Oral SARS-CoV-2 Inoculation Establishes Subclinical Respiratory Infection with Virus Shedding in Golden Syrian Hamsters

• Main Authors: Andrew Chak-Yiu Lee, Anna Jinxia Zhang, Jasper Fuk-Woo Chan, Can Li, Zhimeng Fan, Feifei Liu, Yanxia Chen, Ronghui Liang, Siddharth Sridhar, Jian-Piao Cai, Vincent Kwok-Man Poon, Chris Chung-Sing Chan, Kelvin Kai-Wang To, Shuofeng Yuan, Jie Zhou, Hin Chu, Kwok-Yung Yuen
• Format: Article
• Language: English
• Published: Elsevier 2020-10-01
• Series: Cell Reports Medicine
• Subjects: coronavirus; COVID-19; SARS-CoV-2; hamster; oral; gastrointestinal
• Online Access: http://www.sciencedirect.com/science/article/pii/S2666379120301634

Summary: Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is transmitted largely by respiratory droplets or airborne aerosols. Despite being frequently found in the immediate environment and feces of patients, evidence supporting the oral acquisition of SARS-CoV-2 is unavailable. Using the Syrian hamster model, we demonstrate that the severity of pneumonia induced by the intranasal inhalation of SARS-CoV-2 increases with virus inoculum. SARS-CoV-2 retains its infectivity in vitro in simulated human-fed-gastric and fasted-intestinal fluid after 2 h. Oral inoculation with the highest intranasal inoculum (105 PFUs) causes mild pneumonia in 67% (4/6) of the animals, with no weight loss. The lung histopathology score and viral load are significantly lower than those infected by the lowest intranasal inoculum (100 PFUs). However, 83% of the oral infections (10/12 hamsters) have a level of detectable viral shedding from oral swabs and feces similar to that of intranasally infected hamsters. Our findings indicate that the oral acquisition of SARS-CoV-2 can establish subclinical respiratory infection with less efficiency.