United Nations, Aug 4, (RHC) – The head of the World Health Organization (WHO) has expressed concerns that the Ebola outbreak in West Africa is spreading faster than efforts to contain it.

Margaret Chan further emphasized at a summit of regional leaders on Friday that failure to control Ebola could be "catastrophic" in terms of lives lost.

She, however, noted that the deadly virus, which has so far claimed 728 lives in Guinea, Liberia and Sierra Leone since February, could be halted, when well managed.

Up to 90 percent of people infected with the Ebola virus succumb to the disease.

The virus spreads by contact with infected blood, bodily fluids, organs - or contaminated environments. Patients have a better chance of survival if they receive early treatment.

Initial flu-like symptoms can lead to external hemorrhaging from the eyes and gums, and ensuing internal bleeding that may lead to organ failure.