The novel coronavirus disease (COVID-19) outbreak that emerged at the end of 2019 has now swept the world for more than 2 years, causing immeasurable damage to the lives and economies of the world. It has drawn so much attention to discovering how the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) originated and entered the human body. The current argument revolves around two contradictory theories: a scenario of laboratory spillover events and human contact with zoonotic diseases. Here, we reviewed the transmission, pathogenesis, possible hosts, as well as the genome and protein structure of SARS-CoV-2, which play key roles in the COVID-19 pandemic. We believe the coronavirus was originally transmitted to human by animals rather than by a laboratory leak. However, there still needs more investigations to determine the source of the pandemic. Understanding how COVID-19 emerged is vital to developing global strategies for mitigating future outbreaks.

中文翻译：

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COVID-19 大流行的起源：简要概述

2019年底爆发的新型冠状病毒肺炎（COVID-19）疫情，至今已席卷全球2年多，对世界人民的生命和经济造成了不可估量的损失。发现严重急性呼吸系统综合症冠状病毒 2 (SARS-CoV-2) 是如何起源和进入人体的，引起了广泛关注。目前的争论围绕着两个相互矛盾的理论展开：实验室溢出事件和人类接触人畜共患疾病的情景。在此，我们回顾了在 COVID-19 大流行中发挥关键作用的 SARS-CoV-2 的传播途径、发病机制、可能宿主以及基因组和蛋白质结构。我们认为冠状病毒最初是由动物传播给人类的，而不是通过实验室泄漏传播给人类的。然而，仍然需要更多的调查来确定大流行病的来源。了解 COVID-19 的出现方式对于制定减轻未来疫情爆发的全球战略至关重要。