Dados do Trabalho

Título

Comparison between SARS-CoV-2 variants in a Mesocricetus auratus experimental model of SARS-CoV-2 infection

Introdução

SARS-CoV-2 is responsible for more than 775 million human cases and more than 7 million deaths worldwide. SARS-CoV-2 variants were characterized by variations in the S region of SARS-CoV-2, differential ability to spread in the environment and human transmission which raised discussions about the vaccine and treatment efficacy against new emergent variants. Mesocricetus auratus (Golden Syrian hamster) is a suitable translational animal model for SARS-CoV-2 infection because it recapitulates human lung injury induced by the virus.

Objetivo (s)

his study has the objective to evaluate SARS-CoV-2 infection with different variants in a Mesocricetus auratus experimental model of SARS-CoV-2 disease.

Material e Métodos

The experimental research protocol was previously approved by the CEUA of Fiocruz and it was carried out in accordance with the Guide for the Care and Use of Laboratory Animals of the Fiocruz. Syrian hamsters were infected via intranasal with A.2, Gamma, Delta, and Omicron variants of SARS-CoV-2 and were euthanized in days 3, 5, 10 and 15 post infection. All animals were evaluated by the occurrence of SARS-CoV-2 clinical signs and mortality.  Blood obtained by total exsanguination was used to evaluate neutralization antibodies and biochemical markers. Oropharyngeal swab, lung, brain, liver and intestine were collected to evaluate the viral load by RT-PCR. Besides that, lung samples were used to assess histopathology.

Resultados e Conclusão

SARS-CoV-2 infection caused acute body weight loss with no spontaneous deaths and caused severe inflammatory lung injury. Animals infected with different SARS-CoV-2 variants showed different infection profiles. Groups infected with Delta and Omicron showed a decrease of RNA found in the oropharyngeal tract, lung and liver. The neutralization assay showed presence of neutralization antibodies at 5 DPI in all groups infected with SARS-CoV-2, except the group infected with Omicron variant. These results showed that hamster infection with Delta and Omicron variants have less severity when compared with other variants.  Despite the absence of spontaneous death among SARS-CoV-2 inoculated animals, the severe lung injury confirmed that SARS-CoV-2 successfully reproduced COVID-19 disease in Golden Syrian hamsters with difference  between variants, which justified its use to evaluate the efficacy of new vaccines and therapies.   

Palavras Chave

SARS-CoV-2; Golden Syrian Hamsters; SARS-CoV-2 variants; Experimental model