Background: Epidemic arbovirus transmission occurs among humans by mosquito bites and the sylvatic transmission cycles involving non-human primates (NHPs) still exists. However, limited data are available on the extent in NHPs infections and their role. In this study, we have developed and validated a high-throughput serological screening tool to study the circulation of multiple arboviruses that represent a significant threat to human health, in NHPs in Central Africa. Methodology/Principal findings: Recombinant proteins NS1, envelope domain-3 (DIII) for the dengue (DENV), yellow fever (YFV), usutu (USUV), west nile (WNV) and zika (ZIKV) and envelope 2 for the chikungunya (CHIKV) and o'nyong-nyong (ONNV) were coupled to Luminex beads to detect IgG directed against these viruses. Evaluation of test performance was made using 161 human sera of known arboviral status (66 negative and 95 positive). The sensitivity and specificity of each antigen were determined by statistical methods and ROC curves (except for ONNV and USUV). All NS1 antigens (except NS1-YFV), CHIKV-E2 and WNV-DIII had sensitivities and specificities > 95%. For the other DIII antigens, the sensitivity was low, limiting the interest of their use for seroprevalence studies. Few simultaneous reactions were observed between the CHIKV+ samples and the NS1 antigens to the non-CHIKV arboviruses. On the other hand, the DENV+ samples crossed-reacted with NS1 of all the DENV serotypes (1 to 4), as well as with ZIKV, USUV and to a lesser extent with YFV. A total of 3,518 samples of 29 species of NHPs from Cameroon and the Democratic Republic of Congo (DRC) were tested against NS1 (except YFV), E2 (CHIKV/ONNV) and DIII (WNV) antigens. In monkeys (n = 2,100), the global prevalence varied between 2 and 5% for the ten antigens tested. When we stratified by monkey’s biotope, the arboreal species showed the highest reactivity. In monkeys from Cameroon, the highest IgG prevalence were observed against ONNV-E2 and DENV2-NS1 with 3.95% and 3.40% respectively and in DRC, ONNV-E2 (6.63%) and WNV-NS1 (4.42%). Overall prevalence was low in apes (n = 1,418): ranging from 0% for USUV-NS1 to 2.6% for CHIKV-E2. However, a very large disparity was observed among collection site and ape species, e.g. 18% (9/40) and 8.2% (4/49) of gorillas were reactive with CHIKV-E2 or WNV-NS1, respectively in two different sites in Cameroon. Conclusions/Significance: We have developed a serological assay based on Luminex technology, with high specificity and sensitivity for simultaneous detection of antibodies to 10 antigens from 6 different arboviruses. This is the first study that evaluated on a large scale the presence of antibodies to arboviruses in NHPs to evaluate their role in sylvatic cycles. The overall low prevalence (<5%) in more than 3,500 NHPs samples from Cameroon and the DRC does not allow us to affirm that NHP are reservoirs, but rather, intermediate hosts of these viruses.

The majority of patients with acute febrile jaundice (>95%) identified through a yellow fever surveillance program in the Democratic Republic of Congo (DRC) test negative for antibodies against yellow fever virus. However, no etiological investigation has ever been carried out on these patients. Here, we tested for hepatitis A (HAV), hepatitis B (HBV), hepatitis C (HCV), hepatitis D (HDV), and hepatitis E (HEV) viruses, all of which can cause acute febrile jaundice, in patients included in the yellow fever surveillance program in the DRC. On a total of 498 serum samples collected from suspected cases of yellow fever from January 2003 to January 2012, enzyme-linked immunosorbent assay (ELISA) techniques were used to screen for antibodies against HAV (IgM) and HEV (IgM) and for antigens and antibodies against HBV (HBsAg and anti-hepatitis B core protein [HBc] IgM, respectively), HCV, and HDV. Viral loads and genotypes were determined for HBV and HVD. Viral hepatitis serological markers were diagnosed in 218 (43.7%) patients. The seroprevalences were 16.7% for HAV, 24.6% for HBV, 2.3% for HCV, and 10.4% for HEV, and 26.1% of HBV-positive patients were also infected with HDV. Median viral loads were 4.19 × 10 ⁵ IU/ml for HBV (range, 769 to 9.82 × 10 ⁹ IU/ml) and 1.4 × 10 ⁶ IU/ml for HDV (range, 3.1 × 10 ² to 2.9 × 10 ⁸ IU/ml). Genotypes A, E, and D of HBV and genotype 1 of HDV were detected. These high hepatitis prevalence rates highlight the necessity to include screening for hepatitis viruses in the yellow fever surveillance program in the DRC.

