After the 2023 Equatorial Guinea Marburg virus (MARV) outbreak, surveillance of 181 persons in southern Cameroon detected MARV antibodies in 3 persons and Ebola virus antibodies in 7. Testing of 289 captured bats, including 158 Rousettus aegyptiacus bats, did not detect MARV RNA. Enhanced surveillance for regional filovirus spillover risks is warranted.

The incidence of autochthonous arboviral infections in mainland France, particularly in the southern region of Occitanie, is increasing. Despite mandatory reporting, non-specific symptoms and asymptomatic cases likely lead to case underestimation. This study aimed to assess dengue seroprevalence for the first time in the general population consulting in routine general practice in southern mainland France. We conducted a multicenter cross-sectional seroepidemiologic survey in the adult population consulting in routine care in three departments (Hérault, Gard, Pyrénées-Orientales) of Occitanie. Patients completed a brief questionnaire, and two capillary blood drops were collected on filter paper. Multiplex serology (Luminex®) was used to detect IgG antibodies against the four DENV serotypes. A total of 629 participants were enrolled between March and May 2024, with a median age of 54 years, of whom 67 % were female. Nine patients tested positive for anti-DENV IgG, yielding an overall prevalence of 1.43 % (95 %CI: 0.75-2.69), including two participants with no travel history. These findings, although they should be interpreted with caution due to the potential for false positives and cross-reactivity, highlight the possibility of low-level dengue circulation in southern France escaping the surveillance system. This pilot study highlights the need to enhance the arboviral surveillance networks in response to the increasing arboviral threat in France.

This study aimed to assess mpox virus (MPXV) seroprevalence in South Kivu, Democratic Republic of the Congo, where a large mpox outbreak started at the end of 2023. A community-based surveys was conducted in urban (April-May 2023) and rural (July-August 2024) areas and a multiplex serological assay to detect anti-IgG against MPXV has been used. MPXV seroprevalence was 3.3% in the urban survey (n = 1174) and 8.3% in the rural survey (n = 981), with differences according to health zone (P = .004) after the mpox outbreak. This study shows temporal and geographic variation in MPXV seroprevalence and suggest potential spread of mpox in the general population in South Kivu.

Abstract The recent MPXV epidemic across Africa revealed extensive viral diversity and complex transmission dynamics, prompting a continent-wide genomic investigation. We analysed 3,450 high-quality MPXV virus whole genomes from 24 African Union Member States, revealing the complex and concurrent circulation of Sub-clades Ia, Ib, IIa, and IIb. Subclade Ia showed high levels of virus diversity in reservoir hosts in Central Africa, detected through zoonotic transmission and some sustained human outbreak lastly detected. In contrast, Clade Ib exhibited signatures of sustained human-to-human transmission across Eastern and Southern Africa. Clade IIa remains largely zoonotic in West Africa. Like Ia, IIb shows continued zoonotic transmission, and sustained human outbreak linked to lineage G1 and G2 circulation. Phylogeographic analyses revealed frequent cross-border transmission and interconnectedness, which was aligned with both human mobility corridors and international boundaries. For instance, the Democratic Republic of the Congo or Sierra Leone seems to emerge as a source of regional exportation, while the Cameroon–Nigeria, CAR-Cameroon or CAR-DRC interfaces reflected ongoing cross-border zoonotic spillovers. These findings underscore the need for harmonised genomic surveillance, APOBEC3-aware triage, and integrated One Health strategies to prevent local outbreaks from escalating into regional epidemics and to inform vaccine deployment and public health preparedness.

