Ground-Truthing Sahelian Greening: Ethnographic and Spatial Evidence from Burkina Faso

Historically, the Sahel of West Africa has been considered synonymous with desertification. In recent decades, however, satellite images reveal patterns of enhanced vegetation termed the “greening of the Sahel.” This greening is well-documented but its mechanisms remain poorly understood. The Sahel is also a region emerging from a 30 year period of reduced rainfall in which several severe droughts occurred. As a response to droughts and land degradation, farmers have rehabilitated thousands of hectares of degraded soils by constructing low barriers of rock through widespread soil and water conservation (SWC) development projects. Remote sensing analyses suggest that these extensive soil conservation projects may explain greening in northern Burkina Faso. This study combines ethnographic fieldwork with the analysis of Geographic Information System (GIS) and remote sensing (RS) data to test whether SWC investments contribute to greening. Ethnographic data reveal a tension between the perceptions of rural producers who feel that their SWC efforts contribute to greening and those of state officials who contend that SWC has only local impacts and that the regional landscape continues to degrade. Our analysis of GIS and RS data suggest that both perspectives are valid but contingent on the particular spatial and temporal scale used for analysis.     

Inventory and abundance of mealybug species in immature and mature cocoa farms in Côte d'Ivoire

From 2013 to 2018, surveys were conducted in counties not previously surveyed in order to determine species of mealybugs present in the cocoa orchard in Côte d'Ivoire as well as their abundance according to the age of cocoa trees. Immature and mature cocoa trees were inspected to hand‐height in 5 and 29 counties infected with Cacao swollen shoot virus (CSSV). In each cocoa farm, mealybugs were searched for on fruits, leaves, flowers, twigs and trunks. Mealybug species were identified, and colonies were counted. Five mealybug species were identified on immature cocoa trees: Ferrisia virgata, Formicococcus njalensis, Planococcus citri, Planococcus kenyae and Pseudococcus longispinus. In addition to these species, four species, Dysmicoccus brevipes, Maconellicoccus hirsutus, Phenacoccus hargreavesi and Pseudococcus jackbeardsleyi were identified on mature cocoa trees. On immature cocoa trees, Fo. Njalensis, Pl. citri and Ps. longispinus comprised were, respectively, 35%, 33% and 19% of colonies, respectively. On mature cocoa trees, Fo. Njalensis and Pl. citri comprised 63.2% and 21.0%, and others species 15.8%. Nevertheless, the abundance of mealybug species varied according to the age of cocoa trees. The preferred organs of mealybugs were pods (74.1%) followed by twigs (13.4%) and flowers (7.4%). Previously, the mealybug Paracoccus burnerae (Brain) was found on Theobroma cacao, which is the first record for this species in Côte d'Ivoire and on this host‐plant.     

Segmental duplication implicated in the genesis of inversion 2Rj of Anopheles gambiae

The malaria vector Anopheles gambiae maintains high levels of inversion polymorphism that facilitate its exploitation of diverse ecological settings across tropical Africa. Molecular characterization of inversion breakpoints is a first step toward understanding the processes that generate and maintain inversions. Here we focused on inversion 2Rj because of its association with the assortatively mating Bamako chromosomal form of An. gambiae, whose distinctive breeding sites are rock pools beside the Niger River in Mali and Guinea. Sequence and computational analysis of 2Rj revealed the same 14.6 kb insertion between both breakpoints, which occurred near but not within predicted genes. Each insertion consists of 5.3 kb terminal inverted repeat arms separated by a 4 kb spacer. The insertions lack coding capacity, and are comprised of degraded remnants of repetitive sequences including class I and II transposable elements. Because of their large size and patchwork composition, and as no other instances of these insertions were identified in the An. gambiae genome, they do not appear to be transposable elements. The 14.6 kb modules inserted at both 2Rj breakpoint junctions represent low copy repeats (LCRs, also called segmental duplications) that are strongly implicated in the recent (approximately 0.4N(e) generations) origin of 2Rj. The LCRs contribute to further genome instability, as demonstrated by an imprecise excision event at the proximal breakpoint of 2Rj in field isolates.     

