CONAKRY, Guinea, Shawwal 5, 1435, Aug 1, 2014, SPA -- An Ebola outbreak that has killed more than 700 people in West Africa is moving faster than the efforts to control the disease, the head of the World Health Organization warned as presidents from the affected countries met Friday in Guinea's capital. Doctors Without Borders said its teams were overwhelmed with new Ebola patients in Sierra Leone and that the situation in Liberia was now "dire." ِِِDr. Margaret Chan, director-general of the World Health Organization, said the meeting in Conakry "must be a turning point" in the battle against Ebola, which is now sickening people in three African capitals for the first time in history, AP reported. "If the situation continues to deteriorate, the consequences can be catastrophic in terms of lost lives but also severe socio-economic disruption and a high risk of spread to other countries," she said. At least 729 people in four countries - Guinea, Sierra Leone, Liberia and Nigeria - have died since cases first emerged back in March. Two American health workers in Liberia have been infected, and an American man of Liberian descent died in Nigeria from the disease, health authorities there say. -- SPA 20:45 LOCAL TIME 17:45 GMT www.spa.gov.sa/w