A person in Sierra Leone has tested positive for Ebola, the World Health Organization (WHO) announced Friday, just one day after the organization declared an end to the outbreak in West Africa. The patient died three days ago near the Guinean border, the AFP news agency reports. Two swab tests carried out by the health organization Public Health England came back positive for Ebola, Reuters reported today. The WHO later confirmed the positive test in a statement to the AFP.

The WHO announced an end to the outbreak in West Africa yesterday, after 42 days had passed since the last confirmed Ebola patient tested negative for the virus. The organization said that "all known chains of transmission have been stopped in West Africa," though it cautioned that new "flare-ups" were still likely to occur. Ebola spreads through contact with the bodily fluids of an infected person, and is characterized by severe vomiting, diarrhea, and internal bleeding.

The virus killed more than 11,300 people since the outbreak began in 2013, and infected more than 28,500 others. The vast majority of Ebola deaths have been concentrated in Liberia (4,809), Sierra Leone (3,955) and Guinea (2,536), according to recent statistics from the WHO. Sierra Leone was declared Ebola-free in November.