Cholera has killed at least four people in an outbreak in the past three weeks in western Burundi, where more than 400 people are infected, a health ministry official said Monday.

"Cholera is back in Burundi (...). Since August 3, we have officially registered 428 cases, of whom 42 were in hospital this morning in two southern districts of Bujumbura, in the (south-western) district of Rumonge and in the (north-western) province of Cibitoke", Terence Bwarikindi, the deputy head of in the health ministry, told AFP.

"At least four people have sadly died of this disease," he added.

The area affected by cholera runs from Cibitoke, about 45 kilometres (28 miles) north of Bujumbura, to Rumonge, 80 kilometres (50 miles) south of the Burundian capital.

"Today we're mobilised to get rid of this disease and to that end, the health ministry has since Friday declared the status of an epidemic, which will mean free medical care for all those who are sick," Bwarikindi said.

The has spread in rural areas and working-class districts "where there are practically no latrines and where there is no running water," he added.

Cholera, a highly contagious intestinal infection, is transmitted by water soiled by human waste. The disease leads to , the of the sufferer, and death if the illness is not treated.