There have been 78 cases of Ebola reported in the current outbreak in North Kivu and Ituri provinces of the Democratic Republic of Congo as of Wednesday, the World Health Organization said Friday.

Of those cases, 51 are confirmed, and 27 are probable. This includes 44 deaths.

The reported cases are in five health zones in North Kivu and one health zone in Ituri, but all of the cases are linked to the "outbreak epi-center" in Mangina, the agency said.

In addition, 10 health care workers have become infected with the disease. Nine of those cases are confirmed, and the one probable case is a worker who died.

"These health care workers were likely exposed in clinics, not Ebola treatment centres (ETCs), many of which may have been infected before the declaration of the outbreak," according to a statement from WHO.

The agency is working to "increase awareness of Ebola among health care and other frontline workers, and to strengthen infection prevention and control (IPC) measures."

The affected provinces share a border with Uganda and Rwanda and are densely populated. Ongoing conflict and violence in the area pose security concerns for those working to contain the outbreak.

This is the 10th outbreak in Congo, where the virus is endemic.

This outbreak is now bigger than the previous outbreak in Equateur province that was declared over July 24. During that outbreak, 53 cases were reported, including 29 deaths, according to Dr. Tedros Adhanom Ghebreyesus, director-general of WHO. Health officials said last week that the two outbreaks are not related.

The viral hemorrhagic fever is transmitted from person to person by infected bodily fluids such as blood, saliva, feces and breast milk. It is highly infectious but not highly contagious.

Vaccination has begun in North Kivu province among health care workers and some residents.