14945
It is a highly conserved feature of the active site across all influenza A and B viruses and is of particular interest because compounds NA inhibitors ( NAIs ) can be cross - reactive against multiple types and subtypes of influenza .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None