A further 15 people have died from the Marburg virus in Angola, taking the death toll to 174 in the world's worst outbreak of the Ebola-like virus.
Health workers are helping to train volunteers in Luanda
The World Health Organization says that the virus has now reached the western province of Kuanza Sul - the sixth region to be affected.
The outbreak has killed an unusually high number of the 200 people infected.
A senior WHO official told the AFP news agency that the outbreak would still "get worse before it gets better".
"Everybody should be on alert," said Anarfi Asamoa-Baah, WHO's assistant director general of communicable diseases.
"Not only other provinces in Angola but all its neighbouring countries, the Congo, the Democratic Republic of Congo, Namibia and Zambia."
WHO also said that a second portable field laboratory would open shortly in the Angolan capital, Luanda.
One is already open in the province of Uige, where the outbreak started three weeks ago.
Most of those who have died have been children under the age of five.
Early symptoms of Marburg are diarrhoea, stomach pains, nausea and vomiting, which give way to bleeding.
The WHO said most of the Angolan deaths occurred between three and seven days after the onset of symptoms.
Marburg, a severe form of haemorrhagic fever, has no known vaccine or medical treatment.
Until this outbreak, Angola was not considered part of the geographical "hot zone" for Marburg, says the WHO.