International health workers in Angola say they are still struggling to end an outbreak of the Marburg virus, which has killed 156 people in the southern African nation.

Representatives of Doctors without Borders and the U.N. children's fund expressed concern Wednesday that the death toll continues to rise, despite emergency efforts.

The Associated Press quoted Health Minister Sebastiao Veloso as saying no new cases have been reported outside northwestern Uige province, where the rare virus was first spotted.

Hospital workers are using isolation units and protective clothing to limit the spread of the virus, which causes fever, diarrhea and bleeding.

Angola's government and aid groups have also launched campaigns to warn people that the illness can spread through contact with body fluids.

Some information for this report provided by Reuters, AP, AFP.