Public health officials in the Democratic Republic of the Congo (DRC) are investigating an outbreak of an undiagnosed febrile illness affecting individuals in the Panzi region. The outbreak, first identified in , has prompted a multidisciplinary response led by the DRC Ministry of Public Health, Hygiene and Social Welfare.
Initial Observations and Investigation
The initial cases presented with a range of symptoms including fever, cough, fatigue, and runny nose. The investigation commenced on , with health professionals recruiting suspected cases at local health centers on a first-come, first-served basis. A total of 82 suspected cases were identified, and samples were collected for diagnostic analysis. The case definition focused on individuals residing in Panzi from to exhibiting at least one of the aforementioned symptoms.
A team from the National Institute of Biomedical Research (INRB) was deployed to Panzi to collect clinical samples and epidemiological data. The team comprised epidemiologists, entomologists, laboratory technicians, microbiologists, and an anatomopathologist. Samples were collected before any treatment was administered to ensure accurate representation of the initial illness state.
Laboratory Testing and Sample Analysis
A multi-pronged laboratory approach was employed to identify the causative agent of the outbreak. Initial samples, including blood and oro/nasopharyngeal specimens, were shipped to the INRB in Kinshasa in three batches between and . Blood cultures were performed on 79 samples from 53 cases, with both adult and pediatric patients included. These cultures were incubated at 35°C for 5-7 days and assessed for microbial growth.
Rapid diagnostic tests (RDTs) were used to screen for Plasmodium falciparum, the parasite responsible for malaria, using a card test designed to detect a specific protein. Researchers utilized real-time multiplex PCR assays to detect a range of viral pathogens, including influenza viruses, coronaviruses, and respiratory syncytial virus (RSV). Further molecular testing included the BioFire FilmArray System, which can simultaneously detect 19 pathogens, and the Biofire BioThreat panel, designed for detecting biothreat pathogens and toxins.
To facilitate comprehensive pathogen discovery, metagenomic sequencing was performed. This involved random amplification of nucleic acids followed by both probe-enrichment using the Twist Comprehensive Viral Research Panel and sequencing on both Oxford Nanopore and Illumina platforms. The Twist panel is designed to detect over 3,000 viral species.
Anthropometric Data and Ethical Considerations
Anthropometric measurements, including weight, height, and mid-upper arm circumference (in children under five), were collected by medical doctors and local nurses following DRC national protocols aligned with World Health Organization (WHO) standards. This data provides insight into the nutritional status of affected individuals.
The outbreak investigation was conducted as an emergency response and was therefore exempt from standard ethical approval processes. However, permission to use anonymous data for publication was granted by the Ethics Committee of the Kinshasa School of Public Health (ESP-UNIKIN). The investigation prioritized collaboration with local partners throughout all stages, including study design, implementation, and data ownership. Capacity-building activities, such as outbreak investigation and bioinformatics training, were also implemented for local researchers.
Data Analysis and Ongoing Investigation
Currently, no statistical methods have been applied to the collected data. Bioinformatics analysis is underway, utilizing pipelines like atavide lite and wf-metagenomics to analyze sequencing data. These pipelines involve quality control, adapter trimming, mapping to reference databases, and assembly of genomes to identify potential pathogens. The research team is employing both read-based and assembly-based approaches to ensure comprehensive analysis.
The etiology of the fever remains undetermined, raising concerns about potential viral or bacterial infections. The DRC’s Ministry of Public Health, Hygiene and Social Welfare emphasizes the importance of accurate and timely diagnosis to prevent further transmission. The ongoing investigation aims to identify the causative agent and implement appropriate public health measures to control the outbreak.
