Multiplex detection of antibodies to Chikungunya, O'nyong-nyong, Zika, Dengue, West Nile and Usutu viruses in diverse non-human primate species from Cameroon and the Democratic Republic of Congo.

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

Estimation de la densité par comptage des nids des Bonobos (Pan paniscus) dans la région de Bolobo des localités de Nkala et Embirima, République Démocratique du Congo : résultats préliminaires

Le Territoire de Bolobo, Province de Bandundu en R.D. Congo, est situé à 300 km Nord-Ouest de Kinshasa le long du Fleuve Congo. Dans cette étude, nous avons cherché à connaitre la distribution des bonobos, Pan paniscus (Pongidae, Primates), dans leur milieu d’origine de Bolobo. Ainsi, nous avons déterminé les densités des populations de bonobos dans les mosaïques de forêts entrecoupées des savanes dans cette région. Les calculs de densités enregistrés, durant la période du mois de septembre 2008, ont été relativement bas de 0,04 à 0,21 bonobos/km2, par la méthode de comptage des nids sur pied le long des transects, respectivement dans la forêt secondaire de Nkala-MMT (Mbou-Mon-Tour) et la forêt primaire d’Embirima. Le taux de rencontre des nids à Embirima, l’indice kilométrique d’abondance (IKA) a été de 49,11 nids/km, plus élevé que celui de Nkala-MMT avec un IKA de 12,71 nids/km. Ces données confirment que les bonobos sont répartis de manière très éparse et irrégulière. De telles observations peuvent permettre d’établir un programme adéquat de surveillance pour la sauvegarde et la protection de l’espèce.The Territory of Bolobo (Province of Bandundu, R.D. Congo) is located at 300 km in the North-West of Kinshasa, along the Congo River. In this study, we researched the bonobos distribution, Pan paniscus (Pongidae, Primates), in their origin location from Bolobo. We determined the densities of the populations of bonobos in the mosaics of forests intersected with savannas in this area. The densities estimated during September 2008, have been relatively low 0.04 to 0.21 bonobos/km2, by the method of nests counting, along the transects lines, respectively for the secondary forest of Nkala-MMT (Mbou-Mon-Tour) and the primary forest of Embirima. Concerning the rate of bonobo nests expressed as their kilometric index of abundance (KIA) it has been of 49.11 nests/km in Embirima, higher than that of Nkala-MMT where the KIA was of 12.71 nests/km. These data show that bonobos are distributed in a very scattered and irregular way. These observations may help establishing an adequate program of survey for the saving and the protection of the specie

Evaluation de la densité relative et premières observations sur les groupes sociaux des bonobos (Pan paniscus) dans la forêt de Bolobo (Site Mbou-Mon-Tour), R.D.Congo

Malgré leur protection officielle par les lois Congolaises et internationales - Classe A de la convention Africaine sur la conservation de la nature et des ressources naturelles (1968); Convention de Washington (1973); Appendice I de CITES (1976-2013); IUCN Red List (2008) - les bonobos sont extrêmement menacés, et de ce fait de plus en plus en disparition. Ici, nous présentons un aperçu de la population de bonobos dans la forêt mosaïque de Bolobo, site de l’ONG Mbou-mon-Tour, Localité de Nkala, Secteur de Mbe, Territoire de Bolobo, District des Plateaux, Province de Bandundu, en République Démocratique du Congo, étant le plus ouest des sites recensés à présent. Le recensement des bonobos s’est basé sur une évaluation de leur densité ainsi que des observations de leurs groupes sociaux obtenus entre Décembre 2007 et Mars 2008 dans le cadre d’un mémoire de licence en Biologie à la Faculté des Sciences de l’Université de Kinshasa. A l’aide de la méthode des transects linéaires, nous avons examiné 14 km couvrant une superficie de 40 km2. Les résultats obtenus suivant le programme DISTANCE 5.0) ont donné une densité de bonobos de 1,059 ind/ km² que nous comparons avec notre inventaire direct des groupes sociaux donnant une moyenne de 1,092 individus/km². En parallèle, nous avons recensés l'alimentation collectionnant 143 plantes alimentaires. Pour la période sous observation nous avons déterminé 16 espèces, regroupées en 14 genres et 11 familles. Nous positionnons la densité de population parmi ceux obtenus des sites bonobos de long terme, Wamba, Lomako et LuiKotale. Nous avons constaté que Bolobo présente une carence en fruits (37.76% des fruits) comparativement à 59% trouvé à Wamba par Kano, et discutons nos données devant l’arrière-plan de la qualité des habitats donnés

