It is advised to use acid rounds against them. If you didn't have, use the shotgun with care. Luckily, they will appear a few times in the game. Take big care if you want to evict them, their poison multiply the damage you receive, dying very fast.
Since you can't get poisoned in this game, the sweepers act just like the normal hunters. A boss in the game is a Giant Sweeper, that only do more damage.
Darkside Chronicles =
As in Resident Evil Survivor 2, the Sweepers in Darkside Chronicles behave as any other Hunter.