The World Health Organization (WHO) and the Ondo State Government have given different possible causes for the strange disease ravaging an Ondo State town in Nigeria’s South-West.

Pesticide poisoning was the likely cause of the mysterious deaths of at least 18 residents of Ode-Irele town earlier this week, WHO said Sunday.

The “current hypothesis is cause of the event is herbicides,” WHO spokesman Gregory Hartl said in a tweet.

“Tests done so far are negative for viral and bacterial infection,” he added.

The victims began showing symptoms early last week in what the state Commissioner for Information, Kayode Akinmade called a “mysterious disease,” prompting fears of a new infectious disease outbreak in a region ravaged by Ebola in 2014..

The victims, whose symptoms included headache, weight loss, blurred vision and loss of consciousness, died within a day of falling ill in Ode-Irele.

The Commissioner for Health, Dayo Adeyanju, told AFP on Saturday that 23 people had been affected.

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

The tests were carried out at the Lagos University Teaching Hospital, the WHO said.

However, Dr Adeyanju, told journalists on on Sunday that the disease might be as a result of the victims’ consumption of local alcohol.

He informed that the preliminary reports of tests carried out revealed that it is not a viral disease.

“The deaths might have resulted from a methanol poison drank by some of the victims,” he said.

Dr Adeyanju further said that the result of the toxicology test to confirm the statement was still being expected from the University College Hospital (UCH) Ibadan, Oyo State.

The Commissioner had earlier told journalists that the state government had deployed a team of health experts to the community to examine the victims and put the spread under control.

It has been reported that the ailment starts with a headache, blindness and eventually leads to death within few hours it attacks its victims.

Governor of Ondo State, Dr Olusegun Mimiko, has disclosed that the symptoms observed bear no resemblance to those associated with the Ebola Virus Disease or any known epidemic disease.

•Photo shows Mimiko