Is this item useable during Survival? I bought it expecting to use it and receive the achievement and there isn't a use option.

The achievement is not listed as retired. As far as I know you can still get it. Possibly it isn't "active" until survival?

I'd submit a ticket and ask if its broken or its not supposed to be active until the event.

Just did. I'll let you know what they say.

I'll add to the note at SubetaLodge once we know :)

I'm still waiting for a little more info, but apparently the Amoricide was disabled during Survival, because it was overriding people's infections. I am waiting to find out whether or not it will be available again.

Edit: They do not know whether or not the Amoricide will ever be usable again. I suggested in the feedback section that they retire the achievement until such time as the item is again usable.