Dynamique de croissance et taux de mortalité de Rhizophora spp. dans les mangroves de l'estuaire du Rio del Rey: Site de Bamusso (Sud-Ouest Cameroun)

Objectifs : L’objectif des présents travaux est de clarifier le stock du peuplement de Rhizophora ssp. du site par la détermination de ses paramètres de structure spatiale et d'évaluer sa croissance annuelle.Méthodologie et résultats : La méthode d'étude est celle des transects. Deux transects de 100mx10m distantes de 5km orientés WNW-ESE et perpendiculaires au principal chenal ont été établis au hasard .Chaque transect était subdivisé en trois placettes de 20mx10m et chaque placettes scindé en deux sous placettes de 20mx5m. Les mesures (Diamètre et hauteur) ont été effectuées à l'intérieur de chaque sous placette pendant trois campagnes (2009, 2012, 2014). Les résultats montrent que les diamètres moyens pour le transect1(T1) sont de 4,76 ± 0,23cm; 5,09± 0,25cm et 5,43±0,28cm contre 26,53 ± 1,72cm; 24,66 ± 1,90cm et 25,26 ± 1,93cm pour le transect2 (T2) respectivement pour 2009; 2012 et 2014. Les hauteurs moyennes varient de 4,51 ± 0,16 m (2009); 4,74 ± 0,18m (2012) et 4,98 ± 0,2m (2014) pour T1 contre 20,20± 1,22m; 18,86 ± 1,35 m et 19,29 ±1,39m pour T2. L'analyse de la croissance du peuplement montre que les diamètres d'exploitation du bois de la mangrove  affectionnée par les riverains se situent dans l'intervalle (5-30cm). Le test d'ANOVA montre une différence significative (P<0,05) pour les paramètres, de structure et une différence non significative (P>0,05) de la croissance annuelle entre T1 et T2.Conclusion et application des résultats : Cette étude a montré un taux de mortalité relativement faible (m=2,27%) qui présage d'une pression anthropique faible sur cet écosystème. L'étude de la dynamique réalisée permet de recommander ce site dans le processus REDD+ pour le calcul du carbone bleu indispensable dans la lutte contre le phénomène de changement climatique. Mots clés: Transect, Diamètre; Hauteur; Nombre d'individus, BamussoGrowth dynamic and death rate of Rhizophora spp. within mangrove's forest of Rio del Rey estuary (South-West Cameroon)Objective: This study was conducted to clarify the stock of Rhizophora ssp and to assess its growth within the study area.Methodology and results: Transect method was carried out during this study. So, two transects of 100 m in length, 10 m in width and 0.1 ha in area each distance to 5km oriented WNW-ESE and perpendicular to themain channel were established randomly . Each transect was divided in three plots of 20mx10m each and each plot separated in two subplots of 20mx5m each. Measures (Diameter and height) were collected within each subplot during three data collections campaigns (2009,2012,and 2014). The results show that mean diameters of transect1(T1) were 4.76 ± 0.23cm; 5.09± 0.25cm and 5.43±0.28cm to 26.53 ± 1.72cm; 24.66 ± 1.90cm and 25.26 ± 1.93cm for transect2 (T2) respectively in 2009; 2012 et 2014. Mean height values were 4.51 ± 0.16 m (2009); 4.74 ± 0.18m (2012) and 4.98 ± 0.2m (2014) for T1 to 20.20± 1.22m; 18.86 ± 1.35 m and 19.29 ±1.39m for T2. Study of growth show that used diameters of mangrove woods by neighborhood are inside class 5-30cm. The one-way ANOVA test showed a significant difference (P<0.05) for structure  parameters and no significant difference (P>0,05) for annual growth between T1 and T2.Conclusion and application of findings: This study showed a relatively weak annual death rate of trees (m=2.27%) dues to a weak anthropogenic pressure in this ecosystem. This dynamic study will recommend the site to the REDD+ process in order to estimate its blue carbon stock important to fight against climate change.Key words: Transect, Diameter, Height, Number of individuals, Bamuss

Cytotoxic flavonoids and other constituents from the stem bark of Ochna schweinfurthiana

Seven flavonoids, hemerocallone (1), 6,7-dimethoxy-3′,4′-dimethoxyisoflavone (2), amentoflavone (4), agathisflavone (6), cupressuflavone (8), robustaflavone (9) and epicatechin (10), together with three other compounds, lithospermoside (3), β-D- fructofuranosyl-α-D-glucopyranoside (5) and 3β-O-D-glucopyranosyl-β-stigmasterol (7), were isolated from the ethyl acetate extract of the stem bark of Ochna schweinfurthiana F. Hoffm. All the compounds were characterised by spectroscopic and mass spectrometric methods, and by comparison with literature data. Cytotoxicity of the extracts and compounds against cervical adenocarcinoma (HeLa) cells was evaluated by MTT assay. Compounds 4 and 6 exhibited good cytotoxic activity, with IC50 values of 20.7 and 10.0 μM, respectively

