An outbreak of cholera in the Afghan capital has killed at least eight people, is feared to have infected more than 2,000 others and is on the verge of becoming an epidemic, a senior epidemiologist working to stem the spread of the disease warned Tuesday.

Health officials in the war-shattered city of about 3 million, where rubbish and sewage fill roadside ditches and water wells are polluted, disputed the figures and asserted the threat had been contained. Nevertheless, dozens of tents were being pitched in hospital gardens to isolate patients should the number of cases spike.

"An epidemic is about to break out here," said Fred Hartman, an epidemiologist and technical director for a health program backed by the U.S. Agency for International Development. "Cholera is an explosive disease. As soon as water sources are contaminated, it spreads."

The disease has been detected in wells, the source of drinking water for most Kabul residents, and irrigation ditches, while more than 2,000 sick people have been reported with symptoms that "meet the case definition of cholera," Hartman said.

Hartman said the government was well equipped to deal with the crisis and had set up an emergency task force, which had started chlorinating wells, distributing medicine to hospitals and educating the public about the disease.

"For an undeveloped, war-torn country, Afghanistan's Ministry of Health has been able to respond very well," he said.