At least three additional cases of infection with the Marburg virus have been identified in Luanda. However, all of the cases seen in the capital city so far involve people who contracted the virus in the northern part of the country, according to health officials.

Children Under Five Most Vulnerable

The World Health Organization has sent a team of specialists to assist Angolan health authorities in combating the epidemic. The international charity Doctors Without Borders reportedly also is working on the scene to keep the virus from spreading in the densely populated capital.

The rare hemorrhagic fever, which is related to the Ebola virus, has no specific cure. As many as three-fourths of the reported deaths have been children younger than five years of age, according to the World Health Organization.

The virus is spread primarily through contact with bodily fluids. It causes symptoms similar to flu in the beginning -- headache, fever, vomiting, diarrhea -- but can rapidly progress to hemorrhaging and death. Although the cause of the mysterious disease was unknown in the early weeks, the US Centers for Disease Control identified it as the rare Marburg virus.

Death Count Likely Higher

The number of deaths caused by the epidemic is likely higher than the confirmed cases. Reuters quoted health ministry spokesman Carlos Alberto as saying that people may have died in their homes without ever making it to a hospital. Only those who have registered at hospitals have been included in the official tally.

"We've already had some help from the international community but more help would be welcome. We need cleaning materials, medicines, protective clothing, that kind of thing," Alberto told Reuters.