Oral SARS-CoV-2 Inoculation Establishes Subclinical Respiratory Infection with Virus Shedding in Golden Syrian Hamsters
Andrew Chak-Yiu Lee, 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 Chan, Kelvin Kai‐Wang To, Shuofeng Yuan, Jie Zhou, Hin Chu, Kwok‐Yung Yuen
Abstract
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.