/ɪn'fekʃəs; ɪn`fɛkʃəs/
adj
1 (of a disease) caused by bacteria, etc that are passed on from one person to another （指疾病）传染的, 感染的
*Flu is highly infectious. 流感的传染性很强.
2 [usu pred 通常作表语] (of a person) in danger of infecting others (with a disease) （指人）能传染他人（疾病）
*While you have this rash you are still infectious. 身上还有这种疹子, 就仍然有传染性.
3 (fig approv 比喻, 褒) quickly influencing others; likely to spread to others 有感染力的; 易传播给他人的
*infectious enthusiasm 有感染力的热情
* an infectious laugh 有感染作用的笑声.

adj
an infectious illness can be passed from one person to another, especially through the air you breathe
　infectious diseases
　Flu is highly infectious.
someone who is infectious has an illness and could pass it to other people
infectious feelings or laughter spread quickly from one person to another
　an infectious smile
　infectious enthusiasm
>infectiouslyadv