3498
Liver biopsies should be undertaken at regular intervals if azathioprine therapy is continued so that structural liver damage may be detected at an early and reversible stage .
 Chemical: azathioprine; Disease: liver damage
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
 Entities: azathioprine, liver damage 
Answer:
 Chemical: azathioprine; Disease: liver damage