An outbreak of hemorrhagic fever (search) in northern Angola has killed 95 people, mainly children under 5, the U.N. health agency said Wednesday.

The World Health Organization (search) confirmed on Tuesday that the illness was Marburg, a disease similar to Ebola (search). Analysis had identified 102 cases of the virus since October 2004, 95 of which had proved fatal. Angolan officials put the death toll at 98.

"Since the start of the outbreak, the monthly number of cases has progressively increased, but this increase could be the result of intensified surveillance," WHO said in a statement.

About three-quarters of cases have occurred in children under 5 and a small number of health care workers are among those adults infected, WHO said.

The outbreak occurred along Angola's border with Congo, in Uige province. Authorities initially feared the deaths were caused by Ebola, which still exists in nature in Congo.

"Marburg virus disease has no vaccine or curative treatment and can be rapidly fatal," WHO said. "In the present outbreak, most deaths have occurred between three to seven days following the onset of symptoms."

Previous outbreaks have indicated that the risk of infection is increased by close contact with bodily fluids of infected people, as may occur during treatment or burial practices, WHO said.

The health agency added that it is supporting efforts by Angola's Ministry of Health to improve infection control in hospitals and to intensify efforts to detect cases, as well as to improve public understanding of the disease and how it is transmitted.

"Marburg virus disease occurs very rarely and appears to be geographically confined to a small number of countries in the southern part of the African continent," WHO said. "When cases do occur, the disease has epidemic potential, as it can spread from person to person, most often during the care of patients."