In the hot zone is the army infecting the monkeys with ebola or are they bringing them in when they already have it ? please explain

THe monkey's are already infected with the virus. Jaax is asked to examine tissue samples from monkeys who are dying of an unknown virus at the Reston facility. When Jaax identifies the virus as a new strain of Ebola, the United States Army and the Centers for Disease Control coordinate a secret operation to contain the virus before it can spread to the human population.

While the Reston facility is marked as a “hot zone,” a SWAT team is tasked with entering the building, euthanizing hundreds of monkeys, and collecting blood and tissue samples for further study.