* Guinea finds new infections in southeast region
* President says healthcare staff "dropped the ball"
* U.S. doctor says outbreak is not under control anywhere
* U.S. official rebuts call for disaster response teams
By Saliou Samb and Daniel Flynn
CONAKRY/DAKAR, Sept 3 (Reuters) - Guinea's government said on Wednesday that Ebola had spread to a previously unaffected region of the country, as U.S. experts warned that the worst ever outbreak of the deadly virus was spiralling out of control in West Africa.
Guinea, the first country to detect the haemorrhagic fever in March, had said it was containing the outbreak but authorities announced that nine new cases had been found in the southeastern prefecture of Kerouane.
The area, some 750 km (470 miles) southeast of the capital Conakry, lies close to where the virus was first detected deep in Guinea's forest region. The epidemic has since spread to four other West African countries and killed more than 1,500 people.
"There has been a new outbreak in Kerouane but we have sent in a team to contain it," said Aboubacar Sikidi Diakité, head of Guinea's Ebola task force. He insisted the outbreak was being contained.
The nine confirmed cases were in the town of Damaro in the Kerouane region, with a total of 18 people under observation, the health ministry said in a statement.
The latest outbreak started after the arrival of an infected person from neighbouring Liberia, the ministry said. Guinea has recorded a total of 489 deaths and 749 Ebola cases as of Sept. 1.
President Alpha Conde urged health personnel to step up their efforts to avoid new infections.
"Even for a simple malaria, you have to protect yourselves before consulting any sick person until the end of this epidemic," Conde said in a televised broadcast. "We had started to succeed but you dropped the ball and here we go again."
Cases of Ebola have been reported in Liberia, Sierra Leone, Guinea, Nigeria, Senegal and Democratic Republic of Congo. The cases in Congo, which include 31 deaths, are a separate outbreak unrelated to the West African cases, however, the World Health Organization has said.
OUTBREAK NOT UNDER CONTROL
In a stark analysis last week, the WHO warned that the Ebola epidemic in West Africa could infect more than 20,000 people and spread to 10 countries. It outlined a $490 million roadmap for tackling the epidemic.
Doctor Tom Kenyon, director of the U.S. Centers for Disease Control's (CDC) Centre for Global Health, said on Wednesday the outbreak was "spiralling out of control" and he warned that the window of opportunity for controlling it was closing.
"Guinea did show that with action, they brought it partially under control. But unfortunately it is back on the increase now," he told a conference call. "It's not under control anywhere."
He warned that the longer the outbreak went uncontained, the greater the possibility the virus could mutate, making it more difficult to contain. Ebola is only transmitted in humans by contact with the blood or bodily fluids of sick people, though suspected cases of airborne infection have been reported in monkeys in laboratories.
A senior U.S. official rebutted a call from medical charity Medecins Sans Frontieres (MSF) for wealthy nations to deploy specialised biological disaster response teams to the region. MSF on Tuesday had warned that 800 more beds for Ebola patients were urgently needed in the Liberian capital Monrovia alone.
"I don't think at this point deploying biological incident response teams is exactly what's needed," said Gayle Smith, Special Assistant to the President and Senior Director for Development and Democracy on the National Security Council.
She said the U.S. government was focusing efforts on rapidly increasing the number of Ebola treatment centres in affected countries, providing protective equipment and ensuring local staff received training.
"We will see a considerable ramp-up in the coming days and weeks. If we find it is still moving out of control we will look at other options," Smith told a conference call.
The U.S. Department of Health and Human Services said on Tuesday a federal contract worth up to $42.3 million would help accelerate testing of an experimental Ebola virus treatment being developed by privately held Mapp Biopharmaceutical Inc.
Human safety trials are due to begin this week on a vaccine from GlaxoSmithKline Plc and later this year on one from NewLink Genetics Corp.
(Writing by Bate Felix and Daniel Flynn; Editing by Sonya Hepinstall)