The black flies that transmit river blindness have re-emerged in parts of Ivory Coast, sparking a fresh campaign to ensure villagers can work their fields without fear.

Health workers are handing out a drug, whose distribution was stopped three years ago, that prevents the worst effects of the disease, irreversible loss of vision.

"These tablets stop you from going blind," said local nurse Mamadou Kone.

But some local people who recall the past are pushing for more radical measures.

"The situation before was dramatic," recalled Konan Kouadio, a villager in his seventies wearing large, tinted spectacles to conceal his own sightless eyes. "We had many blind people in the heart of the community."

For villages like his Kouadioa-Allaikro, in the centre of this west African country, black flies are not only a debilitating health scourge but a financial drain as well.

Agriculture is one of Ivory Coast's main sources of wealth, and the people in this region produce food crops and cocoa that are vital not only to their own livelihoods but to the country's economy as well.

The disease was curtailed in the past by dousing insecticide along the local river but such measures were stopped in 1992 due to lack of funds, according to Ivorian authorities.

In March, the country's National Programme Against Blindness (PLNCE) conducted an epidemiological study in 15 villages and confirmed that the black flies were back in force.