An Ebola outbreak in the Democratic Republic of Congo has killed more than 80 as authorities warned there was no vaccine for the strain in a crisis that the World Health Organization declared an international health emergency on Sunday.

Officials suspect the disease has caused 80 deaths in the Democratic Republic of Congo so far.

Some 88 people have died from the highly contagious haemorrhagic fever in the DR Congo, with one death in Uganda, and at least 336 suspected cases.