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

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.

Lee AC ，Zhang AJ ，Chan JF ，Li C ，Fan Z ，Liu F ，Chen Y ，Liang R ，Sridhar S ，Cai JP ，Poon VK ，Chan CC ，To KK ，Yuan S ，Zhou J ，Chu H ，Yuen KY ... -  《-》

Sex Differences in Lung Imaging and SARS-CoV-2 Antibody Responses in a COVID-19 Golden Syrian Hamster Model.

Dhakal S ，Ruiz-Bedoya CA ，Zhou R ，Creisher PS ，Villano JS ，Littlefield K ，Ruelas Castillo J ，Marinho P ，Jedlicka AE ，Ordonez AA ，Bahr M ，Majewska N ，Betenbaugh MJ ，Flavahan K ，Mueller ARL ，Looney MM ，Quijada D ，Mota F ，Beck SE ，Brockhurst J ，Braxton AM ，Castell N ，Stover M ，D'Alessio FR ，Metcalf Pate KA ，Karakousis PC ，Mankowski JL ，Pekosz A ，Jain SK ，Klein SL ，Johns Hopkins COVID-19 Hamster Study Group ... -  《mBio》

Dynamic Changes of the Blood Chemistry in Syrian Hamsters Post-Acute COVID-19.

Hsu CJ ，Lin WC ，Chou YC ，Yang CM ，Wu HL ，Cheng YH ，Liu PC ，Chang JY ，Chen HY ，Sun JR ... -  《Microbiology Spectrum》

Persimmon-derived tannin has antiviral effects and reduces the severity of infection and transmission of SARS-CoV-2 in a Syrian hamster model.

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread across the world. Inactivating the virus in saliva and the oral cavity represents a reasonable approach to prevent human-to-human transmission because the virus is easily transmitted through oral routes by dispersed saliva. Persimmon-derived tannin is a condensed type of tannin that has strong antioxidant and antimicrobial activity. In this study, we investigated the antiviral effects of persimmon-derived tannin against SARS-CoV-2 in both in vitro and in vivo models. We found that persimmon-derived tannin suppressed SARS-CoV-2 titers measured by plaque assay in vitro in a dose- and time-dependent manner. We then created a Syrian hamster model by inoculating SARS-CoV-2 into hamsters' mouths. Oral administration of persimmon-derived tannin dissolved in carboxymethyl cellulose before virus inoculation dramatically reduced the severity of pneumonia with lower virus titers compared with a control group inoculated with carboxymethyl cellulose alone. In addition, pre-administration of tannin to uninfected hamsters reduced hamster-to-hamster transmission of SARS-CoV-2 from a cohoused, infected donor cage mate. These data suggest that oral administration of persimmon-derived tannin may help reduce the severity of SARS-CoV-2 infection and transmission of the virus.

Furukawa R ，Kitabatake M ，Ouji-Sageshima N ，Suzuki Y ，Nakano A ，Matsumura Y ，Nakano R ，Kasahara K ，Kubo K ，Kayano SI ，Yano H ，Ito T ... -  《-》

Coinfection by Severe Acute Respiratory Syndrome Coronavirus 2 and Influenza A(H1N1)pdm09 Virus Enhances the Severity of Pneumonia in Golden Syrian Hamsters.

Clinical outcomes of the interaction between the co-circulating pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and seasonal influenza viruses are unknown. We established a golden Syrian hamster model coinfected by SARS-CoV-2 and mouse-adapted A(H1N1)pdm09 simultaneously or sequentially. The weight loss, clinical scores, histopathological changes, viral load and titer, and serum neutralizing antibody titer were compared with hamsters challenged by either virus. Coinfected hamsters had more weight loss, more severe lung inflammatory damage, and tissue cytokine/chemokine expression. Lung viral load, infectious virus titers, and virus antigen expression suggested that hamsters were generally more susceptible to SARS-CoV-2 than to A(H1N1)pdm09. Sequential coinfection with A(H1N1)pdm09 one day prior to SARS-CoV-2 exposure resulted in a lower lung SARS-CoV-2 titer and viral load than with SARS-CoV-2 monoinfection, but a higher lung A(H1N1)pdm09 viral load. Coinfection also increased intestinal inflammation with more SARS-CoV-2 nucleoprotein expression in enterocytes. Simultaneous coinfection was associated with delay in resolution of lung damage, lower serum SARS-CoV-2 neutralizing antibody, and longer SARS-CoV-2 shedding in oral swabs compared to that of SARS-CoV-2 monoinfection. Simultaneous or sequential coinfection by SARS-CoV-2 and A(H1N1)pdm09 caused more severe disease than monoinfection by either virus in hamsters. Prior A(H1N1)pdm09 infection lowered SARS-CoV-2 pulmonary viral loads but enhanced lung damage. Whole-population influenza vaccination for prevention of coinfection, and multiplex molecular diagnostics for both viruses to achieve early initiation of antiviral treatment for improvement of clinical outcome should be considered.

Zhang AJ ，Lee AC ，Chan JF ，Liu F ，Li C ，Chen Y ，Chu H ，Lau SY ，Wang P ，Chan CC ，Poon VK ，Yuan S ，To KK ，Chen H ，Yuen KY ... -  《-》