Oral SARS-CoV-2 Inoculation Establishes Subclinical Respiratory Infection with Virus Shedding in Golden Syrian Hamsters
49 Pages Posted: 10 Aug 2020 Publication Status: Published
More...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 faeces of patients, evidence supporting oral acquisition of SARS-CoV-2 is unavailable. Utilizing Syrian hamster model, we demonstrated that the severity of pneumonia induced by intranasal inhalation of SARS-CoV-2 increased with virus inoculum. SARS-CoV-2 retained its infectivity in vitro in simulated human fed-gastric and fasted-intestinal fluid after two hours. Oral inoculation with the highest intranasal inoculum (10 5 PFU) caused only mild pneumonia in 67% (4/6) of the animals with no clinical symptoms. The lung histopathology and viral load were significantly lower than those infected by the lowest intranasal inoculum (100 PFU). However, 83% oral infection (10/12 hamsters) had similar level of detectable viral shedding from oral swabs and faeces as intranasally infected hamsters. Our findings indicated oral acquisition of SARS-CoV-2 can establish asymptomatic respiratory infection with less efficiency.
Note: Funding: This study was partly supported by the donations of May Tam Mak Mei Yin, Richard Yu and Carol Yu, the Shaw Foundation Hong Kong, Michael Seak-Kan Tong, Respiratory Viral Research Foundation Limited, Lo Ying Shek Chi Wai Foundation, Hui Ming, Hui Hoy and Chow Sin Lan Charity Fund Limited, Chan Yin Chuen Memorial Charitable Foundation, Marina Man-Wai Lee, the Hong Kong Hainan Commercial Association South China Microbiology Research Fund, the Jessie & George Ho Charitable Foundation, Perfect Shape Medical Limited, Kai Chong Tong, and Foo Oi Foundation Limited; and funding from the Health and Medical Research Fund (grant no. COVID190121 and COVID190123), the Food and Health Bureau, The Government of the Hong Kong Special Administrative Region; the National Program on Key Research Project of China (grant no. 2020YFA0707500 and 2020YFA0707504); the Consultancy Service for Enhancing Laboratory Surveillance of Emerging Infectious Diseases and Research Capability on Antimicrobial Resistance for Department of Health of the Hong Kong Special Administrative Region Government; and the Theme-Based Research Scheme (T11/707/15) of the Research Grants Council, Hong Kong Special Administrative Region. The funding sources had no role in the study design, data collection, analysis, interpretation, or writing of the report.
Declaration of Interest: None to declare
Keywords: coronavirus, COVID-19, SARS-CoV-2, hamster, oral, gastrointestinal, asymptomatic
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