Understanding the serological landscape of endemic and emergent coronaviruses is critical to interpreting early-pandemic immune responses and evaluating hypotheses of cross-reactivity. It was proposed that prior exposure to endemic coronaviruses could affect susceptibility or shape symptom severity through cross-reactive antibody responses. However, little was known about baseline coronavirus seroprevalence in many global regions, including Abidjan, Côte d’Ivoire. Characterizing this landscape provides key insights into early pandemic immunity and the potential influence of prior coronavirus exposures on SARS-CoV-2 immune response. Here, we probe this using data from syndromic surveillance in Abidjan, Côte d’Ivoire, collected between September 2020 and July 2021. We quantified IgG antibody levels to both spike and nucleocapsid proteins for emergent coronaviruses (SARS-CoV-1, SARS-CoV-2, and MERS-CoV) and endemic coronaviruses (HKU1, OC43, NL63 and 229E) using high-throughput multiplex bead assay. Samples were collected from SARS-CoV-2 negative healthcare workers (N = 202) and SARS-CoV-2 positive patients (N = 207). SARS-CoV-2 positive patients returned for repeat sampling at day 28 (N = 131). SARS-CoV-2 negative healthcare workers had higher SARS-CoV-1 seropositivity [0.27 (CI: 0.21–0.33) vs. 0.18 (CI: 0.13–0.24)] and SARS-CoV-2 seropositivity [0.52 (CI: 0.46–0.59) vs. 0.37 (CI: 0.31–0.44)] than SARS-CoV-2 positive patients. There were no significant differences among endemic coronaviruses between the healthcare workers and patients. Among the endemic coronaviruses, seropositivity was highest for 229E at 0.96 (95

Zoonotic diseases have significant implications for public health. Increasing knowledge and stakeholder engagement is therefore essential to ensure their early detection. This study assessed the short-term effects of the ALERT serious game on stakeholders involved in disease surveillance in Cameroon. ALERT is a collaborative serious board game focusing on best practices in surveillance, based on the One Health approach. This study was conducted in the Campo district in southern Cameroon. It involved subprefectural technical staff from various sectors (livestock, public health and wildlife), as well as staff members from the Campo subprefecture and community stakeholders. The general evaluation framework used here is based on the New World Kirkpatrick Model, a conceptual framework commonly used to evaluate training programs that is also suitable for assessing the effects of games. Participants’ reactions during and after the game and the degree of learning were evaluated, with data collected using participatory and qualitative methods. Based on the two criteria assessed, the evaluation indicated participant satisfaction with the game while also highlighting several limitations. It also demonstrated that participants enhanced their understanding of zoonotic diseases and the associated surveillance challenges after playing the game. Additionally, participants showed a stronger appreciation for cross-sector collaboration and identified specific actions to strengthen such collaboration at the district level. New stakeholders were identified and integrated into the proposed community-based surveillance system and the criteria for evaluating its effective operation. These findings underscore the need to evaluate post-game actions and to co-construct support to ensure their effective translation into practice.

Background:The ongoing Bundibugyo virus disease (BDBV) outbreak in Central Africa highlights the absence of approved vaccines specifically targeting BDBV. Whether licensed Zaire ebolavirus (EBOV) vaccines induce cross-reactive immunity against BDBV remains largely unknown. Methods:We performed an immunogenicity analysis using serum samples from participants enrolled in the PREVAC randomized clinical trial evaluating licensed Ebola vaccine strategies in West Africa. Samples collected at day 28 (D28) and month 3 (M3) following vaccination with rVSVΔG-ZEBOV-GP or Ad26.ZEBOV/MVA-BN-Filo were assessed using a multiplex Luminex assay against glycoproteins from multiple filoviruses, including EBOV Kikwit, EBOV Mayinga, BDBV, Sudan virus, Reston virus, and Marburg virus. Results:A total of 179 samples were analysed. Detectable cross-reactive antibody responses against BDBV were observed across vaccine groups, timepoints, and age categories. However, BDBV responses remained substantially lower than homologous EBOV responses. In rVSV recipients, median BDBV responses (net MFI) reached 282 (IQR 164-644) at D28 compared with 1788 (832-3311) against the homologous Kikwit antigen. Similar patterns were observed following rVSV booster vaccination and Ad26.ZEBOV/MVA-BN-Filo vaccination. The heterologous Ad26/MVA regimen demonstrated increasing BDBV responses between D28 and M3. Conclusions:Licensed EBOV vaccines induced detectable but quantitatively reduced cross-reactive antibody responses against BDBV. Although no direct assessment of vaccine efficacy against BDBV disease was possible, these findings support the plausibility of partial heterologous immunity following EBOV vaccination. In the absence of approved BDBV-specific vaccines, these data support the urgent evaluation of currently available Ebola vaccines during BDBV outbreaks and reinforce the importance of developing broadly protective pan-filovirus vaccines.

