HARARE, Zimbabwe  Cholera swept through the five youngest children in the Chigudu family with cruel and bewildering haste.

On a recent Saturday, the children had chased one another through streets that flow with raw sewage, and chattered happily as they bedded down for the night. The diarrhea and vomiting began around midnight. Relatives frantically prepared solutions of water, sugar and salt for the youngsters, aged 20 months to 12 years, to drink.

But by morning, they were limp and hollow-eyed. The disease was draining their bodies of fluid.

“Then they started to die,” said their brother Lovegot, 18. “Prisca was first, second Sammy, then Shantel, Clopas and Aisha, the littlest one, last.”

A ferocious cholera epidemic, spread by water contaminated with human excrement, has stricken more than 16,000 people across Zimbabwe since August and killed more than 780. President Robert G. Mugabe said Thursday that the epidemic had ended, but health experts are warning that the number of cases could surpass 60,000, and that half the country’s population of 12 million is at risk.