The World Health Organization stated in a briefing released on February 25 that regarding the unknown disease that recently emerged in the northwest region of the Democratic Republic of the Congo, preliminary investigations showed that the first 3 cases were all young children, who became ill and died after eating dead bats. As of February 15, the Equateur Province of the Democratic Republic of the Congo had reported two clusters of disease, with a total of 431 people falling ill and 53 deaths within more than one month. The symptoms of the patients were mostly fever, headache, diarrhea, etc., and some people developed bleeding symptoms such as epistaxis and hematemesis. According to preliminary investigations, the first cases appeared in Boloko Village, Bolomba area, which were 3 children under 5 years old, who died from January 10 to 13 respectively. The WHO Regional Office for Africa stated that these children began to have fever, headache, diarrhea, and fatigue after sharing a dead bat, and later developed more severe bleeding symptoms. In the following days, similar cases appeared one after another in this village and the nearby Danda Village. As of January 27, a total of 12 cases were reported in the Bolomba area, including 8 deaths. On February 13, the provincial health department reported the second cluster of disease, with the outbreak location in Basankusu area adjacent to the Bolomba area, concentrated in Bomate Village. Among the 419 cases in this village, 45 people died. Nearly half of the fatal cases died within 48 hours after the onset of symptoms. "The rapid increase in cases within a few days poses a serious threat to public health," Tarik Jasarevic, WHO spokesperson, mentioned on February 25, "The exact cause is still unclear." The report stated that the health department has not found clear evidence showing a connection between these two clusters of diseases. Due to the remote location of the affected villages, backward health infrastructure, the treatment, prevention and control, and investigation are all very difficult. Investigators have collected samples from multiple cases in these two areas, and initially ruled out the possibility of Ebola virus and Marburg virus. At this stage, they are working to investigate other possible causes locally, including malaria, food poisoning, typhoid, meningitis or other hemorrhagic fevers, to determine whether the cause of the disease "is an infection or a certain toxic substance".