Ebola victims quarantined in Guinea
Health workers in protective suits are treating patients in quarantine centres set up in a remote corner of Guinea where Ebola has killed at least 60 people in West Africa's first outbreak of the virus in two decades.
The aid group said it is sending mobile teams into the surrounding countryside in search of people who might have been exposed since the first cases emerged last week.
"To confine the epidemic, it is critical to trace the entire transmission chain," said Dr Esther Sterk, a tropical medicine adviser for the medical group.
"All individuals who have had contact with patients who may be contaminated are monitored and isolated at the first sign of infection. The affected communities must also be informed about the illness and the precautions to be taken to limit risks of contamination."
Six of the seven blood samples sent to France from Guinea had tested positive for Ebola, specifically the Zaire strain of the disease originating from Congo which has up to a 90% fatality rate, the World Health Organisation said.
Ebola has no vaccine or specific treatment. Its initial symptoms - high fever, weakness and headache - can mimic malaria, a much more common disease in West Africa. Once the virus has caused haemorrhaging victims can start vomiting blood or bleeding from their eyes, nose and ears.
Some 1,500 of the 2,220 cases recorded since the virus was discovered in 1976 have been fatal, experts say. So far the fatality rate in Guinea has been 70%, according to Dr Sakoba Keita, a spokesman with the health ministry.
Those statistics are fuelling fear amid the first outbreak in this part of West Africa in 20 years. So far at least 60 people have died in Guinea, a desperately poor country with limited health facilities, Dr Keita said.
The outbreak has raised alarm in neighbouring countries. Across the border in Liberia, officials are already investigating eight cases - including five deaths - suspected of having links to the Guinea cases. Those patients travelled across the border into Liberia in search of medical treatment, health officials said.
It is not clear how the first human cases developed in Guinea, though Doctors Without Borders notes that bat species living in the region's tropical forests carry the virus.
"They show no symptoms and appear to contaminate large monkeys and humans through their droppings or bites," Dr Sterk said. "Humans can also catch the virus after contact with infected animals, dead or living, or from other infected persons."
Grieving relatives also can contract the virus when they come into contact with the bodies of victims, health officials say.