The epidemic is adding to the humanitarian crisis in the country, where President Robert Mugabe and the opposition are deadlocked over a power-sharing deal and the veteran leader is resisting Western calls to step down.

An update dated January 12 showed 2,024 people had been killed by cholera from 39,806 cases. It is the worst outbreak of the disease in Africa since 1999 when 2,085 people died from cholera in Nigeria, according to WHO data.

The waterborne disease, which causes severe diarrhea and dehydration, has spread to all of Zimbabwe's 10 provinces because of the collapse of health and sanitation systems. The WHO said 89 percent of the country's 62 districts are affected.

Zimbabwe's government has warned that the epidemic could get worse in the rainy season which peaks in January or February and ends in late March. Floods may increase the spread of the disease.

Cholera has also spread to Zimbabwe's neighbors with at least 13 deaths and 1,419 cases in South Africa. Botswana, Mozambique and Zambia have also reported cholera cases.

Millions of Zimbabweans have fled to neighboring countries as the crisis at home bites, in search of jobs and better living conditions, and, more recently, medical treatment.