Polio-associated paralysis is one of the diseases under national surveillance in the Democratic Republic of the Congo (DRC). Although it has become relatively rare due to control measures, non-polio paralysis cases are still reported and constitute a real problem, especially for etiological diagnosis, which is necessary for better management and response. From September 2022 to April 2023, we investigated acute flaccid paralysis (AFP) cases in Kinshasa following an alert from the Provincial Division of Health. All suspected cases and their close contacts were investigated and sampled. Among the 57 sampled patients, 21 (36.8%) were suspects, and 36 (63.2%) were contacts. We performed several etiological tests available in the laboratory, targeting viruses, including Poliovirus, Influenza virus, SARS-CoV-2, Enterovirus, and arboviruses. No virus material was detected, but the serological test (ELISA) detected antibodies against Chikungunya Virus, i.e., 47.4% (27/57) for IgM and 22.8% (13/57) for IgG. Among suspected cases, we detected 33.3% (7/21) with anti-Chikungunya IgM and 14.3% (3/21) of anti-Chikungunya IgG. These results highlight the importance of enhancing the epidemiological surveillance of Chikungunya.

Background: Environmental surveillance (ES) of wastewater was introduced by the Global Polio Eradication Initiative (GPEI) to improve the sensitivity of acute flaccid paralysis (AFP) surveillance. In the Democratic Republic of the Congo (DRC), ES for poliovirus has been implemented since 2017. This study assessed its sensitivity and productivity. Methods: A retrospective descriptive study using ES for poliovirus data collected in the DRC between September 2017 and June 2025. Wastewater samples were analyzed at the National Institute for Biomedical Research (INRB), using a standardized algorithm that included concentration, cell culture, real-time reverse transcription polymerase chain reaction (rRT-PCR), and VP1 sequencing. Site sensitivity was assessed by productivity, defined as a viral isolation rate ≥ 50%. Results: A total of 2491 wastewater samples were collected. ES expanded from 6 sites in 3 provinces to 27 sites across 8 provinces. Overall site productivity was 33.9% (846/2491 cultures positive for enteroviruses), showing significant variability between sites and over time, which sometimes led to site closures. Non-polio enteroviruses were the most commonly isolated viruses. Among poliovirus isolates, Sabin-like strains (types 1, 2, and 3), novel oral poliovirus vaccine type 2 (nOPV2), and vaccine-derived poliovirus type 2 (VDPV2) were identified, with VDPV2 representing 13.1%. No wild poliovirus was detected. Conclusion: ES for poliovirus has expanded in the DRC, helping detect vaccine-derived poliovirus circulation and confirming the absence of wild poliovirus. Despite ongoing operational and logistical challenges causing fluctuations in site productivity, this study emphasizes the vital role of ES as a supplement to AFP surveillance.

Seroprevalence surveys constitute a critical tool for estimating population exposure to infectious agents, particularly during public health emergencies. In the context of the coronavirus disease 2019 (COVID-19) pandemic, such surveys revealed that the circulation of Severe Acute Respiratory Syndrome Coronavirus 2 in Africa had been largely underestimated. The validity of these surveys, however, depends not only on the reliability of diagnostic tests but also on operational conditions, which are frequently challenged by fear, misinformation, and logistical constraints. In the Democratic Republic of the Congo, the National Institute of Biomedical Research conducted two seroprevalence surveys in Kinshasa in 2020 on behalf the project “Appui à la Riposte Africaine à l’Epidémie de COVID-19” (ARIACOV). This study described the challenges encountered and the adaptive strategies employed during these surveys, in order to improve future investigations. The study population comprised 41 eligible field workers who participated in the 2020 ARIACOV seroprevalence surveys in Kinshasa, including 28 interviewers and 13 specimen collectors. Of these, 24 individuals (16 interviewers and 8 specimen collectors) initially confirmed their participation. Ultimately, 15 participants took part in the focus group discussions, comprising 11 interviewers (39.3% of the 28 eligible interviewers) and 4 specimen collectors (30.8% of the 13 eligible specimen collectors). We collected data through two focus groups held in a single session, using a pre-tested semi-structured guide. Discussions were audio-recorded and complemented by observational notes until empirical saturation was achieved. We applied deductive thematic analysis, following Braun and Clarke’s framework, to three predefined domains: transportation, survey procedures, and sample management. The application of systematic manual coding, combined with researcher triangulation, reinforced the rigor and enhanced the credibility of the findings. The findings highlighted community mistrust, driven by rumors, apprehension regarding blood collection, financial suspicions, and inadequate communication. In addition, logistical and transportation challenges significantly constrained survey feasibility. Nonetheless, a range of adaptive strategies were implemented, enabling the successful conduct of the surveys despite the pandemic context and limited resources. The participants’ narratives suggest that strengthening field workers’ training, improving transparency, and working alongside community health workers could contribute to enhance the effectiveness of serological surveys during health crises in resource-constrained environments.