He has caught the disease from his wife. 

判断方法：

1. from his wife 如果作定语修饰 the disease，那么，之间存在来源关系（说明是传染疾病），用转换为定语从句的方式判断：

He has caught the disease which comes from his wife. （成立）

所以，可以看作定语。

2. 修饰动词的状语，位置相对灵活。如果 from his wife 放在句首也能成立，那么就是状语（方式状语）。

From his wife he has caught the disease. （也成立）

就是说，from his wife 两种成分均可。