31 new cases of Ebola reported in Guinea and Sierra Leone last week while 14 new cases were reported at the beginning of this week, reported CNN citing World Health Organization.
Officials were quoted as saying that these new cases mark the second straight week that the number of Ebola cases in West Africa has increased.
WHO officials have started investing on how new cases of the disease were contracted.
Read More: Death toll due to Ebola exceeds 8,100: WHO
"The outbreak is not over and the response efforts must be sustained until we get to zero cases throughout the region and are able to stay at zero for several months," the U.N. Mission for Ebola Emergency Response said Thursday.
Liberia was declared Ebola free by WHO last month only.More than 4,000 people died after contracting Ebola in Liberia last year.