Outbreak Investigation: Methods & Findings from the DRC 2024

In December 2024, a multidisciplinary outbreak investigation team responded to a cluster of illnesses in Panzi, Democratic Republic of the Congo (DRC). The investigation, led by the DRC Ministry of Public Health, Hygiene and Social Welfare, focused on individuals presenting with symptoms including fever, cough, fatigue, and body aches. The response involved extensive sample collection and laboratory analysis to identify the cause of the outbreak.

Understanding the Investigation

Rapid Response and Ethical Considerations

The outbreak investigation was initiated as an emergency response, exempting it from standard ethical approval processes. However, permission to utilize anonymous data for publication was secured from the Ethics Committee of the Kinshasa School of Public Health (ESP-UNIKIN), with approval number ESP/CE/69/2025. This highlights the commitment to responsible data handling even during urgent public health situations.

Did You Know? The outbreak investigation team included a diverse range of specialists – epidemiologists, entomologists, laboratory technicians, microbiologists, and an anatomopathologist – demonstrating a comprehensive approach to identifying the source of the illness.

Data Collection and Analysis

The investigation team began collecting specimens and epidemiological data on December 8, 2024. Recruitment of participants was based on clinical attendance, following a first-come, first-served basis. Samples were collected before treatment began, spanning epidemiological weeks 49 through 51 of 2024. Notably, no statistical methods were applied to the collected data.

Laboratory Procedures

A wide array of laboratory tests were employed to identify potential pathogens. These included rapid diagnostic tests (RDTs) for P. Falciparum malaria, blood cultures, and molecular testing using multiple PCR assays. Samples were shipped in three batches to the INRB in Kinshasa, DRC, on December 7, 13, and 15, 2024, with varying storage methods to maintain sample integrity.

Advanced Molecular Techniques

Researchers utilized advanced techniques like metagenomic sequencing to identify known and potentially novel pathogens. This involved processing samples with the BioFire FilmArray System, as well as employing the Twist Comprehensive Viral Research (CVR) Panel. Bioinformatics analysis was conducted using pipelines like atavide lite and wf-metagenomics, leveraging computational resources at the Setonix Supercomputer.

Expert Insight: The use of multiple, advanced diagnostic techniques – from traditional blood cultures to cutting-edge metagenomic sequencing – underscores the complexity of identifying the cause of outbreaks in resource-limited settings and the importance of a multi-faceted approach.

Collaboration and Ethical Conduct

The investigation emphasized close collaboration with local partners throughout all phases, from study design to data ownership. Capacity-building activities, including training for researchers in Panzi and Kinshasa, were also implemented. The research adhered to national regulations and prioritized the well-being of participants, with no identified risks of stigmatization or discrimination.

Frequently Asked Questions

What symptoms were used to define a suspected case?

Individuals living in Panzi from September to December 2024 who presented to a health center with at least one of the following symptoms were considered suspected cases: fever, cough, fatigue, runny nose with or without chills, headache, dyspnea, malnutrition, pallor, or body aches.

How were samples transported to the laboratory?

Samples were shipped to the INRB in Kinshasa in three batches, kept in transport boxes with cold accumulators. Blood samples were kept cold, while some specimens were stored in liquid nitrogen.

What types of molecular tests were used in the investigation?

Researchers used the CDC Influenza SARS-CoV-2 multiplex real-time PCR assay, the FTD Respiratory Pathogens 21 assay, the BioFire Global Fever Panel, the Biofire BioThreat panel, and TaqMan Microbial Array card, along with metagenomic sequencing.

Given the comprehensive data collection and advanced laboratory techniques employed, further analysis of the collected samples could potentially reveal the causative agent of this outbreak and inform future public health interventions.