Infect

Question d'interprétation je pense.

Est ce qu'une carte mettant de smarqueurs poisons inflige des blessures ?

Damage from a source with infect is damage in all respects. If the source with infect also has lifelink, damage dealt by that source also causes its controller to gain that much life. Damage from a source with infect can be prevented or redirected. Abilities that trigger on damage being dealt will trigger if a source with infect deals damage, if appropriate.

http://wizards.custhelp.com/app/answers/detail/a_id/2092/~/magic%3A-the-gathering%3A-infect

Yes:
Infect creatures still deal damage. That damage just results in either -1/-1 or poison counters being added.

Fun interaction: Melira is on the battlefield. You activate inkmoth nexus, which will have infect due to timestamps. You ask the judge whether inkmoth will deal damage. The answer is yes. Now inkmoth will deal damage, it will trigger things like sword of fire and ice, but it will try to add poison counters and fail to do so due to melira.

Some might question your definition of "fun"...

(I'm not one of them )