infectiousness

例句：

1. 1. The virus is highly infectious and can spread quickly.
   这种病毒具有很强的传染性，并且传播速度很快。
2. 2. The doctor advised everyone to wear masks to prevent the spread of the infectious disease.
   医生建议每个人都戴上口罩来防止传染病的传播。
3. 3. The patient was diagnosed with an infectious disease that required immediate treatment.
   患者被诊断出患有一种需要立即治疗的传染病。