Health officials are investigating a new outbreak of a mystery disease in the town of Bomate, Congo, where cases emerged on Feb. 9. Samples from 13 patients have been sent to the National Institute for Biomedical Research in Kinshasa for testing, the World Health Organization said.

Initial results confirmed that all samples tested negative for Ebola and other hemorrhagic fever viruses, including Marburg. Some samples, however, tested positive for malaria.
Last year, a separate flu-like illness that claimed dozens of lives in another part of Congo was ultimately linked to malaria, officials said.
Health authorities continue to monitor the situation as investigations into the cause of the current outbreak remain ongoing.