Maintenance for the week of October 7:
• PC/Mac: No maintenance – October 7
• Xbox: EU megaserver for maintenance – October 9, 2:00 UTC (October 8, 10:00PM EDT) - 16:00 UTC (12:00PM EDT)
They are. I stumbled on a few in the Rift early this morning (May 12) and helped a few people get bitten. They should spawn for a couple (in-game) nights in a row.