Apartment buildings are one of the most difficult to treat for bed bugs. The problem with spraying is that the insects hide in the walls and spread from unit to unit. Also, apartments with clutter make it difficult to treat walls, baseboards etc. Also, furniture in front of walls makes treatment difficult.
When an apartment has bed bugs, all adjacent units need to be treatment. This includes those next door, above and below the problem apartment. You can get rid of bed bugs by checking various online resources.
Most building managers will try to limit their costs by only treating the apartments that have problem. They often ask tenants not to discuss the problem with neighbors. As indicated, this is a mistake. Be sure to contact your neighbors, as their apartment could have been the cause, that spread to yours.
It is next to impossible to determine how an infestation started in the building. Also, contact your local hot line or local department of health.
If the initial extermination methods do not work, which are usually some combinations of vacuuming, sprays and fossil dust, the building management will either need to:
1) Fumigate the entire building or apartments affect, or
2) Use heat treatment on the entire building or affected apartments.