Last weekend the number of infections swept past 60,000, the worst case predicted by the United Nations in early December. The Times has now obtained a WHO memorandum expecting between 32,000 and 55,000 more cases.
The epidemic has already claimed 3,300 lives – greater than the toll for the whole of Africa in most years – and is one of the worst recorded. Last week there were 8,578 new cases and 324 deaths.
We are at our wits' end, one senior aid worker confided. We are not yet winning the battle, admitted Custodia Mandlhate, the WHO representative in Zimbabwe.
Another Western health official said that the epidemic would not end until May, when the rains cease and it can run its natural course.
Cholera has increasingly moved from urban to rural areas, and the small, isolated village of Numasi, with its thatched mud huts, dirt paths and tiny vegetable plots, illustrates why a small army of aid organisations has failed to tame it.
The disease arrived in Numasi on December 23, almost certainly imported by a city-dweller returning to relatives for Christmas. A middle-aged man, Iwell Phili, was the first to fall sick. Nobody knew what was wrong with him. The local white farmer who might have helped was on holiday. Within two days Mr Phili was dead, and a red flag flies from the roof of his hut to warn of danger.
In early January an old man, Everson Ngozo, developed the same symptoms – sweating, vomiting and chronic diarrhoea. The farmer sent him to the town of Chegutu, 15 miles (25km) away along a pitted track, but Mr Ngozo died on the way. The villagers were shocked. They didn't know what was happening. At first they thought someone among them was a witch and killing the others, said George Zulu, one of their number.
Margaret Phili, a woman in her sixties, developed the illness one morning and was dead that night. The day of her funeral her husband, Lapulan, developed cholera. It started in my stomach. I got diarrhoea, then I passed out. I didn't know what was happening. I thought I was going to die, he said. He, too, was taken to Chegutu, spent five days in the cholera treatment centre there, and survived.
Four other villagers were stricken and lived, but not Yusof Katumba, 14, who succumbed in less than 24 hours last week.
Western aid organisations, working with Zimbabwe's skeletal health service, have made herculean, if sometimes haphazard, efforts to counter the epidemic. They have trained or retained medics and volunteers, helped to open 235 cholera treatment centres, delivered oceans of clean water, drilled scores of boreholes, unblocked sewers, and distributed untold quantities of hygiene kits, buckets, water purification tablets and leaflets.
In urban areas this has yielded results. The Chegutu cholera centre – a canvas encampment on the edge of town – was receiving 145 cases a day when it opened in early December but now receives a mere handful. However, cholera is erupting instead in rural areas, where it is far harder to control.
Infections soared after Zimbabweans returned to their villages en masse for Christmas. The health service no longer has the vehicles, fuel or staff to venture into the countryside to educate, spray and bury. Villagers are so destitute that they have no means of reaching the urban cholera centres, and in extreme cases – especially in a population weakened by hunger – cholera can kill in four to six hours.
Most villages have no sanitation and rely on shallow wells for water, and with the rainy season in full spate many of those have been contaminated. Villagers are often unaware of the need to boil their water or wash their hands – even if they had soap. They sometimes fail to report cholera deaths, or to bury victims properly, and officials in Chegutu spoke of instances where corpses were simply abandoned.
More than 70 per cent of Zimbabwe's victims are now dying in their communities – meaning that they are unable to reach help at cholera centres. Fatalities are running at 5 per cent, far higher than need be the case for a disease easily treated with antibiotics and rehydration. But the regime of Robert Mugabe appears unconcerned about the tragedy.
Cholera is under control, Gideon Gono, the Reserve Bank governor, declared this week. Every year there is a cholera outbreak in southern Africa. The epicentre of the disease just happened to be in Zimbabwe this year.
Anatomy of an epidemic
1,828 cases diagnosed on Wednesda
27 deaths confirmed on Wednesday
90 per cent of districts affected
61 per cent of those districts reported new cases on Wednesday
3,323 have died since outbreak began in August
65,739 infections since last August
1 per cent of those infected with cholera die, under normal circumstances
5 per cent of those infected in Zimbabwe are dying because of lack of clean water
13 months since Harare's biggest township, of one million, had running water
34-year life expectancy for women in Zimbabwe, the world's lowest