Democratic Republic of Congo's health ministry said on Tuesday that a previously unidentified disease circulating in the southwestern Kwango province is a severe form of malaria.

Earlier this month, local authorities said the disease had killed 143 people in the country's Panzi health zone in November. The symptoms of the disease are fever, headache, cough, runny nose and body aches.

"The mystery has finally been solved. It's a case of severe malaria in the form of a respiratory illness," the health ministry said in a statement, adding malnutrition in the area had weakened the local population, leaving them more vulnerable to disease.

The statement also said that 592 cases had been reported since October, with a fatality rate of 6.2%.

Provincial health minister, Apollinaire Yumba, told Reuters that anti-malaria medicine provided by the World Health Organization was being distributed in the main hospital and health centers in the the Panzi health zone.

A WHO spokesperson said more health kits for moderate and critical cases were due to arrive on Wednesday.

WHO Director-General Tedros Adhanom Ghebreyesus said last week that 10 early samples from patients in Congo suffering from a mystery illness had tested positive for malaria, but that he had not not ruled out the possibility that they suffered from other concurrent diseases. (Reporting by Yassin Kombi; Additional reporting by Sonia Rolley and Ange Kasongo; Writing by Anait Miridzhanian Editing by Bate Felix and Alex Richardson)