Authorities in Liberia have confirmed 49 new Ebola cases in December near the West African nation’s border with Sierra Leone, Assistant Health Minister Tolbert Nyenswah said Monday. The new cases emerged despite recent indications that Ebola’s spread had slowed in Liberia.

“In a very small population, an increase in the number of [Ebola] cases raises high level of concerns that we need to take very seriously as people of Liberia and people of Grand Cape Mount in particular,” Nyenswah said, according to the Associated Press. He blamed the dozens of new Ebola cases on travel between Liberia and other affected nations, as well as the customary washing of dead bodies.

The Liberian capital city of Monrovia was seen by many as the epicenter of the Ebola outbreak that ravaged several West African nations this year. Nearly half of Liberia’s workforce was unable to contribute to the economy due to the Ebola outbreak, the World Bank said in November. Residents of the nation’s rural regions were particularly affected and food prices had skyrocketed to more than 40 percent higher than their usual rate by October.

But evidence emerged in November that the Ebola outbreak had slowed considerably in Liberia, as relief efforts and countermeasures began to have the desired effect. The appearance of new cases, which had risen as high as about 500 per day at the peak of the Ebola crisis, dropped to about 50 per day. In light of the virus’ slowdown, Liberian President Ellen Johnson Sirleaf announced at the time that she wouldn't seek to extend Liberia’s state of emergency.

The neighboring nation of Sierra Leone has since surpassed Liberia as the country most affected by Ebola, with more than 9,000 reported cases and more than 2,500 deaths. More than 1,000 new cases of Ebola have emerged in Sierra Leone in the last month. By comparison, Liberia has experienced more than 7,800 cases and more than 3,300 reported deaths in all, according to the World Health Organization.

Nearly 20,000 confirmed or probable cases of Ebola have been reported worldwide, resulting in nearly 8,000 deaths.