Ivory Coast said it would begin vaccinating health workers and others in the commercial capital Abidjan against Ebola on Monday after a case of the deadly virus was confirmed over the weekend.

An 18-year-old woman tested positive for Ebola on Saturday after travelling by bus to Abidjan from neighbouring Guinea. It is Ivory Coast’s first confirmed case of Ebola in 25 years.

Health authorities have so far identified nine people that the woman came into contact with, including three family members and six hospital staffers, the World Health Organization (WHO) told partners in a report. One suspected Ebola case is in hospital, it said.

In Abidjan, a city of 5 million, vaccinations will begin on Monday afternoon after the Ivory Coast received 5,000 doses of vaccine, the health ministry said.

In Guinea, the health ministry also said in a statement on Monday it would begin vaccinating against Ebola, although it did not say when.

The country was declared free of Ebola on June 19, after a four-month outbreak in the south killed 12 people.

Authorities believe the woman traveled from northern Guinea by bus, passing through the Nzerekore region in the southeast, where the last outbreak began.

She then crossed Guinea’s southern border into Ivory Coast and reached Abidjan several hundred kilometres farther south on Aug. 11. She was hospitalised the next day.

WHO said preliminary genetic sequencing showed a close match between the woman’s case and the 2014, 2016 Ebola outbreak, which also originated in southeastern Guinea before spreading to Liberia and Sierra.

That outbreak, the biggest ever, killed more than 11,300 people.

Ebola causes severe vomiting and diarrhoea and is spread through contact with body fluids. It typically kills about half of those it infects, but vaccines and new treatments have proved highly effective at reducing fatality rates.

Last week, Guinea confirmed one death from the Marburgvirus, West Africa’s first case of the highly infectious hemorrhagic fever which is similar to Ebola.