An official in Sierra Leone said a corpse has tested positive for the Ebola virus, just a day after the World Health Organization declared an end to the outbreak in West Africa.
The WHO said in a statement Friday that it confirms the Ebola case in Sierra Leone, which was detected in the body of a woman who became ill and died earlier this month.
The WHO said the discovery "shows that strong surveillance and response systems will be critical in the months to come as we must be prepared for possible flare-ups of the disease."
Free of virus
On Thursday, the World Health Organization announced an end to the Ebola virus outbreak in Liberia, meaning all three countries at the epicenter of the West African outbreak were considered Ebola-free.
The WHO announcement came Thursday after 42 days without a new reported case in Liberia.
When announcing the milestone, the WHO cautioned that more small outbreaks are expected and called for continued strong surveillance to keep the disease at bay.
The WHO representative in Liberia, Alex Gasasira, pledged that the organization will continue to support Liberia in its effort to prevent, detect and respond to any new Ebola cases.
This is the third time Liberia has been declared Ebola-free. The first declaration came in May 2015, but the disease recurred twice since then, with the latest outbreak in November.
This was the first time all three nations that hosted the outbreak -- Liberia, Guinea and Sierra Leone -- had all been Ebola-free at the same time. Sierra Leone had been declared Ebola-free on November 7 and Guinea on December 29.
More than 11,000 people died and 28,500 were infected during the Ebola epidemic in West Africa that began in December 2013.