Estimating the Local Value of Non-Timber Forest Products to Pendjari Biosphere Reserve Dwellers in Benin

Estimating the Local Value of Non-Timber Forest Products to Pendjari Biosphere Reserve Dwellers in Benin. This paper uses an indices method based on participant ranking of species to quantify use–values of Non-Timber Forest Products (NTFPs) and the socio-economic factors that influence these values for people living around the Pendjari Biosphere Reserve in Benin. There were 76 species identified that had a high index value to people. The 10 most valued species were Parkia biglobosa, Adansonia digitata, Vitellaria paradoxa, Tamarindus indica, Lannea microcarpa, Vitex doniana, Hibiscus asper, Melochia corchorifolia, Khaya senegalensis, and Diospyros mespiliformis. Species values were influenced by the vegetative form of the species as well as by the gender of a participant and his/her affiliation to the ethnic group. The study also illustrates that women had a preference for NTFP species with high commercial and nutritional values, while men preferred plants that provide construction material and medicine. Moreover, the ethnic group that historically had more contact and interaction with the vegetation valued NTFPs more than any other group. The difference in value attributed to species by people was also driven by the vertical transmission of ethnobotanical knowledge in the study area. For long-term biodiversity conservation, it will be useful to involve the needs of all of the local communities in the design of a management plan and focus attention on the most important species.     

Strong Gametocytocidal Effect of Methylene Blue-Based Combination Therapy against Falciparum Malaria: A Randomised Controlled Trial

Background

With the availability of new preventive and curative interventions, global malaria control has been strengthened significantly in recent years. Drugs effective in reducing malaria gametocytaemia might contribute to local elimination and possible long-term eradication. We here report on the effects of methylene blue (MB)-based malaria combination therapy on gametocytaemia during a randomised-controlled trial in Burkina Faso.

Methods

An open-label randomised controlled phase II study in 180 children aged 6–10 years with uncomplicated falciparum malaria was conducted in Nouna, north-western Burkina Faso. Children were randomised to MB–artesunate (AS), MB–amodiaquine (AQ), and AS-AQ (local standard of care). Overall follow-up was for 28 days, follow-up for gametocytaemia was for 14 days.

Findings

The treatment groups were similar in baseline characteristics and there was only one loss to follow-up. Compared to AS-AQ, both MB-containing regimens were associated with significantly reduced gametocyte carrier rates during follow-up days 3, 7, and 14. This effect was seen both in patients with and without P. falciparum gametocytaemia at baseline.

Interpretation

MB reveals pronounced gametocytocidal activity which appears to act against both existing and developing P. falciparum gametocytes. MB-based combination therapy thus has the potential to reduce transmission of P. falciparum malaria in endemic regions, which has important implications for future elimination and eradication strategies.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00354380","term_id":"NCT00354380"}}NCT00354380     

Randomized Trial of Piperaquine with Sulfadoxine-Pyrimethamine or Dihydroartemisinin for Malaria Intermittent Preventive Treatment in Children

Background

The long terminal half life of piperaquine makes it suitable for intermittent preventive treatment for malaria but no studies of its use for prevention have been done in Africa. We did a cluster randomized trial to determine whether piperaquine in combination with either dihydroartemisin (DHA) or sulfadoxine-pyrimethamine (SP) is as effective, and better tolerated, than SP plus amodiaquine (AQ), when used for intermittent preventive treatment in children delivered by community health workers in a rural area of Senegal.

Methods

Treatments were delivered to children 3–59 months of age in their homes once per month during the transmission season by community health workers. 33 health workers, each covering about 60 children, were randomized to deliver either SP+AQ, DHA+PQ or SP+PQ. Primary endpoints were the incidence of attacks of clinical malaria, and the incidence of adverse events.

Results

1893 children were enrolled. Coverage of monthly rounds and compliance with daily doses was similar in all groups; 90% of children received at least 2 monthly doses. Piperaquine combinations were better tolerated than SP+AQ with a significantly lower risk of common, mild adverse events. 103 episodes of clinical malaria were recorded during the course of the trial. 68 children had malaria with parasitaemia >3000/µL, 29/671 (4.3%) in the SP+AQ group, compared with 22/604 (3.6%) in the DHA+PQ group (risk difference 0.47%, 95%CI −2.3%,+3.3%), and 17/618 (2.8%) in the SP+PQ group (risk difference 1.2%, 95%CI −1.3%,+3.6%). Prevalences of parasitaemia and the proportion of children carrying Pfdhfr and Pfdhps mutations associated with resistance to SP were very low in all groups at the end of the transmission season.