On 4 September 2025, the Ministry of Public Health, Hygiene and Social Welfare officially declared the 16th Ebola disease outbreak in the Democratic Republic of the Congo (DRC). This outbreak ended on 1 December 2025 and occurred in Bulape Health Zone, Kasaï Province, an area with limited access to appropriate healthcare facilities and resources. Here, we describe the probable index patient and molecular investigations of samples obtained from six suspected patients from the initial outbreak phase. We identified Orthoebolavirus zairense (EBOV) in five samples from different patients. In addition, we performed whole-genome sequencing and generated four complete EBOV genomes. These genomes form a well-supported phylogenetic cluster with genomes from the 1976 Yambuku/Mayinga outbreak. This study suggests a likely new zoonotic spillover event from an as-yet unidentified natural reservoir. While the close relationship to 1976 EBOV Yambuku/Mayinga genomes is striking, this poses additional challenges on the comprehension of the animal reservoir species. The study reports the emergence of a new Ebola variant in a remote area of Kasai Province, DR Congo. The findings highlight the need for rapid detection and sequencing to better identify variants and quickly respond to outbreaks.

The COVID-19 pandemic raised concerns about SARS-CoV-2 infection in pregnant women, especially regarding pregnancy outcomes and maternal-child health. Despite the limited seroprevalence data in this population category, it is crucial for public health strategies in Africa. Therefore, this study aims to determine the seroprevalence of SARS-CoV-2 in pregnant women attending antenatal consultations (ANC) in Senegal. This is a retrospective serological study using archived plasma samples collected prospectively, ensuring no redundancies, among pregnant women attending ANC, between March and July 2021 during the Delta wave of COVID-19. Plasma samples were stored at -80 °C until analysis for the presence of IgG and IgM antibodies against SARS-CoV-2 using the WANTAI SARS-CoV-2 Ab ELISA (Wantai Biological Pharmacy Enterprise, Beijing), according to the manufacturer’s protocol. Bivariate analysis was conducted to evaluate characteristics associated with seropositivity using JMP® Pro Version 15.0.0 software (SAS Institute Inc., Cary, NC, 1989–2021). For categorical variables with frequencies below 5

Since May 2023, COVID-19 is no longer a Public Health Emergency of International Concern. However, it remains an infection that requires monitoring, especially in the post-emergency context where testing and preventative measures have been abandoned by the population. The objective of this study was therefore to measure the seroprevalence of antibodies against SARS-CoV-2 in Conakry in the post-health emergency period and to identify the associated factors. In January 2024, we conducted a population-based, age-stratified seroprevalence survey in Conakry. We collected demographic and epidemiological information, as well as dried blood spot samples, and tested them for immunoglobulin G (IgG) antibodies to SARS-CoV-2 recombinant nucleocapsid and spike proteins using Luminex technology. Overall, 1018 individuals with a median age of 18 years (IQR: 10–37 years) from 180 households participated in the survey. The overall weighted and age-standardized SARS-CoV-2 IgG seroprevalence against spike and nucleocapsid proteins was 88.9

Mpox has evolved into a global public health concern following rapid geographic expansion and altered clinical and epidemiological characteristics. The 2022 outbreak of monkeypox virus (MPXV) marked the first widespread expansion to non-endemic regions, particularly among men who have sex with men (MSM). In the Democratic Republic of the Congo (DRC), where Clade I MPXV is endemic, data on urban exposures are limited. We evaluated serologic evidence of exposure using a four-plex MPXV assay among 1,823 participants from two major DRC cities, Kinshasa and Goma, between April and June 2024. Of these participants, 523 (28.7%) self-identified as MSM, 498 (27.3%) as professional sex workers (SW), 107 (5.9%) as MSM and SW, and 695 (38.1%) as other at-risk individuals. Overall, 2.9% of participants were seroreactive. By subpopulation, 4.8%, 2.1%, and 1.7% of at-risk, MSM, and SW participants were seroreactive (p = 0.0086). Classification tree modelling identified age as the strongest predictor of reactivity, with higher MPXV seroreactivity in older participants. These data provide evidence of mpox seroreactivity prior to sustained human-to-human transmission in urban settings. Understanding exposure dynamics is critical for anticipating re-emergence of mpox in global cities where interpersonal networks may sustain transmission even in the absence of zoonotic spillover.

