The mystery disease affecting people in the Democratic Republic of the Congo most likely is caused by a respiratory virus exacerbated by malaria and malnutrition, according to a report released by the WHO on Friday. This assessment contrasts with earlier reports that the illness previously called “disease X” resulted from severe malaria. The current report, however, is in line with the hypothesis put forth by the Africa CDC that the illness could be caused by a viral infection on a background of malaria and malnutrition.
Laboratory tests showed that 64 out of 89 samples (72%) obtained from patients were positive for common respiratory viruses. Most commonly, these samples were positive for influenza A virus, rhinoviruses, or SARS-CoV-2 virus, the pathogen that causes Covid-19. Over 60% of the samples analyzed were positive for malaria. Malaria, typically caused by Plasmodium falciparum, is quite common in the DRC, with approximately 12% of all cases and deaths worldwide occurring within this country. The malarial burden is especially high in children.
The WHO report also provides an update on the current disease situation. 891 cases and 48 deaths have been reported. The disease burden remains highest among children, with roughly half of all reported cases and deaths occurring in children under the age of five. In adults, 66% of cases have occurred in women. WHO officials speculate that this gender difference may result from differential household transmission dynamics that reflect an increased role of mothers caring for sick children. The cases remain limited to the Kwango Province.
The severity of the disease in children almost assuredly is exacerbated by malnutrition. The WHO report states that, “the affected area experienced deterioration in food security in recent months, with increasing levels of acute malnutrition.” The report also states that roughly 4.5 million children under the age of five in the DRC, “are facing or expected to face acute malnutrition.” Additionally, over three and a half million pregnant or breastfeeding women may experience severe malnutrition. This level of food insecurity will lead to worsening outcomes for a host of infectious diseases.
The WHO report concludes by concluding that the risk to the local community is high. The national, regional, and global risks, in contrast, are low.
Although the report provides strong evidence that the mystery disease can be tied to common respiratory viruses, more work needs to be done. Samples from only a limited number of the patients have been analyzed. Increased surveillance in the area and increased testing must continue. Additionally, the report highlights the myriad factors that can influence the severity of infectious diseases. The currently available information suggests that this disease is not caused by a novel pathogen. Rather, the evidence shows us the increased burden that known pathogens can have among vulnerable populations.
