LUSAKA (Reuters) – Zambia has shut three of South African retailer Shoprite’s Hungry Lion fast-food restaurants after their food tested positive for the bacterium that causes cholera, a government minister said on Thursday.

Zambia is struggling to contain an outbreak of the disease, which has killed 51 people and made more than 2,000 others sick in the capital Lusaka.

Local government minister Vincent Mwale said inspectors had found contaminated food at three Hungry Lion branches in Lusaka.

“We have since directed the restaurants to close and have had meetings with the management to see how hygiene conditions can be improved,” Mwale told Reuters. “We suspect that some food handlers in these food outlets may be coming from parts of the city that are the epicentre of the disease.”

Shoprite management in Zambia could not immediately b e reached.

President Edgar Lungu last week directed the military to help fight the spread of the waterborne disease.

The outbreak was initially confined to densely populated parts of Lusaka with poor sanitation, but has now spread to lower-density areas.

Neighbouring Malawi has registered 157 cases and four deaths, its health minister said.

Cholera causes acute watery diarrhoea. It can be treated with oral rehydration solutions and antibiotics, but spreads rapidly and can kill within hours if not treated.