User blog comment:Mckrongs/Monster Hunter 4 for the Nintendo 3DS/@comment-86.171.224.79-20121215222424/@comment-2194133-20121216012448

^ I agree, I would guess that the virus takes effect around half-way through the monster's health. So it would just play out like a regular hunt. If it normally takes 20 minutes then around 10-ish the virus activates and then play out like a regular hunt except with an infected monster. That's my idea on it, we should probably wait for more information on it honestly.