The ebola outbreak currently spreading through West African countries is "serious" and not under control, an expert with the World Health Organisation has said.
On Wednesday in Geneva, Pierre Formenty, a doctor with the international health body who had just returned from a trip to Guinea, said the virus, which has already claimed 186 lives in Guinea since March, and has since spread to Sierre Leone and Liberia, was not on the decline.
"The situation is serious, you can't say it is under control as cases are continuing and it is spreading geographically," Formenty said
"There was no decline. In fact it is because we are not able to capture all the outbreak that we were under the impression there was a decline," he said.
On Wednesday, Sierra Leone confirmed a second death from the Ebola virus, as the WHO warned of possible further contagion as others sick with the haemorrhagic fever had been moved out of isolation and back to their village.
"One of the seven Ebola patients, a woman admitted at the Isolation Centre in the Government Hospital in Kenema, died on Tuesday," Brima Kargbo, the chief medical officer at the hospital, told the AFP news agency.
The six other patients affected were "undergoing treatment", added Kargbo.
The announcement of the death comes two days after Sierra Leone confirmed its first fatality from Ebola.
The WHO reported two new cases, including one death, between May 25 and 27 in Guinea's capital Conakry. They were the first to be detected in the country since April 26.
An outbreak in the capital could pose the biggest threat because the city is Guinea's international travel hub.
The haemorrhagic fever, which has no cure, erupted in Guinea in January and also spread to Liberia.
Liberia has seen 12 reported cases of Ebola - six of them laboratory confirmed - including nine deaths, but no new cases have emerged since April 9.
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However, Fromenty pointed to the fluid borders between Liberia, Guinea and Sierra Leone and said: "We're on high alert in Liberia."
The WHO has described the region's first Ebola outbreak as one of the most challenging since the virus was first identified in 1976 in what is now the Democratic Republic of Congo.
In response to the epidemic, Sierra Leone has restricted travel in some areas, and reaffirmed an earlier ban on trips to attend funerals in Guinea.
Ebola is one of a handful of similar fevers that cause vomiting, diarrhoea, muscle pain, and in severe cases, organ failure and unstoppable internal bleeding.
It can be transmitted by blood and other bodily fluids, as well as the handling of contaminated corpses or infected animals.