目的

 探讨被病原体污染的器物和环境可否认定为传染源，分析新型冠状病毒“物传人”的理论基础。方法 分析中、西方学术界对传染源定义的差异，回顾甲型肝炎、禽流感，重症急性呼吸综合征(SARS)等多种病毒性传染病“环境传人”和“物传人”的实例，运用生命科学的基本理论、基础知识，分析我国新型冠状病毒感染防控工作遇到的“进口冷链”“边贸或口岸作业”“国际邮件”等多种渠道传播新型冠状病毒的案例。

结果

 阐明我国对传染源定义严谨，强调可增殖性，只认可被病原体感染的人和动物为传染源；而西方的定义较宽泛，强调传染性，被病原体污染的器物和环境也可认定为传染源。通过理论分析和多方面实例证实新型冠状病毒在常温环境中存活期较长可至数天，在低温冷冻条件下存活期可延长至数月，被新型冠状病毒污染的器物可以引发间接接触感染，只是这种“物传人”的概率相对较低。

结论

 我国的传染源定义严谨、科学、实用，已在传染病防治工作中形成惯例，不宜改动。随着核酸检测技术的普及，新型冠状病毒感染等病毒性传染病筛查的目标可以从“快查传染源”转变为“快查病毒来源”,包括环境中的病毒。了解新型冠状病毒“物传人”理论基础，就理解了坚持“人物同防”等积极策略的必要性。

Objective

 To explore whether objects and environment contaminated by pathogens can be identified as infection sources, and to analyze the theoretical basis of “object-to-human transmission” for SARS-CoV-2.

Methods

 Differences in the definition of infection sources between Chinese and Western academics are analyzed. Examples of “environment-to-human transmission” and “object-to-human transmission” for viral infectious diseases such as hepatitis A, avian influenza and severe acute respiratory syndrome (SARS) were reviewed. The basic theory and know-ledge of life science were applied to analyze various cases of SARS-CoV-2 transmission via multiple channels such as “imported cold chain” “border trade or port operation” “international mail”, etc. encountered in SARS-CoV-2 infection prevention and control effort of China.

Results

 It is clarified that the definition about infection sources in China is rigorous, emphasizing the proliferation, and only human and animal infected by pathogens can be recognized as infection source, while the Western definitions are broader, emphasizing infectivity, objects and environment contaminated by pathogens can also be identified as infection source. Through theoretical analysis and various examples, it is confirmed that SARS-CoV-2 can survive in normal temperature environment for several days, extends to several months under cryogenic condition. The objects contaminated by SARS-CoV-2 can cause indirect contact infection. However, the probability of “object-to-human transmission” is relatively lower. Conclusion Definitions about infection sources in China is rigorous, scientific, and practical, and has formed a convention in the prevention and control of infectious diseases. Therefore, there is no need to amend the definition. With popularizing nucleic acid test, the goal of screening for viral infectious diseases such as COVID-19 can be converted from “quickly finding sources of infection” to “quickly seeking sources of the virus”, including viruses in environment. Understanding the theoretical basis of “object-to-human transmission”, the necessity of positive strategies such as “preventing the transmission from both sources of human and objects” would be fully comprehended.