DAKAR, Senegal -- The Ebola outbreak ravaging West Africa is "totally out of control," according to a senior official for Doctors Without Borders, who says the medical group is stretched to the limit in its capacity to respond. International organizations and the governments involved need to send in more health experts and to increase the public education messages about how to stop the spread of the disease, Bart Janssens, the director of operations for the group in Brussels, told The Associated Press on Friday.

Ebola has already been linked to more than 330 deaths in Guinea, Sierra Leone and Liberia, according to the latest numbers from the World Health Organization. The outbreak, which began in Guinea either late last year or early this year, had appeared to slow before picking up pace again in recent weeks, including spreading to the Liberian capital for the first time. "I'm absolutely convinced that this epidemic is far from over and will continue to kill a considerable amount of people, so this will definitely end up the biggest ever," he said.

The multiple locations of the outbreak and its movement across borders make it one of the "most challenging Ebola outbreaks ever," Fadela Chaib, a spokeswoman for the World Health Organization, said earlier in the week.

But Janssens' description of the Ebola outbreak was even more alarming, and he warned that the governments affected had not recognized the gravity of the situation.

The governments involved and international agencies are definitely struggling to keep up with the severity of the outbreak, said Krishnan of Plan, which is providing equipment to the three affected countries and spreading information about how people can protect themselves against the disease. But he noted that the disease is striking in one of the world's poorest regions, where public health systems are already fragile. "The affected countries are at the bottom of the human development index," he said in an emailed statement. "Ebola is seriously crippling their capacities to respond effectively in containing the spread."

"The situation requires a more effective response," said Janssens of Doctors Without Borders. "With more than 40 international staff currently on the ground and four treatment centres, Doctors Without Borders has reached its limit to respond," he said.

"It's the first time in an Ebola epidemic where (Doctors Without Borders) teams cannot cover all the needs, at least for treatment centres," he said.

The disease typically strikes sparsely populated areas in central or eastern Africa, where it spreads less easily, he said. By contrast, the epicenter of this outbreak is near a major regional transport hub, the Guinean city of Gueckedou.

He said the only way to stop the disease's spread is to persuade people to come forward when symptoms occur and to avoid touching the sick and dead. "There is still not a real change of behaviour of the people," he said. "So a lot of sick people still remain in hiding or continue to travel. And there is still news that burial practices are remaining dangerous."

Associated Press writer Jonathan Paye-Layleh contributed to this report from Monrovia, Liberia