Twenty-two more people have died of the Marburg virus in Angola over the past week, taking the toll to 277, and more deaths are feared, the World Health Organisation (WHO) said on Friday.

“The number of cases is continuing to rise slowly,” WHO spokesman Iain Simpson told journalists.

“I wouldn’t say it is out of control but I wouldn’t say it is under control either… In fact we expect that there will be more cases,” he added.

But infection control has improved at the hospital in the northern province of Uige, where two doctors remain under observation after being exposed to blood from Marburg patients in late April, the United Nations agency said.

Uige is the epicentre of the world’s worst outbreak of the Ebola-like disease, which began late last year. There have been 308 known cases to date.

The rare haemorrhagic fever is transmitted through bodily fluids including blood, sweat, saliva and tears. Most people usually die within days after massive bleeding.

Health experts say many cases have been contracted by people caring for loved ones in the final stages of illness or through washing and kissing bodies after death in accordance with local custom.

The previous record death toll from Marburg was 123 people in the Democratic Republic of Congo in 1998-2000.