Those numbers are up from the Angola Ministry of Health's April 2 count of 150 deaths and 163 cases, provided in the World Health Organization's Monday update on the epidemic. An additional 100 contacts are being investigated by five mobile surveillance teams in Uige, in an effort to track down rumors of additional possible cases, said WHO.

All of the confirmed cases originated in Uige, though several people died in hospitals elsewhere in the country, including in Luanda, and in the Cabinda, Malange and Kuanza Norte provinces.

More International Assistance Needed

Most of the deaths -- reportedly as many as 80% -- have been among children younger than 15 years of age. Many parents are keeping their children home from school to avoid exposure. Luandan shops are said to be sold out of bleach, which people are using to disinfect their homes.

WHO is working with Angola's Ministry of Health to finalize a national plan of action for control of the outbreak, including sustained technical and operational support from WHO and international partners in GOARN. WHO anticipates that implementation of this plan will require significant assistance from the international community.

This is the largest number of fatalities ever recorded during an outbreak of this rare, but extremely severe, disease. Symptoms initially resemble flu, including headache, fever, nausea and diarrhea, but quickly progress to bleeding and, in the majority of cases, death.

Suspected Cases Isolated

In an effort to calm rising fears in response to the daily reports of more deaths from the epidemic, WHO is emphasizing the measures that can be taken to stop its spread.

Fadela Chaib, a WHO spokesperson, is quoted in press reports as saying the outbreak can be controlled if suspected cases are isolated and all their contacts are identified.

A mobile laboratory in Uige, provided by the Canadian National Microbiology Laboratory, has greatly expedited diagnostic testing.

A dedicated isolation facility, operated by Médecins sans Frontières, is preparing to receive further cases that may be identified by the mobile surveillance teams.

WHO also is working with the Ministry of Health in the Democratic Republic of Congo to train local staff in the border area near Angola in case detection and management.