The president of the committee, Patrick Coker, said the Chinese embassy in Sierra Leone said the delegation "might find themselves in a troubled and awkward situation once they get to China's port of entry".

The Youth Olympics begin on Saturday in Nanjing, capital of Jiangsu province. The 12-day event features more than 3,000 athletes from around the world, from the ages of 15 to 18.

Seven Chinese medical staff working in the Sierra Leone-China Friendship Hospital, quarantined after treating Ebola patients, have also shown no Ebola symptoms and their conditions were stable, an official with the Chinese embassy told Xinhua News Agency on Tuesday.

The quarantine of another member of the Chinese medical team in Sierra Leone was concluded after he was checked and ruled out from being infected with the virus, the leader of Chinese medical team, Wang Yaoping, told Xinhua.

Tom Frieden, director of the US Centers for Disease Control and Prevention, said: "The bottom line with Ebola is we know how to stop it: traditional public health. Find patients, isolate and care for them; find their contacts; educate people; and strictly follow infection control in hospitals. Do those things with meticulous care and Ebola goes away."

Xiang Nijuan, a researcher of the China CDC, agreed and said that the country's technical guidelines concerning contact tracing and management, lab testing and patient transfer will soon be distributed to guide the overall response.

For instance, meticulous contact tracing means finding everyone who may have been exposed to a person with Ebola and checking for signs of illness every day for 21 days, she said.

The Ebola virus can remain in the body for weeks before making a person sick. If the contact develops a fever or other Ebola symptoms, that person is isolated and treated and the cycle starts again - and all of that person's contacts must be traced and followed for 21 days.

Helping affected areas

WHO Director-General Margaret Chan also called for effective intervention and cooperation at the international level, with demand for response to the outbreak outstripping local capacity in West Africa.

Without global partnership, the worst Ebola outbreak in history in terms of scale and severity might be catastrophic and spread to other places, she warned.

In response, China announced last Thursday humanitarian aid supplies worth 30 million yuan ($4.9 million) for three Ebola-hit countries to help contain the outbreak.

Three public health expert teams have also been dispatched to Guinea, Liberia and Sierra Leone to help distribute supplies and guide local Chinese communities on self-protection.

About 20,000 Chinese nationals live in the three countries, figures from China's Ministry of Commerce showed.

More clinical infectious disease doctors from Beijing and Hunan province are also preparing to medically assist the affected countries, Beijing health authorities said.

Chinese medical teams under a long-standing government medical assistance program continue to work at the three countries.

"China has joined the global community to boost the fight against Ebola in West Africa," said Custodia Mandlhate, the WHO representative for Kenya, adding that China's past experience with infection response will help the affected countries fight Ebola.

The involvement will also help China understand and prepare for any Ebola eventuality, said Li Qun, the emergency response chief of the China CDC.

"Our experts will gain first-hand experience treating the disease during their communication with local health workers," he said.

On Sunday, President Xi Jinping sent messages to the presidents of Guinea, Sierra Leone and Liberia to express sympathy to the three African countries over the deaths in the Ebola outbreak.

China is willing to support the three countries in containing the spread of Ebola, Xi said.