An undiagnosed disease outbreak in the Democratic Republic of Congo has infected more than 400 people since October, the World Health Organization (WHO) said on Sunday.
In the remote Panzi region, located more than 700 kilometres from the capital Kinshasa, 406 cases have been reported with 31 deaths, the WHO said in a statement.
The Congolese Health Ministry has reported several additional deaths outside of health facilities that need to be investigated and verified, the WHO said.
The organization said the majority of cases reported were among children, particularly those under five years of age.
"Given the clinical presentation and symptoms reported, and a number of associated deaths, acute pneumonia, influenza, COVID-19, measles and malaria are being considered as potential causal factors with malnutrition as a contributing factor," the WHO said.
The WHO said malaria was a common disease in the area and it may be causing or contributing to the cases.
"Laboratory tests are underway to determine the exact cause. At this stage, it is also possible that more than one disease is contributing to the cases and deaths."
Symptoms of the illness, locally known as Disease X, include fever, headache, cough, runny nose and body aches.