Precipitation and vegetation shape patterns of genomic and craniometric variation in the central African rodent Praomys misonnei.

Predicting species' capacity to respond to climate change is an essential first step in developing effective conservation strategies. However, conservation prioritization schemes rarely take evolutionary potential into account. Ecotones provide important opportunities for diversifying selection and may thus constitute reservoirs of standing variation, increasing the capacity for future adaptation. Here, we map patterns of environmentally associated genomic and craniometric variation in the central African rodent Praomys misonnei to identify areas with the greatest turnover in genomic composition. We also project patterns of environmentally associated genomic variation under future climate change scenarios to determine where populations may be under the greatest pressure to adapt. While precipitation gradients influence both genomic and craniometric variation, vegetation structure is also an important determinant of craniometric variation. Areas of elevated environmentally associated genomic and craniometric variation overlap with zones of rapid ecological transition underlining their importance as reservoirs of evolutionary potential. We also find that populations in the Sanaga river basin, central Cameroon and coastal Gabon are likely to be under the greatest pressure from climate change. Lastly, we make specific conservation recommendations on how to protect zones of high evolutionary potential and identify areas where populations may be the most susceptible to climate change.

Factors associated with adherence to ARV treatment in people living with HIV/AIDS in a rural area (Koula-Moutou) in East Gabon.

The goal of this study was to evaluate the impact of socio-clinical factors on adherence to antiretroviral treatment in people living with HIV/AIDS in Koula-Moutou (a rural area of Gabon). Two adherence assessment methods based on patient declaration and compliance with pharmacy visits were used to determine qualitative and quantitative aspects of adherence to antiretroviral therapy (ART). The quantitative (82.2%) and qualitative (79.5%) adherences to ART declared by patients were higher than those obtained through pharmacy visit assessment methods (15.8% and 45.2%, respectively). Moreover, the declarative and pharmacy visit compliance methods showed fair agreement (quantitative Kappa = 0.317; qualitative Kappa = 0.311). A better quantitative or qualitative declarative adherence was associated with a lower level of education (P = 0.05 and P = 0.025 respectively). This study reported for the first time the factors influencing adherence to ART in a rural area of East Gabon. We recommend further investigations in a large cohort to better assess the impact of socio-clinical factors on ART adherence in a vulnerable group of patients.

Factors associated with adherence to ARV treatment in people living with HIV/AIDS in a rural area (Koula-Moutou) in East Gabon

The goal of this study was to evaluate the impact of socio-clinical factors on adherence to antiretroviral treatment in people living with HIV/AIDS in Koula-Moutou (a rural area of Gabon). Two adherence assessment methods based on patient declaration and compliance with pharmacy visits were used to determine qualitative and quantitative aspects of adherence to antiretroviral therapy (ART). The quantitative (82.2%) and qualitative (79.5%) adherences to ART declared by patients were higher than those obtained through pharmacy visit assessment methods (15.8% and 45.2%, respectively). Moreover, the declarative and pharmacy visit compliance methods showed fair agreement (quantitative Kappa = 0.317; qualitative Kappa = 0.311). A better quantitative or qualitative declarative adherence was associated with a lower level of education (P = 0.05 and P = 0.025 respectively). This study reported for the first time the factors influencing adherence to ART in a rural area of East Gabon. We recommend further investigations in a large cohort to better assess the impact of socio-clinical factors on ART adherence in a vulnerable group of patients

Evaluating the role of Pleistocene refugia, rivers and environmental variation in the diversification of central African duikers (genera Cephalophus and Philantomba).

BACKGROUND: This study aims to assess the role that Pleistocene refugia, rivers and local habitat conditions may have played in the evolutionary diversification of three central African duiker species (Cephalophus dorsalis, C. callipygus and Philantomba monticola). Genetic data from geo-referenced feces were collected from a wide range of sites across Central Africa. Historical patterns of population genetic structure were assessed using a ~ 650 bp fragment of the mitochondrial control region and contemporary patterns of genetic differentiation were evaluated using 12 polymorphic microsatellite loci. RESULTS: Mitochondrial analyses revealed that populations of C. callipygus and P. monticola in the Gulf of Guinea refugium are distinct from other populations in west central Africa. All three species exhibit signatures of past population expansion across much of the study area consistent with a history of postglacial expansion. There was no strong evidence for a riverine barrier effect in any of the three species, suggesting that duikers can readily cross major rivers. Generalized dissimilarity models (GDM) showed that environmental variation explains most of the nuclear genetic differentiation in both C. callipygus and P. monticola. The forest-savanna transition across central Cameroon and the Plateaux Batéké region in southeastern Gabon show the highest environmentally-associated turnover in genetic variability. A pattern of genetic differentiation was also evident between the coast and forest interior that may reflect differences in precipitation and/or vegetation. CONCLUSIONS: Findings from this study highlight the historical impact of Pleistocene fragmentation and current influence of environmental variation on genetic structure in duikers. Conservation efforts should therefore target areas that harbor as much environmentally-associated genetic variation as possible in order to maximize species' capacity to adapt to environmental change.

