A day after the World Health Organization declared the Ebola epidemic finally over, a new case has emerged in Sierra Leone, Reuters reported Friday. The disease that swept West Africa and infected more than 28,600 people and left more than 11,300 dead is proving to have a longer life then previously estimated.

Officials reported that Mariatu Jalloh, a 22-year-old female student in Sierra Leone, died Jan. 12 after falling ill at the beginning of 2016. The woman was living in a house with 22 other people and reports indicate that at least 27 people could have been exposed to the disease. Quarantines are likely to follow as authorities work to identify those exposed.

“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,” said Dr. Bruce Aylward of the World Health Organization, according to NPR.

The Ebola epidemic broke out in 2014, hitting Guinea, Sierra Leone and Liberia and leaving thousands dead. With aid workers and people traveling in the region, cases were also confirmed in Nigeria, Senegal, Spain, the U.S., Mali and the U.K., according the Centers for Disease Control and Prevention.

The WHO typically waits 42 days after the last patient tests negative to declare an end to an epidemic. The news comes only a day after officials declared the entire epidemic over in West Africa. The WHO confirmed the Jalloh case, saying there is an “ongoing risk of new flare-ups of the virus in affected countries.” It remains unclear what the timeline is for possible new cases to emerge.

“The Sierra Leone government acted rapidly to respond to this new case,” said the U.N. health agency. “Through the country’s new emergency operations center, a joint team of local authorities, WHO and partners are investigating the origin of the case, identifying contacts and initiating control measures to prevent further transmission.”

Countries are currently working to find homes for Ebola orphans. Of the more than 11,300 people who died, more than 3,000 were children.