Erratum to: High Prevalences and a Wide Genetic Diversity of Simian Retroviruses in Non-human Primate Bushmeat in Rural Areas of the Democratic Republic of Congo

International audienc

Investigating the Circulation of Ebola Viruses in Bats during the Ebola Virus Disease Outbreaks in the Equateur and North Kivu Provinces of the Democratic Republic of Congo from 2018

International audienceWith 12 of the 31 outbreaks, the Democratic Republic of Congo (DRC) is highly affected by Ebolavirus disease (EVD). To better understand the role of bats in the ecology of Ebola viruses, we conducted surveys in bats during two recent EVD outbreaks and in two areas with previous outbreaks. Dried blood spots were tested for antibodies to ebolaviruses and oral and rectal swabs were screened for the presence of filovirus using a broadly reactive semi-nested RT-PCR. Between 2018 and 2020, 892 (88.6%) frugivorous and 115 (11.4%) insectivorous bats were collected. Overall, 11/925 (1.2%) to 100/925 (10.8%) bats showed antibodies to at least one Ebolavirus antigen depending on the positivity criteria. Antibodies were detected in fruit bats from the four sites and from species previously documented to harbor Ebola antibodies or RNA. We tested for the first time a large number of bats during ongoing EVD outbreaks in DRC, but no viral RNA was detected in the 676 sampled bats. Our study illustrates the difficulty to document the role of bats as a source of Ebolaviruses as they might clear quickly the virus. Given the increasing frequency of EVD outbreaks, more studies on the animal reservoir are urgently needed

Extensive serological survey of multiple African non-human primate species reveals low prevalence of Immunoglobulin G antibodies to four Ebola virus species

International audienceBats are considered a reservoir species for Ebola viruses, but nonhuman primates (NHPs) have represented a source of infection in several outbreaks in humans. Here we report serological screening of blood or fecal samples from monkeys (n = 2322) and apes (n = 2327). Thirty-six NHP species from Cameroon, Democratic Republic of the Congo, and Ivory Coast were tested with a sensitive and specific Luminex-based assay for immunoglobulin G antibodies to 4 Ebola virus species. Using the simultaneous presence of antibodies to nucleoproteins and glycoproteins to define positivity, we showed that specific Ebola virus antibodies are not widespread among NHPs. Only 1 mustached monkey (Cercopithecus cephus) from Cameroon was positive for Sudan ebolavirus. These observations support that NHPs are most likely intermediate hosts for Ebola viruses. With the increasing frequency of Ebola outbreaks, it is crucial to identify the animal reservoir and understand the ecology of Ebola viruses to inform disease control

Extensive Survey and Analysis of Factors Associated with Presence of Antibodies to Orthoebolaviruses in Bats from West and Central Africa

The seroprevalence to orthoebolaviruses was studied in 9594 bats (5972 frugivorous and 3622 insectivorous) from Cameroon, the Democratic Republic of Congo (DRC) and Guinea, with a Luminex-based serological assay including recombinant antigens of four orthoebolavirus species. Seroprevalence is expressed as a range according to different cut-off calculations. Between 6.1% and 18.9% bat samples reacted with at least one orthoebolavirus antigen; the highest reactivity was seen with Glycoprotein (GP) antigens. Seroprevalence varied per species and was higher in frugivorous than insectivorous bats; 9.1–27.5% versus 1.3–4.6%, respectively. Seroprevalence in male (13.5%) and female (14.4%) bats was only slightly different and was higher in adults (14.9%) versus juveniles (9.4%) (p p < 0.001). Our data suggest orthoebolavirus circulation is highest in young bats. More long-term studies are needed to identify birthing pulses for the different bat species in diverse geographic regions and to increase the chances of detecting viral RNA in order to document the genetic diversity of filoviruses in bats and their pathogenic potential for humans. Frugivorous bats seem more likely to be reservoirs of orthoebolaviruses, but the role of insectivorous bats has also to be further examined