The pathogen has certain characteristics that make it similar to the flu or COVID-19 viruses, but what raised alarm bells last week was the high mortality rate it appeared to be causing, particularly among children.
WHO's director of alert and response coordination, Abdi Rahman Mahamad, speaking at a press conference with the Association of Accredited UN Correspondents in Geneva, said that there was no longer an exponential increase in cases.
Among the explanations being considered is the possibility that the cases were malaria in malnourished children, a common problem in the areas where the pathogen was detected, he added.
WHO has helped send a team to collect available epidemiological data for analysis, which should provide "more concrete information in the next 48 hours".
Rahman Mahamad noted that such an event could have a serious impact on vulnerable communities.
Laboratory tests will rule out numerous pathogens, including haemorrhagic fever and several respiratory pathogens.
Symptoms of the disease include fever, headache, runny nose and cough, shortness of breath and anaemia.
The DR Congo, a country that borders Angola, is on "high alert" following the detection of the disease that has already caused dozens of deaths in just over a month, according to the latest estimates, the country's Minister of Public Health, Samuel Mulamba, announced on Thursday.
