WHO, a specialised agency of the United Nations said the epidemic was spreading fast in three West African countries of Guinea, Sierra Leona and Liberia.
Top sources in the WHO said that although there were signs of the infection slowing down in some of the areas badly hit by the epidemic, there was not mush reason to think that the anti-Ebola operation has neared success.
According to the WHO estimates, the death toll from the outbreak of Ebola is said to have touched 4,033.
The WHO also cautioned recently that the Ebola cases were under-reported in the three West African states and it was very important to understand the scale and the pace of the outbreak of the disease in order to stop it causing more harm, the report said.
It was also said that the Ebola mortality rate was around 70 per cent, something that remained consistent across the three West African states.
Meanwhile, Doctors Without Borders, an international aid organisation said on Tuesday that nine of its 16 staff members who were affected by the virus were dead.