"This is one case where a remarkably small amount of money could make an enormous difference," WHO said in launching the two-year emergency programme. "But we need to act now."

Leishmaniasis, estimated to affect 12 million people in 88 countries, thrives in poor urban areas, where it spreads rapidly among concentrated populations and bad sanitary conditions.

Philippe Desjeux, in charge of leishmaniasis control for WHO, said that at least 300,000 Afghan refugees returning to Kabul as well as international aid workers were also at risk as they lacked immunity.

"There is a huge epidemic in Afghanistan... It is not a fatal disease but highly disfiguring with a strong stigma and exclusion of the family," Desjeux told a news briefing.

"If we can be very massive in our intervention, on a large-scale in Kabul, we can change the situation," he added.

At least 200,000 people are believed to be infected in Kabul, along with an estimated 70,000 people in three other major Afghan cities - Herat, Kandahar and Mazar-i-Sharif - Desjeux said.

Treatment is through a drug called pentavalent antimonies, which is injected around the skin lesions. But Desjeux said the first oral drug, thus far used for treating the deadly form known as visceral leishmaniasis, appeared to be effective also against the more common type, cutaneous leishmaniasis, which has broken out in Afghanistan.