(Bloomberg) -- Ivory Coast’s discovery of its first Ebola case in almost three decades led the West African government to vaccinate more than 4,000 people against the deadly hemorrhagic fever. Then it found out the diagnosis was wrong.

The suspected case, an 18-year-old woman, had taken multiple buses for the five-day trip from the Labe region in Guinea, through its second-largest city of N’zerekore, before reaching the Ivorian commercial hub of Abidjan. That complicated a hunt for contacts along a journey of more than 1,500 kilometers (932 miles), with more than 140 people identified. 

The original diagnosis on Aug. 14 prompted the World Health Organization to release $500,000 to support the Ivorian response and triggered a new hunt for cases in Guinea. Ivory Coast’s neighbor was declared Ebola-free in June, after an outbreak that claimed 12 lives.

Guinea was one of three countries where an Ebola epidemic in 2014-16 infected 45,000 people.

The young woman developed a fever after setting off on her journey. The symptoms worsened to include a headache and bleeding from her gums by the time she arrived in Abidjan, a city of almost 5 million people, the WHO said in an earlier report. Her diagnosis was confirmed by the Institut Pasteur in Abidjan before new tests by a lab in Lyon, France, came to a different conclusion, the WHO said on Aug. 31.

By that time, the wrongly diagnosed Ebola case had reverberated through the region. At least 1,400 Ivorian health workers grappling with the coronavirus pandemic were vaccinated against Ebola. Neighboring Burkina Faso reported a suspected case of the viral disease on Aug. 23 before dismissing it after testing.  

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