BACKGROUND:The mpox outbreak in August 2024 in central Africa, together with the mpox pandemic in 2022 associated with the emergence of new viral lineages in urban areas, highlighted that this historically neglected zoonotic tropical disease caused by mpox virus (MPXV) is of public health concern. The majority of mpox infections are of zoonotic origin, but knowledge on the animal reservoir of MPXV is still extremely limited. METHODS:Nonhuman primate (NHP) samples (n = 1571) from 29 different species, collected across Cameroon and the Democratic Republic of the Congo (DRC), were tested for the presence of IgG antibodies with a peptide-based multiplex mpox serological assay. RESULTS:According to stringent or less-stringent cutoff used, 17 to 85 animals (1.1%-5.4%) had antibodies to at least 1 of the 3 peptides used. Seropositive samples were observed in 7 to 15 species, including Cercopithecus sp (C. ascanius, C. cephus, C. mitis, C. nictitans, C. neglectus, C. pogonias), Cercocebus sp (C. torquatus, C. agilis), Colobus sp (C. angolensis, C. guereza), Papio anubis, Lophocebus albigena, Mandrillus sphinx, Allenopithecus nigroviridis, and Pan troglodytes. Mpox seroprevalence was higher in Cameroon than in DRC (1.7%-8.5% vs 0.2%-0.9%; P < .01 to P < .001, respectively). Seroprevalence differed also according to sampling sites. In several sites, more than 1 NHP species was seropositive. Mpox seroprevalence differed, but not significantly, in arboreal (1.2%-5.4%; 15-69/1267), semiterrestrial (1.1%-4.3%; 1-4/92), and terrestrial species (0.5%-5.7%; 1-12/212). CONCLUSIONS:The low overall seroprevalence suggests that NHPs are most likely intermediate hosts and may be infected by other species, including reservoirs. However, they remain a potential source of human infection.

Household transmission studies provided key insights on SARS-CoV-2 transmission in high-income countries but were rarely implemented in Africa. To help fill this gap, we analyzed SARS-CoV-2 seroprevalence studies with a household-based recruitment, focusing on households with ≤7 members, in four Sub-Saharan African cities: Kinshasa (82 households, 370 individuals), Lubumbashi (225 households, 970 individuals), Conakry (149 households, 649 individuals), and Yaoundé (311 households, 1183 individuals), between late 2020 and mid-2021. Using an extended chain-binomial model accounting for missing serology, we estimated both the probability of community-acquired infection and within-household transmission. The proportion infected in the community rose sharply over time, reaching up to 73% by June 2021. Household transmission varied by location, with secondary attack rates ranging from 8.9% to 26.7%, and households accounting for 9% to 28% of infections. Simulations showed that including households with missing serology improved the precision of estimates without introducing bias. Secondary attack rate estimates were consistent with findings from South Africa and slightly lower than global pooled estimates, mostly from high-income settings, suggesting different transmission dynamics in African contexts. Our approach for handling missing serology can improve transmission estimates accuracy.

The accurate measurement of Ebola virus (EBOV)-specific antibody responses is crucial to assessing immunity induced by EBOV infection or vaccination. For this purpose, the Filovirus Animal Nonclinical Group (FANG) anti-EBOV glycoprotein (GP1,2) ELISA is considered the "gold-standard". However, it has limitations such as high repeat-rates and variability, and low throughput. Here, we describe two new alternative assays: a Single-Molecule Assay Planar EBOV GP1,2 ELISA and a multiplexed EBOV GP1,2, EBOV nucleoprotein, and EBOV Viral Protein 40 Luminex assay, and compare these with two versions of the FANG ELISA. Samples were selected from participants receiving vaccine or placebo in a randomized, placebo-controlled, double-blinded study of two EBOV vaccines (PREVAIL 1), and a longitudinal cohort study of Ebola virus disease (EVD) survivors and their close contacts (PREVAIL 3). All four assays were concordant in their measurements of anti-EBOV GP1,2-specific immunoglobulin G responses, allowing for the determination of conversion equations for antibody measurements across assays. In addition, all four showed a similar ability to distinguish vaccine recipients from placebo recipients and EVD survivors from their close contacts. Compared to the FANG assays, the Quanterix and Luminex assays had lower variability, lower repeat rates, and higher throughput, making them good alternatives for future studies.

