I did this mission with both real people and hench party ~ and managed masters award.
I think the key to this mission is to *kill quick* (try getting 2 nukers); since you're dealing with lots of afflicted, you dont want to prolonged fights. And you will need a restoration rit in your party (shelter, recuperation, etc).
Why? becuz of putrid, spores <counter with recuperation>, and shelter will really help against kuunavang. No shelter ~ random target p0wnd
EDIT: I forgot to mention, bring an interrupt ranger ~ for kuunavang.