As of February 4, 50 suspected cases of yellow fever, with five of these confirmed, were listed in the Macenta prefecture, in the south of Guinea. "In this context, one can conclude an epidemic", said an MSF epidemiologist, who has been sent to Guinea.

Yellow fever, transmitted by mosquitos, had practically disappeared from West Africa in the 1950s and 1960s. Since the 1980s, the disease has reappeared regularly: and in Guinea, in particular.

In December 2000, nearly 500 cases were recorded in the areas of Mamou, Labbé and Kankan, in the north of the country. At that time, MSF took part in a massive vaccination campaign that provided protection for more than one million people against the disease. Fatal in 40% of the serious cases, yellow fever does not have a specific treatment.

Medication is limited to fighting the symptoms such as: fever, jaundice, haemorrhages. In the most serious cases, the liver and kidneys no longer function, and is followed by coma and then death.

Unfortunately the people with yellow fever often arrive at the hospitals too late for successful treatment: the cases can be scattered in villages very far away from the health centres.

With the absence of treatment, vaccination remains the most effective protection against the risks of epidemics.

Today, the province of Macenta, in the south of Guinea, is threatened, after 50 suspect cases and 25 deaths.

Three of these cases were recorded at the MSF clinic in the Kuankan camp, where our team has been working since last July.

This camp shelters nearly 34,000 Liberian refugees come from the area of Lofa, in the north of Liberia - an area that is still inaccessible to humanitarian aid because of the fighting between governmental forces and rebels.

Launched last Friday, the yellow fever vaccination campaign will provide protection to some 650,000 people. MSF has provided 110,000 vaccines, and brings medical and technical support to this campaign, which is being conducted by the Guinean authorities, in partnership with the World Health Organisation.

51 vaccination teams have started to criss-cross the area, and the effort has had immediate success: on the first day of the campaign, 47,300 people were vaccinated.