Susceptibility of tree shrew to SARS-CoV-2 infection

Yuan Zhao,Jiansheng Liu,Jingwen Xu,Dexuan Kuang,Shuaiyao Lu,Yun Yang,Daoju Wu,Haiting Long,Jingmei Li,Jing Yang,Chang–Jin Ma ,Jian Gao ,Kan Ding ,Yu Wu ,Shuaiyang Zhao ,Yinqiu Zheng,Hongqi Liu,Mengli Yang,Haixuan Wang,Haiyan Li,Junbin Wang,Xiaozhong Peng

doi:10.1038/s41598-020-72563-w

Abstract

Since severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) became a pandemic event in the world, it has not only caused huge economic losses, but also a serious threat to global public health. Many scientific questions about SARS-CoV-2 and Coronavirus disease (COVID-19) were raised and urgently need to be answered, including the susceptibility of animals to SARS-CoV-2 infection. Here we tested whether tree shrew, an emerging experimental animal domesticated from wild animal, is susceptible to SARS-CoV-2 infection. No clinical signs were observed in SARS-CoV-2 inoculated tree shrews during this experiment except the increasing body temperature particularly in female animals. Low levels of virus shedding and replication in tissues occurred in all three age groups. Notably, young tree shrews (6 months to 12 months) showed virus shedding at the earlier stage of infection than adult (2 years to 4 years) and old (5 years to 7 years) animals that had longer duration of virus shedding comparatively. Histopathological examine revealed that pulmonary abnormalities were the main changes but mild although slight lesions were also observed in other tissues. In summary, tree shrew is less susceptible to SARS-CoV-2 infection compared with the reported animal models and may not be a suitable animal for COVID-19 related researches. However, tree shrew may be a potential intermediate host of SARS-CoV-2 as an asymptomatic carrier.

Highlights

Since severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) became a pandemic event in the world, it has caused huge economic losses, and a serious threat to global public health
The infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is known as Coronavirus disease (COVID-19)
Very low levels of Angiotensin-converting enzyme 2 (ACE2) were found in the tissues from the adult tree shrews (Table S2). These results indicated that SARS-CoV-2 could replicate in multiple tissues of tree shrews to a certain extend and the ACE2-independent mechanism underlying SARS-CoV-2 infection may exist in tree shrews

Summary

Introduction

Since severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) became a pandemic event in the world, it has caused huge economic losses, and a serious threat to global public health. We tested whether tree shrew, an emerging experimental animal domesticated from wild animal, is susceptible to SARS-CoV-2 infection. Tree shrew is less susceptible to SARS-CoV-2 infection compared with the reported animal models and may not be a suitable animal for COVID-19 related researches. There are still some critical aspects that need to be further investigated in COVID-19 patients, such as cytokine storm, immunopathogenic damages, tropism of SARS-CoV-2, and other sources of SARS-CoV-2 infection besides bat and pangolin that are regarded as the origin of SARS-CoV-22–4 From these points of view, studies of animals become essentially important. The findings in the present study suggested that tree shrew may not be a suitable model of COVID-19 but a potential intermediate host of SARS-CoV-2

Methods

Results

Conclusion