The Democratic Republic of the Congo (DRC) has recorded 406 cases of an undiagnosed disease between October 24 and December 5, the World Health Organization (WHO) said on Monday.

Congo’s Ministry of Public Health reported to WHO an alert regarding increased deaths from an undiagnosed cause in the Panzi health zone on November 29.

The global health agency sent experts to Panzi health zone in DRC’s Kwango Province to investigate the outbreak, which is causing fever, headache, cough, runny nose, and body ache.

“All severe cases were reported to be severely malnourished,” said the WHO.

The agency added that among the cases, “31 deaths have been registered”. Of these, 71 per cent are below the age of 15.

The WHO noted that the majority of cases reported are among children, particularly those under five years of age.

“The area is rural and remote, with access further hindered by the ongoing rainy season...and limited diagnostics which has delayed the identification of the underlying cause,” the WHO said.

While the outbreak is still ongoing, the WHO has sent teams to collect samples for laboratory testing. The results will likely provide g a more detailed clinical characterisation of the detected cases. The teams are also investigating the dynamics of the transmission, as well as actively searching for new cases -- both within health facilities and at the community level.

"Rapid response teams have been deployed to identify the cause of the outbreak and strengthen the response,” the WHO said.

The WHO suspects acute pneumonia, influenza, Covid-19, measles and malaria as potential causal factors with malnutrition as a contributing factor.

"Laboratory tests are underway to determine the exact cause," the UN agency said, noting that "more than one disease" may be contributing to the cases and deaths.