UNITED NEWS INTERNATIONAL – A recent Ebola outbreak in the Democratic Republic of Congo has spread from rural areas into a city, raising fears that it could become hard to control.

A case was confirmed by the World Health Organization on May 17 in Mbandaka, about 150 kilometers away from where the first cases were confirmed earlier this month.

The development was described by the WHO as “concerning.” The organization says it is deploying experts to the city to “conduct surveillance” and trace all contacts of the urban case.

Four thousand doses of an experimental vaccine have already been sent to the area, with more expected soon.

So far, three cases of Ebola have been confirmed. But the WHO says there are 41 other potential cases.

Ebola is transmitted to humans via wild animals like bats. It can then spread from human to human through contact with bodily fluids.

The survival rate is just 50 percent.