FREETOWN, Sierra Leone (AP) -- A corpse has tested positive for Ebola in Sierra Leone, officials said Friday, the day after the World Health Organization declared the outbreak over in West Africa.
Tests on a 22-year-old woman who died earlier this month in Sierra Leone's north proved positive for the virus, Francis Langoba Kellie, spokesman for the Office of National Security, told a local radio program.
She came from the Northern Kambia District and went to the Northern Tonkolili District for medical attention, he said. Authorities are tracing her contacts and have dispatched teams to the area for investigations. Certain areas will be quarantined, he said.
The World Health Organization confirmed the new case that comes during a 90-day period of heightened surveillance, saying that Sierra Leone's government acted rapidly. Authorities are initiating control measures to prevent further transmission, it said.
WHO declared an end to the deadliest Ebola outbreak ever on Thursday after no new cases emerged in Liberia. It had been at least two weeks since Ebola had been seen in Guinea or Sierra Leone. The three countries were most affected by the epidemic that began two years ago.
"Our level of preparedness and response capabilities are very high and there is no cause for concern," said Kelly. "We encourage the public to continue to practice the hygiene regulations which were in force during the period while Ebola was raging and the emergency regulations are still in force."
The organization warned that flare-ups were still possible.
"We are now at a critical period in the Ebola epidemic as we move from managing cases and patients to managing the residual risk of new infections," Dr. Bruce Aylward, WHO's Special Representative for the Ebola Response said Thursday. "We still anticipate more flare-ups and must be prepared for them."
Nearly 4,000 people had died before Sierra Leone was declared free from transmission of Ebola on Nov. 7. Guinea marked that day on Dec. 29.
Liberia was first declared free of the disease in May, but new cases emerged two times — forcing officials there to restart the clock. Thursday marked its third time being declared free from transmission.
Ebola has killed more than 11,300 people, mostly in West Africa, since it emerged at the end of 2013.
WHO declares Ebola transmission over when a country goes through two incubation periods — 21 days each — without a new case emerging. Countries are then placed on a 90-day heightened surveillance.
Ebola is spread through direct contact with the bodily fluids of people who are sick or bodies of the dead.
WHO says that flare-up cases, such as in Liberia, "are likely the result of the virus persisting in survivors even after recovery." Of particular concern is the fact it is now known that Ebola is present in the semen of some male survivors up to a year later. The WHO said Thursday that Ebola can "in rare instances be transmitted to intimate partners."