How did the practices of the hospital in Maridi contribute to the spread of the disease?

When Ebola Sudan appears in the Maridi Hospital, it spreads as a direct result of the medical staff's use of dirty needles. In an almost identical scenario, Ebola Zaire breaks in the district of Bumba when dirty needles are used at the Yambuku clinic. In both cases, a site that should have been an example of prevention against these viruses was ultimately the cause of greater infection.