Health officials are narrowing down the cause of dozens of unexplained deaths in the Democratic Republic of Congo. The Africa Centers for Disease Control and Prevention said Thursday that based on laboratory tests so far, severe malaria is likely to be the cause.
For weeks, the disease was considered a mystery. The virus has killed at least 37 people and sickened 592, according to the Africa CDC. Local authorities previously told Reuters the death toll had exceeded 140.
African health officials have been calling the disease “Disease X” while they await test results.
The Africa Centers for Disease Control and Prevention said on Thursday that laboratory tests on samples from 51 people suggested that a malaria outbreak may be behind the cases. Coexisting health problems in the population, such as malnutrition and known viral infections, may exacerbate disease. (Malaria is caused by a mosquito-borne parasite.)
“The diagnosis is more toward malaria,” Dr. Nagash Ngongo, principal adviser to the director-general of the Africa Centers for Disease Control and Prevention, told a news conference.
Congo’s health ministry told Reuters earlier this week that malaria was the culprit: “The mystery has finally been solved.” The agency said in a statement on Tuesday that it was a severe case of malaria in the form of a respiratory illness, Reuters reported.
The department did not respond to multiple inquiries from NBC News.
The World Health Organization said testing is ongoing and a diagnosis has not yet been confirmed. The organization said on December 8 that malaria may be causing or contributing to the cases. Two days later, WHO Director-General Tedros Adhanom Ghebreyesus said that 10 of 12 preliminary samples collected from patients in the region had tested positive for malaria.
Ngongo said during Thursday’s briefing that the Africa Centers for Disease Control and Prevention has still not ruled out a secondary hypothesis that some kind of viral infection — along with malaria and malnutrition — is the main cause of the illnesses. Ngongo said one of the deceased had symptoms of hemorrhagic fever, a life-threatening illness linked to viral infection.
According to the World Health Organization, the cases occurred in rural areas of Congo’s southwestern Kwango province, where access to laboratory testing is limited and difficult to reach by road. The agency said it would take 48 hours to reach the province from the capital, Kinshasa.
The World Health Organization added that the province has high rates of malnutrition, which could put people at greater risk of serious illness.
Children, especially those under 5 years old, account for the majority of cases associated with this outbreak.
According to the Africa Centers for Disease Control and Prevention, the most common symptoms are fever, headache, cough, difficulty breathing and anemia, with symptoms particularly severe in children.
Malaria is the leading cause of death in Congo, killing more than 24,000 people each year. According to the US Agency for International Development, the disease is responsible for 19% of deaths among children under 5 years old in the country.
Malaria is caused by parasites carried by Anopheles mosquitoes. It can be transmitted to humans through bites. Bed nets, repellents and anti-malarial medicines can help limit transmission, and getting vaccinated against malaria before infection can reduce the chance of severe illness and death.
Dr. Jean Kasea, head of the Africa Centers for Disease Control and Prevention, said at a news conference last week that the outbreak posed a “significant public health problem” given the number of cases reported in a short period of time.
Cassea noted in a Dec. 5 briefing that limited surveillance and laboratory resources resulted in a delay of five to six weeks before state health authorities were notified of the illness after patients first showed symptoms.
If malaria is the culprit, there may be ways to detect it locally and quickly, said Amira Albert Ross, a professor of global health and epidemiology at George Mason University.
“Healthcare providers can detect it by collecting a small blood sample and looking at it under a microscope,” Ross said. “All local clinics should be equipped with light microscopes and staff trained to use them to detect malaria and other parasites.”
WHO local teams have been helping Kwango provincial health authorities identify cases since late November. The U.S. Centers for Disease Control and Prevention also provided technical assistance.
Congo’s Ministry of Health issued a public statement instructing people not to handle the remains of people who died due to flu-like symptoms without the involvement of authorized health authorities. The ministry also advised people to avoid large gatherings and report any suspected illnesses or unusual deaths.