Conakry - Guinea raced on Saturday to contain a deadly Ebola epidemic spreading from its southern forests to the capital Conakry, as neighbouring Senegal closed its border.
The European Union pledged $690 000 to fight the contagion, while the Senegalese interior ministry said border crossings to Guinea would be closed "until further notice".
The order affects crossings at Kolda and Kedougou in the south of Senegal which are heavily used by traders, particularly during a weekly market attended by thousands from neighbouring countries.
Eight cases of Ebola have been confirmed in Conakry, the Guinean health ministry said late on Friday, including one fatality.
Across the country, "the total number of suspected cases recorded from January to 28 March 2014 is 111 cases of haemorrhagic fever including 70 deaths ... or a fatality rate of 63%", the ministry said in a statement.
Samples taken from 45 of the suspect cases included 19 which tested positive for Ebola.
Most of the cases were recorded in southern Guinea, but the disease has spread to the capital since Wednesday.
Those infected have been put in isolation to prevent the virus from spreading, while aid organisations have sent dozens of workers to help the poor west African country combat the outbreak of haemorrhagic fever.'Deeply concerned'
The EU's aid offer came after a plea for assistance from the Economic Community Of West African States (Ecowas). The regional bloc said it was "deeply concerned" about the epidemic which presented a "serious threat to the region".
The tropical virus - described in some health publications as a "molecular shark" - leads to haemorrhagic fever, causing muscle pain, weakness, vomiting, diarrhoea and, in severe cases, organ failure and unstoppable bleeding.
No treatment or vaccine is available, and the Zaire strain detected in Guinea - first observed 38 years ago in what is today called the Democratic Republic of Congo - has a 90% death rate.
Sakoba Keita, who heads the Guinean health ministry's prevention division said it remains unclear how Ebola had arrived in Guinea.
Tests on the other cases of haemorrhagic fever are still ongoing to determine their origin.
"We hope to get [the results] quickly as these cases should be treated like Ebola as they are also deadly," he said.
Guinea is one of the world's poorest nations despite vast untapped mineral wealth, with a stagnating economy, youth unemployment at 60% and a rank of 178th out of 187 countries on the UN's Human Development Index.
The World Health Organisation said Liberia had reported eight suspected cases of Ebola fever, including six deaths, while Sierra Leone had reported six suspected cases, five of them fatal.
Ebola can be transmitted to humans from wild animals, and between humans through direct contact with another's blood, faeces or sweat, as well as sexual contact or the unprotected handling of contaminated corpses.
MSF said the spread of the disease was being exacerbated by people travelling to funerals in which mourners touch the bodies of the dead.
Guinea has banned the consumption of bat soup, a popular delicacy in the country, as the fruit bat is believed to be the host species.