infectious

infectious, contagious

这一对词都是形容词，又都具有“传染性的”、“传染病的”意义，但内涵和使用场合有所不同。
infectious: infectious修饰的是“间接传染的病”，指病菌通过空气、食物、水、衣服、容器等物的传染。

• tuberculosis is an infectious disease.
  肺结核是一种传染病。
• it's said that cancer is not infectious.
  据说癌症是不会传染的。

contagious: contagious修饰的是“直接传染的病”，一般指跟病人直接接触而感染的病。

• scarlet fever is a contagious disease.
  猩红热是一种传染病。
• measles and aids are highly contagious.
  麻疹和艾滋病是很易传染的。

形容词 infectious:

1. caused by infection or capable of causing infection
   同义词：infective
2. easily spread- Bertrand Russell
3. of or relating to infection

1. Diphtheria is a serious infectious disease.
   白喉是一种严重的传染病。
2. Flu is an infectious disease characterized by fever, aches and pains and exhaustion.
   流感是一种传染病，其特征是发热、全身疼痛和疲乏无力。
3. Measles is an infectious disease.
   麻疹是种传染病。
4. The flu is highly infectious.
   流感的传染性很强。
5. When you have this anthema, you are still infectious.
   身上还有这种疹子就仍然有传染性。
6. He expressed infectious enthusiasm to his voters.
   他对他的选民表现出很有感染力的热情。

in.fec.tious

adj.（形容词）
Capable of causing infection.
传染的：能够导致传染病的
Caused by or capable of being transmitted by infection.
传染性的：能以传染方式扩散的，由传染引发的
Caused by a pathogenic microorganism or agent.
传染病的：由致病微生物或媒介导致的
Easily or readily communicated:
有感染力的：容易或能快速传播的：
例句：
an infectious laugh.
有感染力的微笑

【引伸】
infec.tiously
adv.（副词）
infec.tiousness
n.（名词）