The WHO said, citing a new analysis from a French lab, that there was no evidence that a Guinean woman had tested positive for Ebola after arriving in neighboring Ivory Coast.
The diagnosis in mid-August was considered the first confirmed case of Ebola in a West African country since 1994.
The diagnosis triggered a major contact tracing operation by the World Health Organization, and Ivorian Medics launched a targeted vaccination campaign with women who were in immediate contact.
The 18-year-old traveled by bus from a lab in northern Guinea to Abidjan, covering a distance of about 1,500 km (950 miles) through a densely forested area where Ebola broke out earlier this year and in 2013-16. The plague had spread.
“With new laboratory findings in Lyon, the WHO believes the patient did not have the Ebola virus and further analysis of the cause of the disease is ongoing,” the UN Health Agency said in a statement on Tuesday.
The WHO said it had been notified of the new findings by the Ivorian government.
He added that after detecting more than 140 contacts with the woman, no one else showed symptoms of the disease or tested positive.
The issue sparked controversy between the two countries when Guinea requested re-confirmation of its positive test, forcing Ivorian authorities to defend the diagnosis.
Ebola, which is transmitted through close contact with body fluids, is a deadly viral disease that causes high fever and, in the worst cases, unstoppable bleeding.