A "mysterious" disease that kills patients within 24 hours has claimed at least 17 lives in a southeastern Nigerian town.

"Seventeen people have died of the mysterious disease since it broke out early this week in Ode-Irele town," local government spokesman Kayode Akinmade said on Saturday.

The disease, whose symptoms include headache, weight loss, blurred vision and loss of consciousness, killed the victims within 24 hours of their falling ill, he said.

Laboratory tests have so far ruled out Ebola or any other virus, Akinmade added.

The World Health Organisation said it had information on 14 cases with at least 12 dead.

"Common symptoms were sudden blurred vision, headache, loss of consciousness followed by death, occurring within 24 hours," spokesman Tarik Jasarevic said.

Akinmade said health officials and experts from the government and aid agencies, as well as WHO epidemiologists, have arrived in Ode-Irele.

"Outside a total of 17 deaths recorded, in the past 72 hours we have not recorded new cases. There is no patient of the disease in any hospital and the disease has not spread beyond the town," he said.

Jasarevic said blood and urine samples had been taken from two victims and cerebrospinal fluid from another.

"All samples have been sent to Lagos University Teaching Hospital this morning, and results are still pending. Investigations are still ongoing," he said.