COVID-19-like symptoms observed in Chinese tree shrews infected with SARS-CoV-2
Ling Xu, 中国科学院昆明动物研究所，动物模型与人类疾病机理重点实验室，KIZ-CUHK生物资源与疾病分子机理联合实验室，云南 昆明 650223，中国, Dandan Yu, Yuhua Ma, Yulin Yao, Rong‐Hua Luo, Xiaoli Feng, Hourong Cai, Jian-Bao Han, Xuehui Wang, Minghua Li, Changwen Ke, Yong‐Tang Zheng, Yong‐Gang Yao, 中国科学院昆明动物研究所，国家昆明高等级生物安全灵长类动物实验中心，生物安全大科学研究中心，云南，昆明 650223，中国, 中国科学院昆明动物研究所，国家非人灵长类实验动物资源库，模式动物表型与遗传研究国家重大科技基础设施（灵长类设施），云南 昆明， 650223，中国, 中国科学院大学昆明生命科学学院，云南 昆明 650204，中国, 南京大学附属鼓楼医院，呼吸与危重症医学科，江苏 南京 210008，中国, 广东省疾病预防控制中心，应急病原学检测重点实验室，广东 广州 510440，中国, 中国科学院脑科学与智能技术卓越创新中心，上海 200031，中国
Abstract
The coronavirus disease 2019 (COVID-19) pandemic continues to pose a global threat to the human population. Identifying animal species susceptible to infection with the SARS-CoV-2/ HCoV-19 pathogen is essential for controlling the outbreak and for testing valid prophylactics or therapeutics based on animal model studies. Here, different aged Chinese tree shrews (adult group, 1 year old; old group, 5-6 years old), which are close relatives to primates, were infected with SARS-CoV-2. X-ray, viral shedding, laboratory, and histological analyses were performed on different days post-inoculation (dpi). Results showed that Chinese tree shrews could be infected by SARS-CoV-2. Lung infiltrates were visible in X-ray radiographs in most infected animals. Viral RNA was consistently detected in lung tissues from infected animals at 3, 5, and 7 dpi, along with alterations in related parameters from routine blood tests and serum biochemistry, including increased levels of aspartate aminotransferase (AST) and blood urea nitrogen (BUN). Histological analysis of lung tissues from animals at 3 dpi (adult group) and 7 dpi (old group) showed thickened alveolar septa and interstitial hemorrhage. Several differences were found between the two different aged groups in regard to viral shedding peak. Our results indicate that Chinese tree shrews have the potential to be used as animal models for SARS-CoV-2 infection.