Frequency of Laboratory-Confirmed Malaria and Etiological Profile of Acute Febrile Syndromes among Hospitalized Adults in Kinshasa, Democratic Republic of the Congo: A Retrospective Evaluation

In the Democratic Republic of the Congo, a fever has long been treated as a certainty: it is malaria. This assumption is so deeply rooted in medical practice that when an adult arrives at a hospital with a high temperature, doctors often prescribe antimalarial medication immediately, sometimes without running any tests to confirm the presence of the parasite. This reflex is understandable given the country's heavy burden of malaria, but it creates a dangerous blind spot. In regions where the disease is common, many healthy adults carry low levels of the malaria parasite in their blood without feeling sick. When these individuals fall ill with something else entirely—such as a severe bacterial infection that spreads through the bloodstream—a positive test for malaria can trick a doctor into thinking the fever is caused by the parasite, leading them to ignore the real, life-threatening bacterial cause. This study asks a critical question: in a major city hospital, is the fever actually malaria, or is it something else that requires different, urgent treatment?

Researchers at the University Clinics of Kinshasa looked back at the medical records of 135 adults who were admitted to the hospital between January 2023 and December 2024 with a documented fever. They wanted to see what was truly causing these illnesses and whether the standard practice of assuming "fever equals malaria" was holding up. The team reviewed every detail of the patients' stays, from their initial symptoms and test results to the final diagnosis and whether they survived. They found that the reality on the ground was far more complex than the traditional assumption suggested. In fact, the most common cause of these severe fevers was not malaria at all, but invasive bacterial sepsis, a condition where bacteria enter the bloodstream and trigger a body-wide reaction that can shut down organs.

The study revealed a startling gap in how patients were evaluated. Of the 135 adults admitted with a fever, only about 56 percent received a biological test to check for malaria upon arrival. The remaining 44 percent were treated based purely on the clinical picture of a fever, with no laboratory confirmation. Even among those who were tested, the results were often misinterpreted. The researchers found that bacterial sepsis was the primary driver of illness, accounting for more than half of all cases. Malaria, while still a significant factor, was the final diagnosis for only about 37 percent of the patients. Central nervous system infections, such as meningitis, made up another large portion of the cases. The data showed that the hospital was seeing a population of older adults, with an average age of 56, many of whom had been waiting more than a week before seeking care, likely because they had tried to treat themselves at home first.

A particularly dangerous pattern emerged from the data regarding patients who had both a fever and a positive malaria test. The researchers found that nearly 17 percent of these patients were actually suffering from a severe bacterial infection, not malaria. Because their blood tests showed the malaria parasite, doctors likely assumed the fever was caused by the parasite, missing the bacterial infection that was actually killing them. This phenomenon, known as incidental parasitemia, occurs when an adult who is already carrying the malaria parasite without symptoms gets sick from a different cause. The study also found that some patients who tested negative for malaria were still treated with antimalarial drugs because doctors did not trust the negative result, a practice that delays the administration of the antibiotics these patients desperately needed.

The consequences of these diagnostic errors were severe. The overall death rate for the group of patients in the study was 60.7 percent. However, the risk was not evenly distributed. Patients whose fevers were caused by non-malarial infections, particularly bacterial sepsis, died at a much higher rate than those with confirmed malaria. The death rate for the non-malaria group was nearly 70 percent, compared to 46 percent for the malaria group. This difference suggests that when doctors miss a bacterial infection because they are focused on malaria, the patient is far less likely to survive. The patients who died from non-malarial causes were often admitted to the intensive care unit, indicating the extreme severity of their condition, whereas those with malaria were more often managed in the general infectious disease ward.

The findings from Kinshasa challenge the long-held belief that a fever in this region is automatically malaria. The study indicates that in a tertiary hospital setting, where the sickest patients are referred, bacterial infections are the dominant cause of severe febrile illness and death. The researchers concluded that relying on clinical guesses is no longer sufficient. To save lives, doctors must systematically test for malaria to confirm or rule it out, but they must also maintain a high suspicion for bacterial infections, even when a malaria test is positive. The presence of the parasite does not guarantee it is the cause of the fever. Immediate treatment with broad-spectrum antibiotics for signs of sepsis is just as critical as treating malaria, and failing to do so carries a lethal cost. This research highlights a need to shift the medical mindset from a reflexive assumption to a rigorous, evidence-based approach that looks for the true cause of the fever before it is too late.