GENEVA –  The U.N. says a serious outbreak of cholera is gripping West Africa.

A spokeswoman for the U.N. Office for the Coordination of Humanitarian Affairs says a cholera epidemic that has hit Nigeria, Chad, Cameroon and Niger could spread to neighboring countries.

The World Health Organization says 1,879 deaths have been reported in the four countries as of Oct. 3. That was from nearly 40,500 cases.

The wave of cholera started a few months ago. The U.N. says flooding in the region, as well as poor hygiene conditions and populations movements, have contributed to the "unusually high incidence of cholera."

Nigeria has experienced the highest number of deaths, nearly 1,200, in its worst cholera outbreak in two decades.