In May 2026, an outbreak of Ebola disease caused by Bundibugyo virus (BDBV, species Orthoebolavirus bundibugyoense) was declared in the Democratic Republic of the Congo (DRC), with cases originating from DRC and locally transmitted cases reported in Uganda. Bundibugyo virus disease (BVD) outbreaks were previously recorded in 2007-2008 in Bundibugyo District, Uganda, and in 2012 in Isiro, DRC. Here, we generated 22 genomes from samples obtained from individuals with BVD in DRC and Uganda. These genomes form a well-supported phylogenetic cluster separate from BDBV variants associated with the 2007 and 2012 outbreaks, together with evidence for sustained human transmission. This is consistent with the emergence of a new zoonotic spillover event rather than resurgence from previously reported variants. Besides ongoing efforts in strengthening surveillance systems, community engagement, establishing Ebola treatment centers, and developing targeted medical countermeasures; our report advocates to specifically increase decentralized laboratory diagnostics capacity, with pan-Orthoebolavirus assays, including genomic sequencing capacity, for limiting further outbreak expansion, timely detection and control of future outbreaks. A phylogenetic analysis of 22 genomes from the recent Bundibugyo virus outbreak in the Democratic Republic of the Congo and Uganda suggests the outbreak was caused by a new zoonotic spillover event.

Background HIV Viral Load (HIV-VL) and Early Infant Diagnosis (EID) play a pivotal role in the laboratory surveillance, monitoring of HIV/AIDS, and its elimination as a public concern. However, sample rejection due to sample nonconformity (SNC) resulting from inadequate collection, transportation, and management, especially during the pre-analytical phase, negatively affects laboratory performance. This study aimed to characterize errors observed during the pre-analytical phase of HIV-VL and EID testing across national reference laboratories in Cameroon and to identify factors associated with rejection. Methods A descriptive and quantitative study of the nonconformities (NC) identified was collected from 11/01/2024 to 08/12/2024 in seventeen HIV reference laboratories, which constitute the national network of HIV-VL and EID testing coverage. For this study, the number of rejected samples, the reason for rejection, and the type of test ordered were recorded monthly. Results During the study period, 326,885 and 38,354 specimens received for HIV viral load and EID. Of those 12,748 (3.9%) and 2.7% (1,039) were rejected. The SNC analysis indicates the presence of multiple errors or NC in some samples. For HIV viral load, our results indicate that specimen identification errors for viral load were the most common NC (63.14%; n = 8049; P = 0.031), followed by insufficient specimen volume (43.7%; n = 5571; P = 0.049) and quality errors, including hemolyzed specimens (27.8%; n = 3543; P = 0.054), and specimen transport packaging errors (9.1%; n = 1160; P = 0.069). For HIV EID, specimen rejections were primarily attributed to missing or mismatched identification on the request forms (37.12%, n = 386; P = 0.042), sample unavailability (13.4%; n = 139; P = 0.056), and information discrepancies (44.2%; n = 459; P = 0.033). The observed significant rejection rates for both HIV viral load and EID exceeded the established national rejection rate of <2% of errors. Our results suggest that corrective action is critical, along with the establishment of policies to detect and resolve preanalytical errors in Cameroon. Conclusion Our findings highlight the high magnitude of preanalytical errors for HIV-VL and EID tests used in the testing and management of people living with HIV/AIDS in Cameroon. Therefore, the laboratory system should be strengthened to ensure high-quality patient services and support optimization. Suggestions for improvement include distributing a validated specimen-collection manual, creating electronic test-request forms, providing staff training, and regularly on-site supervising the use of available resources, all of which are necessary in this country.

