* Liberia closing schools, considers quarantining communities
* Suspected Ebola cases sent home as Liberian isolation unit fills
* Peace Corps pulls volunteers from 3 countries
* White House says U.S.-Africa leaders trade summit will go on
* Ebola-stricken U.S. doctor, missionary improve
By David Lewis and Emma Farge
DAKAR, July 30 (Reuters) - Liberia will close schools and consider quarantining some communities, it said on Wednesday, rolling out the toughest measures yet imposed by a West African government to halt the worst outbreak on record of the deadly Ebola virus.
"This is a major public health emergency. It's fierce, deadly and many of our countrymen are dying and we need to act to stop the spread," Lewis Brown, Liberia's information minister, told Reuters. "We need the support of the international community now more than ever. We desperately need all the help we can get."
Security forces in Liberia were ordered to enforce the action plan, which includes placing all non-essential government workers on 30-day compulsory leave.
Highly infectious Ebola has been blamed for 672 deaths in the West Africa nations of Liberia, Guinea and Sierra Leone, according to the World Health Organization. Liberia accounted for just under one-fifth of those deaths. The first cases of this outbreak were confirmed in Guinea's remote southeast early this year. It then spread to the capital, Conakry, and into neighboring Liberia and Sierra Leone.
The fatality rate of the current outbreak is around 60 percent although the disease can kill up to 90 percent of those who catch it. The illness, called viral hemorrhagic fever, has symptoms that include external bleeding, massive internal bleeding, vomiting, and diarrhea.
The U.S. Peace Corps said on Wednesday it was temporarily withdrawing 340 volunteers from Liberia, Sierra Leone and Guinea and that two of its volunteers had been isolated and were under observation after coming in contact with a person who later died of the Ebola virus.
The Peace Corp has 102 volunteers in Guinea, 108 in Liberia and 130 in Sierra Leone working in education, health and agriculture.
The State Department has confirmed that one U.S. citizen died from Ebola in Nigeria after being infected in Liberia. Two other American aid workers infected with Ebola, Dr. Kent Brantly and missionary Nancy Writebol, are in serious condition, but they have shown slight improvement. They were part of a team in Liberia from North Carolina-based Christian relief groups Samaritan's Purse and SIM.
'ONLY HEALTHCARE WORKERS WILL BE PERMITTED'
Liberian President Ellen Johnson Sirleaf said in a speech posted on the presidency's website that the government was considering quarantining several communities based on the recommendation of the health ministry. http://www.emansion.gov.lr/
An earlier draft of the measures sent to Reuters specified communities to be quarantined.
"When these measures are instituted, only healthcare workers will be permitted to move in and out of those areas. Food and other medical support will be provided to those communities and affected individuals," she said, adding that all markets in border areas are to be closed.
White House spokesman Eric Schultz told reporters that President Barack Obama had been briefed on Tuesday by his homeland security adviser, Lisa Monaco, and that the White House was monitoring the deadly outbreak.
"The CDC (U.S. Centers for Disease Control and Prevention) has said this is not a risk to the United States at this time," Schultz told reporters traveling with the president back to Washington from Kansas City, Missouri. He said the U.S. government had increased assistance to countries battling Ebola.
Schultz said the White House would proceed with a planned U.S.-Africa Leaders Summit in Washington Aug. 4-6 that about 50 Africa leaders are expected to attend to discuss trade and investment between the United States and Africa.
Liberia's President Surleaf said she would not be attending the summit but that Vice President Joseph Nyuma Boakai and a few cabinet ministers "whose presence are absolutely necessary" would attend.
"We have no plans to change any elements of the U.S.-Africa Leaders Summit as we believe all air travel continues to be safe," Schultz said.
Last week, 40-year-old Liberian-American Patrick Sawyer, a consultant for the Liberian finance ministry, died from Ebola in Nigeria after having traveled from Liberia. Authorities in Nigeria, as well as Ghana and Togo, through which he passed en route to Lagos, are trying to trace passengers who were on the same plane as he was.
On Wednesday, Britain held a top-level government meeting to discuss the spread of Ebola in West Africa, saying the outbreak was a threat it needed to respond to.
Mike Noyes, head of humanitarian response at Action Aid UK, said people affected by Ebola should be treated with compassion and not criminalized.
"Enforced isolation of a whole community is a medieval approach to controlling the spread of disease," he said. Some airlines in the region have cut routes to countries affected by Ebola, even as the WHO is saying it does not recommend travel restrictions as a step to control outbreaks.
On Wednesday, Liberian health officials said an isolation unit for Ebola victims in Liberia's capital, Monrovia, was overrun with cases and health workers were being forced to treat up to 20 new patients in their homes.
Protests by the local community against construction of an isolation unit at Elwa Hospital have ended, said Tolbert Nyenswah, an assistant minister of health, but patients with Ebola symptoms will have to wait at home until work is finished.
"The staff here are overwhelmed. This is a humanitarian crisis in Liberia," Nyenswah told Reuters by telephone.
Nyenswah said the suspected patients were being treated by trained medical staff with full protective gear, but it would take at least 24 to 36 hours to build the new unit.
Initial resistance to building a new isolation unit highlighted the fear and mistrust health workers have faced across West Africa as they battle the outbreak, which has strained the region's weak health systems.
Dozens of local health workers, including Sierra Leone and Liberia's leading two Ebola doctors, have died treating patients.
Samaritans Purse said on Wednesday it would stop running case-management centers in Liberia after an attack on employees over the weekend and resistance from the local community to the expansion of their unit in Monrovia. The organization said it was withdrawing non-essential staff from the country. (Reporting by David Lewis and Emma Farge; Additional reporting by Kwasi Kpodo in Ghana, Clair MacDougall in Monrovia, Misha Hussain for the Thomson Reuters Foundation in Dakar, Lesley Wroughton and Roberta Rampton in Washington, Colleen Jenkins in North Carolina; Writing by Toni Reinhold; Editing by Steve Orlofsky)