1.When I played contaminated , airborne and virulent infection , and a rat attack to roll a surge

Can I take 4 infected token to the target ?

1 from to surge: infect to your target , and additional one from virulent infection

Another 1 from to no dmg , and additional one from virulent infection.

2.How long do these cards stay ? until end of the counter or question ?

3.when a arachyura use pincer attack to target 2 hero with 2 and 3 infected token both ,

and which one is correct ?

(1)take 5 infected token totally to add 5 dmg to this attack

(2)separately count .

1)Yes. If the attack deals no damage and you spend a surge, that's 1 from surge (+1) and 1 from no damage (+1) for a total of 4.

2)It says on the cards. Virulent infection only lasts for 1 turn.

3) As I read it, you may only spend 1 infection token for +1 damage per attack, just like a valor token. So, not 2 or 3 or 5, but 1.

2. The Virulent Infection only lasts for that turn, but Contaminated & Airborne last until the end of the quest, as the Trollfins rules says in the last paragraph on page 4