Cleaning Infected Files

Good day every body

all thanks for Norton team about 2010 version , hope Symantec will continue in this way

 

regarding infected files , why Norton can clean some virus like Virut 

but, can't clean  some  viruses like : alman , sality , Jeefo ....

 

 

like those files

does symantec will add them in future  ?

 

also I noticed that Nod like example can clean Jeefo but, can't clean Virut !