The World Health Organization (WHO) has suspended its efforts to contain the outbreak of the deadly Marburg virus in Angola, in the northern province of Uige, after staff in their mobile surveillance vehicles have been attacked.
Marburg is similar to the deadly Ebola virus, but UN health experts say it appears to have an even higher mortality rate and more than 200 Marburg cases have been reported since October. Almost all have died.
WHO says the attacks mean its teams have not been able to investigate reports of several new deaths in the region.
WHO spokesman on communicable diseases Richard Thompson says they are very concerned because they have begun counting every day lost in terms of how many people die, but he says this kind of reaction from local people is not uncommon in a haemorrhagic fever outbreak as they often believe that it is the "medicine people who have brought the illness to their communities."
WHO does not know when it will be able to resume its operations and is in urgent talks with provincial authorities to find a solution.
Some locals believe WHO staff have halted the spread of the disease. Marburg has no known vaccine or medical treatment.
Early symptoms of Marburg are diarrhoea, stomach pains, nausea and vomiting, which give way to bleeding.