GENEVA -- The Ebola outbreak caused by the Bundibugyo virus in the Democratic Republic of the Congo (DRC) and Uganda constitutes a Public Health Emergency of International Concern, falling short of a "pandemic emergency," the WHO said on its official website on Sunday.

According to data released by WHO, as of May 16, eight confirmed cases, 246 suspected cases and 80 suspected deaths have been reported in the DRC's Ituri Province, plus one confirmed case in Kinshasa, the DRC's capital. Moreover, two confirmed Ebola cases imported from the DRC were reported in Kampala, Uganda's capital, with no apparent epidemiological link between them.

At least four healthcare workers in the affected areas have died from Ebola virus disease, raising concerns about nosocomial transmission. The WHO said there are significant uncertainties regarding the true number of infected persons and the geographic spread associated with the event, as well as a limited understanding of the epidemiological links between known or suspected cases.

The WHO said that it will convene an Emergency Committee as soon as possible to provide advice on response measures for affected countries. At present, there are no approved specific therapeutics or vaccines for the Bundibugyo virus.

According to WHO, the high positivity rate of initial samples, the confirmation of cases in both Kampala and Kinshasa, and the increasing trends in suspected cases and deaths across Ituri Province all point to a potentially much larger outbreak than is currently being detected and reported. The ongoing insecurity, humanitarian crisis, high population mobility, the urban or semi-urban nature of the current hotspots, and the large network of informal healthcare facilities further compound the risk of spread.