2118
Indentification of genetic marker , HL - A W27 , for susceptible persons has provided a tool facilitating epidemiologic studies and allowing identification of " control " populations without the marker .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Disease 
Text: {0} 
 Entities:  
Answer:
 None