Early March 2019, health authorities of Matadi in the Democratic Republic of the Congo alerted a sudden increase in acute fever/arthralgia cases, prompting an outbreak investigation. We collected surveillance data, clinical data, and laboratory specimens from clinical suspects (for CHIKV-PCR/ELISA, malaria RDT), semi-structured interviews with patients/caregivers about perceptions and health seeking behavior, and mosquito sampling (adult/larvae) for CHIKV-PCR and estimation of infestation levels. The investigations confirmed a large CHIKV outbreak that lasted February–June 2019. The total caseload remained unknown due to a lack of systematic surveillance, but one of the two health zones of Matadi notified 2686 suspects. Of the clinical suspects we investigated (n = 220), 83.2% were CHIKV-PCR or IgM positive (acute infection). One patient had an isolated IgG-positive result (while PCR/IgM negative), suggestive of past infection. In total, 15% had acute CHIKV and malaria. Most adult mosquitoes and larvae (>95%) were Aedes albopictus. High infestation levels were noted. CHIKV was detected in 6/11 adult mosquito pools, and in 2/15 of the larvae pools. This latter and the fact that 2/6 of the CHIKV-positive adult pools contained only males suggests transovarial transmission. Interviews revealed that healthcare seeking shifted quickly toward the informal sector and self-medication. Caregivers reported difficulties to differentiate CHIKV, malaria, and other infectious diseases resulting in polypharmacy and high out-of-pocket expenditure. We confirmed a first major CHIKV outbreak in Matadi, with main vector Aedes albopictus. The health sector was ill-prepared for the information, surveillance, and treatment needs for such an explosive outbreak in a CHIKV-naïve population. Better surveillance systems (national level/sentinel sites) and point-of-care diagnostics for arboviruses are needed.

The recent large outbreaks of Ebola virus disease (EVD) in West Africa and the Democratic Republic of the Congo (DRC) have highlighted the need for rapid diagnostic tests to control this disease. In this study, we clinically evaluated a previously developed immunochromatography-based kit, QuickNavi^TM-Ebola. During the 2018 outbreaks in DRC, 928 blood samples from EVD-suspected cases were tested with QuickNavi^TM-Ebola and the WHO-approved GeneXpert. The sensitivity and specificity of QuickNavi^TM-Ebola, estimated by comparing it to GeneXpert-confirmed cases, were 85% (68/80) and 99.8% (846/848), respectively. These results indicate the practical reliability of QuickNavi^TM-Ebola for point-of-care diagnosis of EVD.

La Guinée et la République Démocratique du Congo (RDC) sont deux pays confrontés à des maladies zoonotiques (ré)émergentes, lesquelles représentent de graves menaces pour la santé publique et pour l’économie. Cela renforce l’importance de mettre l'accent sur les approches interdisciplinaires pour la prévention, la détection et l’atténuation des maladies infectieuses afin de mettre en place des systèmes de réponses adéquats. Dans les dernières années, des efforts ont été fournis dans les deux pays pour la conception, la mise en œuvre et la promotion de l’approche “Une Seule Santé” (One Health) qui offre des solutions à l’interface homme-animal-plante-écosystèmes. Cependant, dans ces pays, il n’existe pas une approche systémique “Une Seule Santé” qui soit réellement opérationnelle. Ainsi, cet article vise à faire une analyse comparative des initiatives « One Health » (OH) en Guinée et en RDC. Les résultats suggèrent qu'il existe un engagement fort de la part du gouvernement guinéen à signer un ordre conjoint de collaboration entre les trois départements clés, mais la coopération et la collaboration entre les différents secteurs et disciplines font défaut. En RDC, trois plateformes existent, mais leurs actions ne sont pas coordonnées, ce qui démontre les lacunes dans la vision globale que devrait avoir l’approche OH. Le défi majeur dans ces deux pays est d'adopter une approche holistique pour dépasser les structures et les paradigmes organisationnels et disciplinaires pour développer une véritable coopération entre tous les secteurs directement ou indirectement touchés par les maladies à potentiel épidémique. Guinea and the Democratic Republic of Congo (DRC) are two countries facing (re)emerging zoonotic diseases, which pose serious threats to public health and the economy. This reinforces the importance of emphasizing interdisciplinary approaches for the prevention, detection, and mitigation of infectious diseases to put in place adequate response systems. In recent years, efforts have been made in both countries for the design, implementation, and promotion of the “One Health” (OH) approach which offers solutions at the human-animal-animal-plant-ecosystems interface. However, in these countries, there is no operational OH systemic approach. Thus, this article aims to make a comparative analysis of the OH initiatives in Guinea and the DRC. Findings suggest there is a strong commitment on the part of the government of Guinea to sign a joint order of collaboration between the three key departments, but cooperation and collaboration between different sectors and disciplines is lacking. In the DRC, three platforms exist but are not coordinated, which shows gaps in the overall vision that OH should be in the country. The major challenge in these two countries is to adopt a holistic approach to go beyond organizational and disciplinary structures and paradigms to develop real coordination and cooperation between all the sectors directly or indirectly affected by diseases with epidemic potential.

High SARS-CoV-2 Seroprevalence, DRC