MONROVIA, Liberia – Dozens of new Ebola cases have erupted in Liberia, near the border with Sierra Leone, Liberian health officials warned Monday, marking a setback amid recent improvements.

The flare-up is due to a number of factors including people going in and out of Liberia and traditional practices such as the washing of bodies, said Liberia’s Assistant Health Minister Tolbert Nyenswah.

Forty-nine cases were reported in in western Grand Cape Mount County between December 1 and 25, Nyenswah told state radio.

“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,” he said.

About 3,400 people have died from Ebola in Liberia over the past year with nearly 8,000 cases total, though health officials say the situation has improved, especially in the capital, Monrovia.

Sierra Leone, in comparison, has now eclipsed Liberia with more than 9,400 Ebola cases, according to the World Health Organization.

Overall, more than 20,000 Ebola illnesses and nearly 8,000 deaths have been reported this year in Guinea, Liberia and Sierra Leone.