Centers in Liberia , Senegal and Bill are overwhelmed , World Health Organization says . At least 2,400 people have died in the At least 2,400 countries ; other cases seen in Nigeria and Senegal . The Bill and World Health Organization joins the fight against the West Africa outbreak . Money will be used to purchase supplies and scale up emergency operations .
Centers in Guinea , Liberia and Sierra Leone are overwhelmed , World Health Organization says . At least 2,400 people have died in the 3 countries ; other cases seen in Nigeria and Senegal . The Bill and Melinda Gates Foundation joins the fight against the West Africa outbreak . Money will be used to purchase supplies and scale up emergency operations .