On Monday, Liberian health officials an outbreak of new Ebola cases, near the country’s border with Sierra Leone.

Liberia’s Assistant Health Minister Tolbert Nyenswah told state radio that forty-nine Ebola cases had been diagnosed in Grand Cape Mount County so far in December, according to a report by the Associated Press. Nyenswah attributed the increase in cases to people traveling across the Liberian border and cultural practices common to the area, such as the washing of bodies before a funeral, that can contribute to the spread of the disease.

Liberia and Sierra Leone, along with neighboring Guinea, have been the center for the recent West African Ebola epidemic, with about twenty thousand cases and almost eight thousand deaths just in the past year in the area. This new outbreak was viewed by Liberian officials as a reversal of recent improvements they had seen, especially in the capital city of Monrovia, in their fight against the deadly disease. Nyenswah said that such an increase in the number of Ebola cases among a small and concentrated population “raises high level of concerns that we need to take very seriously.”

The World Health Organization has called the Ebola epidemic in West Africa “the most severe acute public health emergency seen in modern times ” in a statement issued in September, back when the disease had infected only about six thousand people and killed almost three thousand.

After the first Ebola case to be diagnosed in the United States was confirmed earlier this year, many called for a travel ban from the affected countries. Thomas Eric Duncan, the Liberian man who was the first Ebola case in the United States, was able to enter the United States in September by denying he had had contact with anyone with the disease, and then again denied such contact the first time he went to Texas Presbyterian Hospital in Dallas. When Duncan became gravely ill and returned to the hospital, two of the nurses who treated him contracted Ebola from him. The two nurses recovered, but Duncan ultimately died from the disease on October 8th.

Current U.S. policy requires international travelers who have been in Liberia, Sierra Leone, or Guinea to undergo “enhanced screening procedures,” including testing their temperature for fever, one of the first symptoms of an Ebola infection, before they can enter the United States, but the Obama administrations has rejected calls for outright travel bans or quarantines.

Follow Sarah Rumpf on Twitter @rumpfshaker.