Conclusions

Seasonal IPT with SP+PQ in children is highly effective and well tolerated; the combination of two long-acting drugs is likely to impede the emergence of resistant parasites.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00529620","term_id":"NCT00529620"}}NCT00529620     

A Comparative Study of the Spatial Distribution of Schistosomiasis in Mali in 1984–1989 and 2004–2006

Background

We investigated changes in the spatial distribution of schistosomiasis in Mali following a decade of donor-funded control and a further 12 years without control.

Methodology/Principal Findings

National pre-intervention cross-sectional schistosomiasis surveys were conducted in Mali in 1984–1989 (in communities) and again in 2004–2006 (in schools). Bayesian geostatistical models were built separately for each time period and on the datasets combined across time periods. In the former, data from one period were used to predict prevalence of schistosome infections for the other period, and in the latter, the models were used to determine whether spatial autocorrelation and covariate effects were consistent across periods. Schistosoma haematobium prevalence was 25.7% in 1984–1989 and 38.3% in 2004–2006; S. mansoni prevalence was 7.4% in 1984–1989 and 6.7% in 2004–2006 (note the models showed no significant difference in mean prevalence of either infection between time periods). Prevalence of both infections showed a focal spatial pattern and negative associations with distance from perennial waterbodies, which was consistent across time periods. Spatial models developed using 1984–1989 data were able to predict the distributions of both schistosome species in 2004–2006 (area under the receiver operating characteristic curve was typically >0.7) and vice versa.

Conclusions/Significance

A decade after the apparently successful conclusion of a donor-funded schistosomiasis control programme from 1982–1992, national prevalence of schistosomiasis had rebounded to pre-intervention levels. Clusters of schistosome infections occurred in generally the same areas accross time periods, although the precise locations varied. To achieve long-term control, it is essential to plan for sustainability of ongoing interventions, including stengthening endemic country health systems.     

Discrepant Prevalence and Incidence of Leishmania Infection between Two Neighboring Villages in Central Mali Based on Leishmanin Skin Test Surveys

Apart from a single report, the last publication of cutaneous leishmaniasis (CL) in Mali dates back more than 20 years. The absence of information on the current status of CL in Mali led us to conduct a cohort study in Kemena and Sougoula, two villages in Central Mali from which cases of CL have been recently diagnosed by Mali''s reference dermatology center in Bamako. In May 2006, we determined the baseline prevalence of Leishmania infection in the two villages using the leishmanin skin test (LST). LST-negative individuals were then re-tested over two consecutive years to estimate the annual incidence of Leishmania infection. The prevalence of Leishmania infection was significantly higher in Kemena than in Sougoula (45.4% vs. 19.9%; OR: 3.36, CI: 2.66–4.18). The annual incidence of Leishmania infection was also significantly higher in Kemena (18.5% and 17% for 2007 and 2008, respectively) than in Sougoula (5.7% for both years). These data demonstrate that the risk of Leishmania infection was stable in both villages and confirm the initial observation of a significantly higher risk of infection in Kemena (OR: 3.78; CI: 2.45–6.18 in 2007; and OR: 3.36; CI: 1.95–5.8 in 2008; P<0.005). The absence of spatial clustering of LST-positive individuals in both villages indicated that transmission may be occurring anywhere within the villages. Although Kemena and Sougoula are only 5 km apart and share epidemiologic characteristics such as stable transmission and random distribution of LST-positive individuals, they differ markedly in the prevalence and annual incidence of Leishmania infection. Here we establish ongoing transmission of Leishmania in Kemena and Sougoula, Central Mali, and are currently investigating the underlying factors that may be responsible for the discrepant infection rates we observed between them.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00344084","term_id":"NCT00344084"}}NCT00344084     

Identification and characterization of microsatellites for striped bass from repeat-enriched libraries

Striped bass (Morone saxatilis) is economically important in the US due to its value as an aquaculture species and in supporting commercial and recreational fisheries, especially those off the Atlantic coast and in the Gulf of Mexico. Modern strategies for managing fishery populations and aquaculture broodstocks employ the use of molecular genetic markers to identify individuals, assign parentage, and characterize population genetic structure and levels of inbreeding and migration. As part of a collaborative effort to utilize molecular genetic technologies in striped bass breeding programs we generated microsatellite markers for use in population genetic studies, broodstock selection and management strategies, and the construction of a genetic map. We developed 345 new microsatellite markers for striped bass, a subset (n=71) of which was characterized by genotyping samples from two striped bass broodstock populations to evaluate marker polymorphism, percent heterozygosity, Hardy–Weinberg equilibrium (HWE), linkage disequilibrium (LD) and utility for population genetic studies.