Congo's health ministry says unknown disease is severe malaria. What to know.

LUBUMBASHI, Democratic Republic of the Congo – The nation's health ministry said Tuesday that a previously unidentified disease circulating in the country's Panzi health zone 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 that malnutrition in the area had weakened the local population, leaving them more vulnerable to disease.

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

In an emailed statement to USA TODAY, the World Health Organization said it hasn't determined the cause of the illness yet and was still doing lab testing. The global health agency said it wasn't aware of of the Congo ministry's statement.

Some samples arrived to WHO's lab in Kinshasa, the Democratic Republic of Congo's capital, about 48 hours by car from the Panzi health zone, which is why the disease has taken so long to identify. More samples are on the way, WHO said.

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

A WHO spokesperson said more health kits for moderate and critical cases were due to arrive 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 he had not not ruled out the possibility that they suffered from multiple diseases at the same time.

(This story was updated with new information.)

Contributing: Eduardo Cuevas, USA TODAY