An endoscope sheath for use in removing bacterial biofilm from a target site of a human patient, the sheath comprising:an elongated, flexible outer sleeve (135) adapted to receive an insertion tube of an endoscope, the outer sleeve defining a distal end maintaining a viewing window (182) andan irrigation duct (134) formed as an elongated tube having a distal end maintaining a nozzle (212), the nozzle being secured adjacent the viewing window and oriented to direct a pressurized stream of fluid away from the viewing window and directly against a layer of bacterial biofilm to mechanically remove the bacterial biofilm without substantially damaging an underlying structure of the target site.
