Monrovia: Six US military planes have arrived in the Ebola hot zone with more Marines, as West Africa's leaders pleaded for the world's help in dealing with "a tragedy unforeseen in modern times."
"Our people are dying," Sierra Leone President Ernest Bai Koroma lamented by videoconference at a World Bank meeting in Washington. He said other countries are not responding fast enough while children are orphaned and infected doctors and nurses are lost to the disease.
Alpha Conde of Guinea said the region's countries are in "a very fragile situation."
"This disease is today an international threat and deserves an international response," he said, speaking through a translator.
Tom Frieden, director of the US Centers for Disease Control and Prevention, said he was reminded of the start of the AIDS epidemic.
"We have to work now so this is not the next AIDS," Frieden said.
Elsewhere, University of Maryland researchers announced that the first study of a possible Ebola vaccine in Africa was underway. Scientists say three health care workers in Mali received the experimental shots developed by the US government.
First-stage human safety testing began last month in the US and Britain.
The Ebola outbreak is in Liberia, Sierra Leone and Guinea. Mali has not had any cases, but it borders Guinea, and health authorities there are on guard.
If the vaccine appears to be safe, larger trials could be done in the outbreak zone early next year.
The fleet of planes that landed outside the Liberian capital of Monrovia consisted of four MV-22 Ospreys and two KC-130s.
The 100 additional Marines bring to just over 300 the total number of American troops in the country, said Major General Darryl A Williams, the commander leading the US response.
Williams joined US Ambassador to Liberia Deborah Malac at the airport to greet the aircraft.
As vehicles unloaded boxes of equipment wrapped in green-and-black cloth, the Marines formed a line on the tarmac and had their temperatures checked by Liberian health workers.
Meanwhile, British authorities said they would introduce "enhanced" screening of travelers for Ebola at Heathrow and Gatwick airports and Eurostar rail terminals.