* Close to 400 additional deaths reported since last week
* Guinea finds new infections in southeast region
* President says healthcare staff "dropped the ball"
* U.S. doctor says outbreak is not under control anywhere
By Toni Clarke and Saliou Samb
WASHINGTON/CONAKRY, Sept 3 (Reuters) - The United Nations said it would take $600 million in supplies to control an outbreak of Ebola in West Africa as the death toll from the worst ever epidemic of the virus topped 1,900 and Guinea warned it had penetrated a new part of the country.
The pace of the infection has accelerated, with close to 400 deaths in the past week, officials said on Wednesday. It was first detected deep in the forests of southeastern Guinea in March.
The hemorrhagic fever has now spread to five countries in the region and has killed more people than all outbreaks since Ebola was first uncovered in 1976.
"This Ebola epidemic is the longest, the most severe and the most complex we've ever seen," said Dr. Margaret Chan, director-general of the World Health Organization (WHO) at a press conference in Washington, adding that there were more than 3,500 cases across Guinea, Liberia and Sierra Leone.
Dr David Nabarro, senior U.N. Coordinator for Ebola, said the cost of getting the supplies needed by West Africa countries to control the crisis would amount to $600 million. That was higher than an estimate of $490 million by the WHO last week.
Dr Rick Sacra, a 51-year-old Boston physician infected with Ebola in Liberia, could be medically evacuated as soon as Thursday, according to staff at the hospital where he worked. Two other Americans recovered from the virus after being taken for treatment in the United States last month.
Guinea, the first country to detect the virus, previously said it was containing the outbreak but announced that nine new cases had been found in the prefecture of Kerouane, some 750 km (470 miles) southeast of the capital Conakry.
"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.
The latest outbreak started after the arrival of an infected person from neighbouring Liberia, and a total of 18 people were under observation in the region, the health ministry said.
Guinea has recorded a total of 489 deaths and 749 Ebola cases as of Sept. 1, and the epicentre of the outbreak has shifted to neighbouring Liberia and Sierra Leone.
Guinean President Alpha Conde urged health personnel to step up their efforts to avoid new infections. Health workers have been hard hit by a disease that is spread by physical contact, with more than 120 killed in the three worst-affected countries.
"Even for a simple malaria (case), 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."
The haemorrhagic fever is also gaining a foothold in Nigeria where 17 cases have been reported, including three in the oil hub of Port Harcourt. The WHO warned that the outbreak there "has the potential to grow larger and spread faster than the one in Lagos" as containment measures had been less effective.
The fifth country infected was Senegal, which confirmed its first case last week: a student who slipped across the border from Guinea and made his way to the coastal capital Dakar.
More than 50 cases of Ebola have also been reported in a remote northern jungle region of Democratic Republic of Congo, although these are not linked to the West African cases.
Since Ebola was first detected in Congo in 1976, WHO has reported more than 20 outbreaks in Africa and 1,590 victims.
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.
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 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. (Additional reporting by Toni Clarke in Washington, Daniel Flynn and Bate Felix in Dakar; Writing by Bate Felix and Emma Farge; editing by Jane Baird)