Famine-hit Somalia is facing a cholera epidemic amid poor sanitary conditions, World Health Organization officials say.

A majority of randomly collected samples of acute watery diarrhea collected from 4,272 patients in Mogadishu tested positive for cholera, the WHO said.

What is cholera?

Cholera is an intestinal infection caused by the bacterium Vibrio cholerae. You get it from drinking contaminated water or eating contaminated food. About five per cent of infected people will become severely ill and develop profuse watery diarrhea, vomiting and leg cramps.

In severely ill people, cholera will cause rapid dehydration and shock. A severe case left untreated could cause death within a few hours.

Most people who are infected don't get sick, though the bacterium can be present in their feces for up to two weeks.

"The number of cases is two or even three times than what was there last year. So we can say that we have an epidemic of cholera going on," WHO public health adviser Dr. Michel Yao told a news briefing in Geneva, Reuters reported.

So far, he said, there have been 181 acute watery diarrhea-related deaths. 

Malnourished children weakened by famine are particularly susceptible to waterborne diseases, the agency said.

The cholera outbreak is fuelled by the many informal settlements springing up in Somalia as large numbers of starving people leave their homes in search of food and other assistance, WHO said.

A lack of clean water for drinking and bathing and overcrowding in camps contribute to the spread of the disease.

UNICEF spokeswoman Marixie Mercado said Friday that tens of thousands of children have died and countless more are particularly at risk of cholera and other diseases because of drought and violence in East Africa.

With files from The Associated Press