By Amy Sawitta Lefevre
BANGKOK, Aug 8 (Reuters) - Asian nations are using thermal imaging cameras and posting doctors at airports to screen out sick travellers as health authorities scramble to avert any outbreak of the Ebola virus that has killed almost 1,000 people in West Africa.
The four nations of Guinea, Liberia, Nigeria and Sierra Leone are struggling to combat the world's worst outbreak of Ebola, which has a fatality rate of up to 90 percent, with no known vaccine or cure.
The World Health Organisation declared the West Africa epidemic an "extraordinary event" and an international public health emergency on Friday.
There have been no confirmed cases of the virus in Asia, but health authorities who have battled deadly viruses, such as bird flu and the Severe Acute Respiratory Syndrome (SARS) in recent years, were dusting off the drills used for those outbreaks.
Their measures included infra-red thermal imaging cameras to screen air passengers with fevers and public awareness campaigns. Most countries have told citizens to consider postponing travel to affected areas.
Asia's efforts to screen visitors were adequate, said Tarik Jasarevic, a WHO spokesman based in Geneva.
"As long as a person is not visibly sick we think it's fine for them to be in public," he told Reuters by telephone. "We consider the risk for international spread quite low. The measures countries in Asia have taken are appropriate."
Health officials in Thailand, which received a record 26.5 million tourists last year, are monitoring 21 visitors from Sierra Leone, Liberia and Guinea. The officials said they had no plans to quarantine the visitors.
"They are free to move but we are checking in on them frequently," said Opart Karnkawinpong, a disease control official at Thailand's Ministry of Public Health.
"We have surveillance cameras in place at major entry points and doctors at international airports to supplement existing teams."
MEASURES IN PLACE
The Ebola virus is only transmitted through contact with the body fluids of someone with symptoms, which initially include muscle pains and joint aches, then worsen to vomiting, diarrhoea and internal and external bleeding in the final stages.
In China, there were no reports of Ebola cases but hospitals have been told to report any suspected cases.
India, which has nearly 45,000 citizens living and working in the four affected countries, said it would screen travellers passing through, or starting journeys there, when they returned.
"The surveillance system would be geared up to track these travellers for four weeks and detect them early, in case they develop symptoms," Health Minister Harsh Vardhan told parliament on Wednesday.
Japan is ready to send suspected Ebola victims to special isolation hospitals, Chief Cabinet Secretary Yoshihide Suga told a news conference.
In Australia, authorities said they had not taken extra steps but airports were on alert for sick travellers, saying the risk of the disease reaching the country was "very low".
Officials in Singapore said the city state, praised for its tough measures against the SARS outbreak that claimed 33 lives in 2003, also faced only a low threat from the Ebola virus.
"Measures are already in place to carry out contact tracing and quarantine all close contacts if there is a case," the health ministry said.
In Thailand, health official Opart said the 21 travellers would stay under observation for the entire incubation period, which can last up to 21 days.
"Even though Ebola is only a small risk to Thailand we are not taking any chances," he said.
(Additional reporting by Thuy Ong in SYDNEY, Rachel Armstrong in SINGAPORE, Aung Hla Tun in YANGON, Kaori Kaneko in TOKYO and Nita Bhalla of the Thomson Reuters Foundation in NEW DELHI; Editing by Clarence Fernandez)