Cholera is a bacterial disease spread by contaminated food or drinking water. It causes severe diarrhea and subsequent dehydration, and can kill within hours if not treated.

Squalid living conditions — contaminated water and lack of sanitation — in the country following the cyclone are the perfect breeding grounds for the spread of the disease.

The World Health Organization said earlier this week that it was sending 900,000 doses of cholera vaccine to the region.

AFP, the French news agency, reported that a cholera prevention publicity campaign had been mounted via radio and loudspeakers throughout affected towns and villages.

UNICEF has warned there is "very little time to prevent the spread of opportunistic diseases."

Cyclone Idai struck most of Mozambique nearly two weeks ago with hurricane-force winds and heavy rains. It also hit eastern Zimbabwe and Malawi.

VOA