attracted extensive global attention. These emerging infectious diseases threaten global public health and raise urgent studies on unraveling the underlying mechanisms of their transmission from animals to humans. Although numerous works have intensively discussed the cross-species and endemic barriers to the occurrence and spread of emerging infectious diseases, both types of barriers play synergistic roles in wildlife habitats. Thus far, there is still a lack of a complete understanding of viral diffusion, migration, and transmission in ecosystems from a macro perspective. In this review, we conceptualize the ecological barrier that represents the combined effects of cross-species and endemic barriers for either the natural or intermediate hosts of viruses. We comprehensively discuss the key influential factors affecting the ecological barrier against viral transmission from virus hosts in their natural habitats into human society, including transmission routes, contact probability, contact frequency, and viral characteristics. Considering the significant impacts of human activities and global industrialization on the strength of the ecological barrier, ecological barrier deterioration driven by human activities is critically analyzed for potential mechanisms. Global climate change can trigger and expand the range of emerging infectious diseases, and human disturbances promote higher contact frequency and greater transmission possibility. In addition, globalization drives more transmission routes and produces new high-risk regions in city areas. This review aims to provide a new concept for and comprehensive evidence of the ecological barrier blocking the transmission and spread of emerging infectious diseases. It also offers new insights into potential strategies to protect the ecological barrier and reduce the wide-ranging risks of emerging infectious diseases to public health.

2019 年冠状病毒病 (COVID-19) 以及对 21 世纪其他几种流行病的担忧引起了全球的广泛关注。这些新出现的传染病威胁着全球公共卫生，并引发了迫切的研究，以揭示其从动物传播到人类的潜在机制。尽管许多著作深入讨论了新兴传染病发生和传播的跨物种和地方性障碍，但这两种类型的障碍在野生动物栖息地中发挥着协同作用。迄今为止，人们仍然缺乏从宏观角度对病毒在生态系统中扩散、迁移和传播的完整认识。在这篇综述中，我们概念化了生态屏障，它代表了病毒自然宿主或中间宿主的跨物种和地方性屏障的综合影响。我们全面讨论了影响病毒从自然栖息地的宿主向人类社会传播的生态屏障的关键影响因素，包括传播途径、接触概率、接触频率和病毒特征。考虑到人类活动和全球工业化对生态屏障强度的重大影响，对人类活动驱动的生态屏障恶化的潜在机制进行了批判性分析。全球气候变化可以引发并扩大新发传染病的范围，而人类干扰则促进了更高的接触频率和更大的传播可能性。此外，全球化推动了更多的传播路线，并在城市地区产生了新的高风险区域。 本综述旨在为阻断新发传染病传播和扩散的生态屏障提供新概念和全面证据。它还为保护生态屏障和减少新发传染病对公共卫生造成的广泛风险的潜在策略提供了新的见解。