You are presented with a paragraph from a COVID-19 literature. Classify the topics of this piece of text by choosing from the following categories:

- Epidemic Forecasting: The content relates to predictions about the spread of COVID-19.
- Treatment: The paragraph discusses therapeutic methods or medication for COVID-19.
- Prevention: The content covers measures to prevent the spread of COVID-19.
- Mechanism: The paragraph explains the biological mechanisms of the virus.
- Case Report: The content is a report of a COVID-19 case.
- Transmission: The paragraph discusses how COVID-19 is transmitted.
- Diagnosis: The content is about diagnosing COVID-19 in individuals.

Your classification should be provided as an element within a JSON array. The array should be formatted with topics enclosed in double quotes and separated by commas, following the JSON format, for example: ["Topic1", "Topic2", ...]. Include all applicable topics within the array. Your output should be a valid JSON array, and no additional text should be included in your response.

Article:

The ongoing coronavirus disease-2019 (COVID-19) pandemic, caused by a novel coronavirus termed severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) that is closely related to SARS-CoV, poses a grave threat to global health and has devastated societies worldwide. One puzzling aspect of COVID-19 is the impressive variation in disease manifestations among infected individuals, from a majority who are asymptomatic or exhibit mild symptoms to a smaller, largely age-dependent fraction who develop life-threatening conditions. Some of these differences are likely the consequence of host genetic factors. Systems genetics using diverse and replicable cohorts of isogenic mice represents a powerful way to dissect those host genetic differences that modulate microbial infections. Here we report that the two founders of the large BXD family of mice-C57BL/6J and DBA/2J, differ substantially in their susceptibility to a mouse-adapted SARS-CoV, MA15. Following intranasal viral challenge, DBA/2J develops a more severe disease than C57BL/6J as evidenced by more pronounced and sustained weight loss. Disease was accompanied by high levels of pulmonary viral replication in both strains early after infection but substantially delayed viral clearance in DBA/2J. Our data reveal that the parents of the BXD family are segregated by clear phenotypic differences during MA15 infection and support the feasibility of using this family to systemically dissect the complex virus-host interactions that modulate disease progression and outcome of infection with SARS-CoV, and provisionally also with SARS-CoV-2.
["Mechanism"]