Mystery illness kills over 50 people in the Democratic Republic of the Congo

An unidentified illness has killed more than 50 people in the Democratic Republic of the Congo since mid-January, according to the World Health Organization (WHO).

Health officials reported the first cases of the mysterious disease in the northwestern village of Boloko. The start of the outbreak was traced back to three young children who died between Jan. 10 and Jan. 13. The children reportedly ate a bat before developing symptoms, which started as a fever, headache, diarrhea and fatigue and later progressed to more severe symptoms, such as vomiting blood, WHO's Regional Office for Africa reported.

Additional cases of the illness appeared in Boloko over the following days, and more happened in the nearby village of Danda. By Jan. 27, Boloko had recorded 10 cases, including seven deaths, and Danda reported two cases and one death.

Then, on Feb. 13, health authorities reported a second cluster of illnesses in Bomate, another village in northwest Congo. As of Feb. 15, there have been 431 cases and 53 deaths reported between the two regions, according to the report.

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This data reflects a case-fatality rate of just over 12%, with nearly half of the fatalities occurring within 48 hours of symptoms developing.

However, the circumstances by which people become exposed to the illness have not been established, the report notes. Officials also haven't found clear indications of disease spread between the two outbreak locations — with Boloko and Danda in one zone and Bomate in another. In other words, the two outbreaks could potentially be separate illnesses.

"The remote geography and limited healthcare infrastructure exacerbate response challenges, with overwhelmed health facilities struggling to manage cases," the report says. "Despite ongoing response efforts, significant gaps remain, including limited laboratory capacity, unclear transmission dynamics, and weak surveillance."

There is currently little information about the illnesses in Bomate, Boloko and Danda, but the WHO investigation is ongoing.

Notably, officials did send samples from 13 cases in the Bomate outbreak to the National Institute for Biomedical Research in Kinshasa, the nation's capital, the report states.

The main symptoms seen in the reported cases have included fever, chills, headache, body aches, sweating, neck stiffness, cough, vomiting, diarrhea and abdominal cramps. Some have also involved nosebleeds, vomiting blood and tarry, black stool. These symptoms can also be seen in hemorrhagic fevers, a group of diseases caused by several families of viruses found in animals, including bats and rodents.

However, the samples from Bomate came back negative for common viruses behind hemorrhagic fever, namely Ebola and Marburg viruses, the report says. Five clinical samples from Boloko and Danda were also sent off for analysis, and those also came back negative for Ebola and Marburg.

Some of the samples from Bomate did come back positive for the parasitic disease malaria, which is endemic to Africa and kills hundreds of thousands on the continent each year.

In the fall and winter of 2024, an outbreak of illness in the Panzi health zone in southwestern Congo turned out to be caused, at least in part, by malaria. At first, it was difficult to attribute the illnesses to malaria, because at that time of year, many people in the area carry parasites in their blood but might not show symptoms. A lack of labs in the health zone made it difficult to run diagnostics and rule out other causes of the illnesses. There was also at least one case of what seemed to be hemorrhagic fever, which complicated the picture.

Regarding the new mystery outbreaks, the WHO regional office said that diagnoses under investigation include malaria, viral hemorrhagic fever, food or water poisoning, typhoid fever and meningitis.

According to a 2022 WHO report, there was a 63% surge in the number of disease outbreaks spread from animals to humans in Africa between 2012 and 2022. Ebola and other viral hemorrhagic fevers made up nearly 70% of those outbreaks, with most of the increase observed in the Democratic Republic of the Congo and Nigeria.

Part of the increase could possibly be attributed to enhanced surveillance and testing in these countries — in other words, more outbreaks are being documented than before. But the WHO report also pointed to population growth and urban expansion leading to humans encroaching on wildlife habitats, potentially leading to more chances for diseases to jump from animals to people.