Effet du traitement des feuilles de Tithonia diversifolia à la mélasse sur l’ingestion et la digestibilité des chaumes de maïs chez la chèvre naine de Guinée (Capra hircus hircus)

Une étude portant sur l’ingestion et la digestibilité in vivo des chaumes de maïs associés aux feuilles de Tithonia diversifolia non traitées et traitées à 5 ou à 10% de mélasse chez la chèvre naine de Guinée a été menée entre octobre 2012 et janvier 2013. Neuf chèvres naines de Guinée ont été réparties en trois lots de trois animaux chacun et logées dans des cages métaboliques individuelles. Les périodes d’adaptation et de collecte de données étaient respectivement de 10 et 5 jours. Chaque chèvre recevait par jour pendant ces périodes, une ration de 700g de chaumes hachés et de 1200 g de feuilles hachées de T. diversifolia non traitées pour le lot 1 (ration TM0), traitées à 5% de mélasse pour le lot 2 (ration TM5) et traitées à 10% de mélasse pour le lot 3 (ration TM10). Les résultats de cette étude ont montré que l’ingestion des feuilles de T. diversifolia traitées à la mélasse a significativement (p<0,05) amélioré l’ingestion des chaumes et les digestibilités de la MS, de la MO, de la CB et de l’azote des rations. En effet, la digestibilité de l’azote des rations TM5 (67,90%) et TM10 (65,51%) ont été comparables (p>0,05) et significativement supérieures (p<0,05) à celle de la ration TM0 (61,52%). L’utilisation des feuilles de T. diversifolia traitées à la mélasse a permis d’améliorer de manière significative l’ingestion et la digestibilité des chaumes de maïs chez la chèvre naine de Guinée.  Mots clés : Appétibilité, chaumes de maïs, digestibilité, mélasse, petits ruminants, Tithonia diversifoli

Étude ethnobotanique des plantes médicinales commercialisées dans les marchés de la ville de Douala, Cameroun

Objectif: L’objectif de cette étude est d’inventorier et d’identifier les vertus thérapeutiques des plantes médicinales commercialisées dans la ville de Douala (Cameroun).Méthodologie et résultats: Des enquêtes ethnobotaniques ont été conduites de juillet à août 2012, auprès de 54 herboristes dans cinq marchés en utilisant des interviews directes et semi-structurées. L’étude a permis d’identifier 84 espèces réparties en 78 genres et 50 familles dont les plus représentées ont été les Asteraceae (9 espèces), Fabaceae (6 espèces) et Lamiaceae (4 espèces). Les troubles infectieux (66,7 %) et gynécoobstétriques et urologiques ont été majoritairement représentés. La recherche du degré de consensus (ICF) révèle que 3 catégories ont atteint des valeurs élevées : les troubles asthéniques (0,8), dermatologiques (0,6), gynéco-obstétriques et urologiques (0,5).Conclusion et application des résultats: Cette étude montre l’importance des enquêtes ethnobotaniques dans la phytothérapie et les limites des herboristes de la pharmacopée traditionnelle.Mots clés: Ethnobotanique, plantes médicinales commercialisées, maladiesEnglish AbstractObjective: The objective of this study was to make an inventory and to identify therapeutic properties of medicinal plants sold in the city of Douala (Cameroon).Methodology and Results: Ethnobotanical surveys were conducted from July to August 2012 beside 54 herbalists in five markets using direct and semi-structured interviews. The study identified 84 species distributed in 78 genera and 50 families, the most represented were Asteraceae (9 species), Fabaceae (6 species) and Lamiaceae (4 species). Infectious disorders (66.7%) and gyneco-obstetrical and urological disorders were mostly represented. Research on the degree of consensus (ICF) reveals that three categories reached high values: asthenic (0.8), skin (0.6), gyneco-obstetrical and urological (0.5) disorders.Conclusion and applications of results: This study shows the importance of ethnobotanical surveys in herbal medicine and limitations of herbalists of traditional medicine.Keys: Ethnobotany, sold medicinal plants, disease

Effi cacy of a Russian-backbone live attenuated infl uenza vaccine among children in Senegal: a randomised, double-blind, placebo-controlled trial

