Dash 8-400
Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Wake Vortex Encounter
Flight Crew Returned To Clearance
Environment - Non Weather Related; Procedure
This was my leg to fly. We were being vectored for the approach. Over the radio it sounded like there were three other aircraft in front and we were behind a heavy Airbus. Then ATC gave altitude; speed and heading to fly. In a very short time be were in moderate to severe turbulence. The aircraft rolled left and right and  [changed] pitch. The autopilot disconnected automatically so the Captain and I grabbed the controls. Then the Captain said 'I have the controls'. He then returned the aircraft [to] the assigned altitude; heading; and speed and re-engaged the autopilot. Captain then advised ATC of what just happened.
When I took the controls we were supposed to be at 3;000 FT. I noticed that we had descended to 2;730 FT. I immediately corrected the altitude deviation and notified ATC of the abrupt wake turbulence. ATC made no comment as to our deviation. The flight/approach continued with no other issues.It would have been nice if ATC had provided adequate traffic separation and/or provided direction as to where the heavy Airbus was.
A Dash 8-400 encountered wake vortices from a heavy Airbus on approach to EWR.