BACKGROUND:Hepatitis E virus (HEV) is a zoonotic pathogen mainly transmitted through contaminated food or water in sub-Saharan countries, highlighting the need for environmental surveillance. This study aimed to assess the burden and molecular characterization of HEV in environmental wastewater. METHOD:A community-based surveillance was conducted in Yaoundé, Cameroon, using untreated wastewater samples collected monthly from January to December 2023 from hospitals, residential sewage systems, markets, and plant watering points. Molecular phylogeny was performed on sequences from the Open Reading Frame 1 region. RESULTS:HEV was detected in 26.4% (19/72) of all sites, with prevalence ranging from 8.3% (1/12) in hospitals to 41.7% (5/12) in residential areas (p = 0.0022). Of the 19 positives, HEV detection was highest in specific residential areas (26.3%) and plant watering points (15.8%). Detection rates were significantly higher during the short dry season (36.8%) and long dry season (31.6%) compared to the short-wet season (21.05%) and long-wet season (10.53%) (p = 0.034). Phylogenetic analysis of the sequenced samples revealed that the detected HEV strains are closely related to Orthohepevirus C genotype C1 previously associated with rodents rather than to the classical human HEV genotypes. This finding raises important questions about possible zoonotic transmission in densely populated urban areas. CONCLUSION:This is the first study to report HEV detection and genetic analysis in wastewater from the Mfoundi Division of Yaoundé, and only the second such report in Cameroon. The presence of HEV in community wastewater, especially from residential and irrigation sites, suggests widespread circulation and potential environmental and foodborne risks. The identification of HEV-C1-like strains highlights the possible role of rodents in transmission. These findings emphasize the importance of integrating wastewater surveillance into public health strategies and call for further research on zoonotic sources through a One Health lens.

Since late 2020, the emergence of variants of concern (VOCs) of SARS-CoV-2 has been of concern to public health, researchers and policymakers. Mutations in the SARS-CoV-2 genome-for which clear evidence is available indicating a significant impact on transmissibility, severity and/or immunity-illustrate the importance of genomic surveillance and monitoring the evolution and geographic spread of novel lineages. Lineage B.1.619 was first detected in Switzerland in January 2021, in international travellers returning from Cameroon. This lineage was subsequently also detected in Rwanda, Belgium, Cameroon, France, and many other countries and is characterised by spike protein amino acid mutations N440K and E484K in the receptor binding domain, which are associated with immune escape and higher infectiousness. In this study, we perform a phylogeographic analysis to track the geographic origin and subsequent dispersal of SARS-CoV-2 lineage B.1.619. We employ a recently developed travel history-aware phylogeographic model, enabling us to incorporate genomic sequences with associated travel information. We estimate that B.1.619 most likely originated in Cameroon, in November 2020. We estimate the influence of the number of air-traffic passengers on the dispersal of B.1.619 but find no significant effect, illustrative of the complex dispersal patterns of SARS-CoV-2 lineages. Finally, we examine the metadata associated with infected Belgian patients and report a wide range of symptoms and medical interventions.

Objective:Data on the impact of coronavirus disease 2019 (COVID-19) in people with HIV (PWH) are lacking in resource-constrained settings. We utilized existing randomized clinical trials (RCTs) on antiretroviral therapies (ART) in HIV-1 infection to conduct a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serosurvey, between January and March 2021, while characterizing participants' features. Design:Cross-sectional serosurvey. Methods:Demographic characteristics, medical history and a serum sample were collected from consenting PWH. Samples were analyzed centrally for immunoglobulin G antibodies to recombinant nucleocapsid and spike proteins derived from SARS-CoV-2 using a Luminex based assay. Results:The 549 participants recruited in 9 sites across Africa had a median age of 40 years (interquartile range, IQR [34-45]); 63.0% (346) were female. All were on ART; 81.8% (449) had an HIV-1 viral load <50 copies/ml, with CD4+ cell count median at 478/mm3 (IQR [320-677]). None had received vaccination against SARS-CoV-2. Forty participants (7.3%) had a prior SARS-CoV-2 PCR testing, of whom 10 were positive (1.8%). Crude SARS-CoV-2 seroprevalence was 36.2% (95% confidence interval (CI) [32.2-40.4]). In the explorative multivariable analysis, comparison of the characteristics of PWH with a positive SARS-CoV-2 serology with those with a negative or indeterminate serology: PWH with a body mass index (BMI) >= 30 kg/m2 were more likely to have a positive serology than those with a BMI <25 (adjusted odds ratio (aOR) = 2.39 [1.48-3.86], P < 0.001); and PWH living in Cameroon were less likely to have a positive serology. Conclusion:This study demonstrates a substantial seroprevalence level of SARS-CoV-2 in PWH in the first quarter of 2021, with a marked disparity with the number of COVID-19 PCR tests reported positive.