Bio-efficacy of medicinal plants used for the management of diabetes mellitus in Gabon: An ethnopharmacological approach.

BACKGROUND/AIM: People suffering of diabetes increased significantly worldwide. Population, in Sub-Saharan Africa and mainly in Gabon, rely on medicinal plants to manage diabetes, as well in rural as in urban areas. This study aimed to survey a wide range of Gabonese plants for their antidiabetic activity. MATERIALS AND METHODS: This study focused on the identification of medicinal plants used in the local treatment of diabetes mellitus. Ethnobotanical investigations were carried out in rural and urban areas of three provinces of Gabon using a semi-structured interview. RESULTS: About 50 plant species belonging to 31 families and 50 genera were recorded, a majority of which have been documented previously to have medicinal properties. Most have documented antidiabetic properties with characterized therapeutic chemical compounds. Of the plant parts used for treatment, stem barks were employed most frequently (50%), followed by leaves (26%); the remaining 24% comprised roots, fibers, fruit, bulbs, flowers, rhizom, skin, and stem. Regarding the mode of preparation, decoction was the most widely used (58%), followed by maceration (18%) and infusion (14%). Almost all the plant products were administered orally (98%). CONCLUSIONS: Taken in concert, this study highlights the possibility of exploiting traditional knowledge of specific medicinal plants for the inexpensive treatment and management of diabetes.

Patterns and risk factors of birth defects in rural areas of south-eastern Gabon.

Within the context of high neonatal mortality in sub-Saharan Africa, a retrospective study was conducted on the prevalence of congenital malformations and the association between maternal risk factors and birth defects in rural populations of south-eastern Gabon. Two populations were studied: a group of 3500 births recorded in rural area (Koula-Moutou) and a second group of 4212 births in a semi-rural area (Franceville) in Gabon. Our data showed an increasing prevalence in congenital anomalies from rural to urban areas (P < 0.001). Maternal risk factors such as age > 35 years, multiparity and employment status were significantly associated with the levels of stillbirth. Together with abortions and stillbirths, congenital malformations require strong monitoring in rural and urban areas of sub-Saharan Africa.

Genotyping of CCR5 gene, CCR2b and SDF1 variants related to HIV-1 infection in Gabonese subjects.

OBJECTIVE: Given the magnitude of the HIV epidemic infection, many viral and human factors were analyzed, and the most decisive was the variant CCR5-Δ32. The presence of a low HIV prevalence (1.8%) in Gabon in the 1990s, compared to neighboring countries, represents a paradox that led us to search for viral and human genetic variants in this country. In this study, only variants of coreceptors and chemokines were investigated. METHODS: Variants of the coding region of the CCR5 gene were analyzed by denaturing gradient gel electrophoresis, and then variants of SDF1 and CCR2b were determined by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: Four rare variants of the CCR5 coreceptor were found, while CCR5-Δ32 and CCR5m303 variants were not found. No association with CCR2b-V64I (17%) and SDF1-3'A (2%) variants was determined in relation to HIV-1 infection in Gabonese patients. CONCLUSION: The paradox of HIV seroprevalence in Gabon, which ended in the 2000s, was not caused by human genetic variants but rather by environmental factors.

Effects of storage type and time on DNA amplification success in tropical ungulate faeces.

The present study compares the effect of three storage media (silica, RNAlater®, ethanol) and time to extraction (1 week, 1 month and 3 months) on mitochondrial and nuclear marker amplification success in faecal DNA extracts from a sympatric community of small to medium-sized Central African forest ungulates (genera Cephalophus, Tragelaphus, Hyemoschus). The effect of storage type and time on nuclear DNA concentrations, genotyping errors and percentage recovery of consensus genotypes was also examined. Regardless of storage method, mitochondrial and nuclear amplification success was high in DNA extracted within the first week after collection. Over longer storage periods, RNAlater yielded better amplification success rates in the mitochondrial assay. However, samples stored on silica showed (i) highest nuclear DNA concentrations, (ii) best microsatellite genotyping success, (iii) lowest genotyping errors, and (iv) greatest percentage recovery of the consensus genotype. The quantity of nuclear DNA was generally a good predictor of microsatellite performance with 83% amplification success or greater achieved with sample DNA concentrations of ≥ 50 pg/µL. If faecal DNA samples are to be used for nuclear microsatellite analyses, we recommend silica as the best storage method. However, for maximum mitochondrial amplification success, RNAlater appears to be the best storage medium. In contrast, ethanol appeared inferior to the other two methods examined here and should not be used to store tropical ungulate faeces. Regardless of storage method, samples should be extracted as soon as possible after collection to ensure optimal recovery of DNA.