Background Live attenuated infl uenza vaccines have been shown to signifi cantly reduce infl uenza in diverse populations of children, but no effi cacy studies have been done in resource-poor tropical settings. In Senegal, we assessed the effi cacy and safety of a live attenuated infl uenza vaccine based on Russian-derived master donor viruses and licensed as a single dose. Methods In this double-blind, placebo-controlled, parallel group, single-centre trial done near Niakhar, Senegal, generally healthy children aged 2–5 years were randomly allocated (2:1) to receive a single intranasal dose of masked trivalent live attenuated infl uenza vaccine or placebo. The allocation sequence was computer-generated by PATH with block sizes of three. The manufacturer provided vaccine and placebo in coded vials to preserve blinding. Participants were monitored through the predictable infl uenza season in Senegal for adverse events and signs and symptoms of infl uenza using weekly home visits and surveillance in clinics. The primary outcome was symptomatic laboratoryconfi rmed infl uenza caused by any strain and occurring from 15 days post-vaccination to the end of the study. The primary analysis was per protocol. This study is registered with ClinicalTrials.gov, number NCT01854632. Findings Between May 23, and July 1, 2013, 1761 children were randomly assigned, 1174 to receive live attenuated infl uenza vaccine and 587 to receive placebo. The per-protocol set included 1173 vaccinees and 584 placebo recipients followed up to Dec 20, 2013. Symptomatic infl uenza was laboratory-confi rmed in 210 (18%) of 1173 recipients of live attenuated infl uenza vaccine and 105 (18%) of placebo recipients, giving a vaccine effi cacy of 0·0% (95% CI –26·4 to 20·9). Adverse events were balanced between the study groups. Two girls who had received live attenuated infl uenza vaccine died, one due to anasarca 12 days postvaccination and one due to malnutrition 70 days postvaccination. Interpretation Live attenuated infl uenza vaccine was well tolerated in young children in Senegal, but did not provide protection against infl uenza. Further study in such populations, which might experience extended periods of infl uenza circulation, is warranted

Exposure to Nonhuman Primates in Rural Cameroon

A high percentage of rural villagers are exposed to blood of nonhuman primates and risk acquiring infectious diseases

Feasibility of Early Infant Diagnosis of HIV in Resource-Limited Settings: The ANRS 12140-PEDIACAM Study in Cameroon

BACKGROUND: Early infant diagnosis (EID) of HIV is a key-point for the implementation of early HAART, associated with lower mortality in HIV-infected infants. We evaluated the EID process of HIV according to national recommendations, in urban areas of Cameroon. METHODS/FINDINGS: The ANRS12140-PEDIACAM study is a multisite cohort in which infants born to HIV-infected mothers were included before the 8(th) day of life and followed. Collection of samples for HIV DNA/RNA-PCR was planned at 6 weeks together with routine vaccination. The HIV test result was expected to be available at 10 weeks. A positive or indeterminate test result was confirmed by a second test on a different sample. Systematic HAART was offered to HIV-infected infants identified. The EID process was considered complete if infants were tested and HIV results provided to mothers/family before 7 months of age. During 2007-2009, 1587 mother-infant pairs were included in three referral hospitals; most infants (n = 1423, 89.7%) were tested for HIV, at a median age of 1.5 months (IQR, 1.4-1.6). Among them, 51 (3.6%) were HIV-infected. Overall, 1331 (83.9%) completed the process by returning for the result before 7 months (median age: 2.5 months (IQR, 2.4-3.0)). Incomplete process, that is test not performed, or result of test not provided or provided late to the family, was independently associated with late HIV diagnosis during pregnancy (adjusted odds ratio (aOR) = 1.8, 95%CI: 1.1 to 2.9, p = 0.01), absence of PMTCT prophylaxis (aOR = 2.4, 95%CI: 1.4 to 4.3, p = 0.002), and emergency caesarean section (aOR = 2.5, 95%CI: 1.5 to 4.3, p = 0.001). CONCLUSIONS: In urban areas of Cameroon, HIV-infected women diagnosed sufficiently early during pregnancy opt to benefit from EID whatever their socio-economic, marital or disclosure status. Reduction of non optimal diagnosis process should focus on women with late HIV diagnosis during pregnancy especially if they did not receive any PMTCT, or if complications occurred at delivery

A novel neutralizing human monoclonal antibody broadly abrogates hepatitis C virus infection in vitro and in vivo

Infections with hepatitis C virus (HCV) represent a worldwide health burden and a prophylactic vaccine is still not available. Liver transplantation (LT) is often the only option for patients with HCV-induced end-stage liver disease. However, immediately after transplantation, the liver graft becomes infected by circulating virus, resulting in accelerated progression of liver disease. Although the effi cacy of HCV treatment using direct-acting antivirals has improved significantly, immune compromised LT-patients and patients with advanced liver disease remain difficult to treat. As an alternative approach, interfering with viral entry could prevent infection of the donor liver. We generated a human monoclonal antibody (mAb), designated 2A5, which targets the HCV envelope. The neutralizing activity of mAb 2A5 was assessed using multiple prototype and patient-derived HCV pseudoparticles (HCVpp), cell culture produced HCV (HCVcc), and a human-liver chimeric mouse model. Neutralization levels observed for mAb 2A5 were generally high and mostly superior to those obtained with AP33, a well-characterized HCV-neutralizing monoclonal antibody. Using humanized mice, complete protection was observed after genotype 1a and 4a HCV challenge, while only partial protection was achieved using gt1b and 6a isolates. Epitope mapping revealed that mAb 2A5 binding is conformation-dependent and identified the E2-region spanning amino acids 434 to 446 (epitope II) as the predominant contact domain. Conclusion : mAb 2A5 shows potent anti-HCV neutralizing activity both in vitro and in vivo and could hence represent a valuable candidate to prevent HCV recurrence in LT-patients. In addition, the detailed identification of the neutralizing epitope can be applied for the design of prophylactic HCV vaccines

A global agenda for advancing freshwater biodiversity research

Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation.Peer reviewe