Impact of annual praziquantel treatment on urogenital schistosomiasis in a seasonal transmission focus in central Senegal

In Sub-Saharan Africa, urogenital schistosomiasis remains a significant public health problem, causing 150.000 deaths/year with approximately 112 million cases diagnosed. The Niakhar district is a disease hotspot in central Senegal where transmission occurs seasonally with high prevalences. The aim of this study was to determine the effect of annual treatment over 3 years on the seasonal transmission dynamics of S. haematobium in 9 villages in the Niakhar district. Adults and children aged between 5 and 60 years were surveyed from 2011 to 2014. Urine samples were collected door-to-door and examined for S. haematobium eggs at baseline in June 2011, and all participants were treated in August 2011 with PZQ (40 mg/kg). After this initial examination, evaluations were conducted at 3 successive time points from September 2011 to March 2014, to measure the efficacy of the annual treatments and the rates of reinfection. Each year, during the transmission period, from July to November-December, malacological surveys were also carried out in the fresh water bodies of each village to evaluate the infestation of the snail intermediate hosts. At baseline, the overall prevalence of S. haematobium infection was 57.7%, and the proportion of heavy infection was 45.3%, but one month after the first treatment high cure rates (92.9%) were obtained. The overall infection prevalence and proportion of heavy infection intensities were drastically reduced to 4.2% and 2.3%, respectively. The level of the first reinfection in February-March 2012 was 9.5%. At follow-up time points, prevalence levels varied slightly between reinfection and treatment from 9.5% in June 2012 to 0.3% in March 2013, 11.2 in June 2013, and 10.1% April 2014. At the end of the study, overall prevalence was significantly reduced from 57.7% to 10.1%. The overall rate of infested Bulinid snails was reduced after repeated treatment from 0.8% in 2012 to 0.5% in 2013. Repeated annual treatments are suggested to have a considerable impact on the transmission dynamics of S. haematobium in Niakhar, due to the nature of the epidemiological system with seasonal transmission. Thus, to maintain this benefit and continue to reduce the morbidity of urogenital schistosomiasis, other approaches should be integrated into the strategy plans of the National program to achieve the goal of urogenital schistosomiasis elimination in seasonal foci in Senegal

A comprehensive analysis of drug resistance molecular markers and Plasmodium falciparum genetic diversity in two malaria endemic sites in Mali.

BACKGROUND: Drug resistance is one of the greatest challenges of malaria control programme in Mali. Recent advances in next-generation sequencing (NGS) technologies provide new and effective ways of tracking drug-resistant malaria parasites in Africa. The diversity and the prevalence of Plasmodium falciparum drug-resistance molecular markers were assessed in Dangassa and Nioro-du-Sahel in Mali, two sites with distinct malaria transmission patterns. Dangassa has an intense seasonal malaria transmission, whereas Nioro-du-Sahel has an unstable and short seasonal malaria transmission. METHODS: Up to 270 dried blood spot samples (214 in Dangassa and 56 in Nioro-du-Sahel) were collected from P. falciparum positive patients in 2016. Samples were analysed on the Agena MassARRAY® iPLEX platform. Specific codons were targeted in Pfcrt, Pfmdr1, Pfdhfr, and Pfdhps, Pfarps10, Pfferredoxin, Pfexonuclease and Pfmdr2 genes. The Sanger's 101-SNPs-barcode method was used to assess the genetic diversity of P. falciparum and to determine the parasite species. RESULTS: The Pfcrt_76T chloroquine-resistance genotype was found at a rate of 64.4% in Dangassa and 45.2% in Nioro-du-Sahel (p = 0.025). The Pfdhfr_51I-59R-108N pyrimethamine-resistance genotype was 14.1% and 19.6%, respectively in Dangassa and Nioro-du-Sahel. Mutations in the Pfdhps_S436-A437-K540-A581-613A sulfadoxine-resistance gene was significantly more prevalent in Dangassa as compared to Nioro-du-Sahel (p = 0.035). Up to 17.8% of the isolates from Dangassa vs 7% from Nioro-du-Sahel harboured at least two codon substitutions in this haplotype. The amodiaquine-resistance Pfmdr1_N86Y mutation was identified in only three samples (two in Dangassa and one in Nioro-du-Sahel). The lumefantrine-reduced susceptibility Pfmdr1_Y184F mutation was found in 39.9% and 48.2% of samples in Dangassa and Nioro-du-Sahel, respectively. One piperaquine-resistance Exo_E415G mutation was found in Dangassa, while no artemisinin resistance genetic-background were identified. A high P. falciparum diversity was observed, but no clear genetic aggregation was found at either study sites. Higher multiplicity of infection was observed in Dangassa with both COIL (p = 0.04) and Real McCOIL (p = 0.02) methods relative to Nioro-du-Sahel. CONCLUSIONS: This study reveals high prevalence of chloroquine and pyrimethamine-resistance markers as well as high codon substitution rate in the sulfadoxine-resistance gene. High genetic diversity of P. falciparum was observed. These observations suggest that the use of artemisinins is relevant in both Dangassa and Nioro-du-Sahel

Testing the applicability of morphometric characterisation in discordant catchments to ancient landscapes: A case study from southern Africa

The ancient landscapes south of the Great Escarpment in southern Africa preserve large-scale geomorphological features despite their antiquity. This study applies and evaluates morphometric indices (such as hypsometry, long profile analysis, stream gradient index, and linear/areal catchment characteristics) to the Gouritz catchment, a large discordant catchment in the Western Cape. Spatial variation of morphometric indices were assessed across catchment (trunk rivers) and subcatchment scales. The hypsometric curve of the catchment is sinusoidal, and a range of curve profiles are evident at subcatchment scale. Hypsometric integrals do not correlate to catchment properties such as area, circularity, relief, and dissection; and stream length gradients do not follow expected patterns, with the highest values seen in the mid-catchment areas. Rock type variation is interpreted to be the key control on morphometric indices within the Gouritz catchment, especially hypsometry and stream length gradient. External controls, such as tectonics and climate, were likely diminished because of the long duration of catchment development in this location. While morphometric indices can be a useful procedure in the evaluation of landscape evolution, this study shows that care must be taken in the application of morphometric indices to constrain tectonic or climatic variation in ancient landscapes because of inherited tectonic structures and signal shredding. More widely, we consider that ancient landscapes offer a valuable insight into long-term environmental change, but refinements to geomorphometric approaches are needed

Th1/Th2 Dichotomy in Obese Women with Gestational Diabetes and Their Macrosomic Babies

International audienceThe aim of the study was to assess T cell differentiation and the modulation of inflammatory cytokines in obese and gestational diabetes mellitus (GDM) women and their macrosomic newborns. Hence, immediately after delivery, blood samples were collected through the mother's arm vein and the umbilical cordon vein. Biochemical parameters measured were HbA1C, glucose, insulin, triglyceride (TG), total cholesterol (Tchol), HDL cholesterol (HDLchol), and LDL cholesterol (LDLchol). T lymphocytes were purified from the total blood with Ficoll-Paque. The mRNA expression of inflammatory markers in T cells was determined by RT-qPCR. We observed that diabetic mothers exhibited higher HbA1C, glycemia, insulinemia, TG, Tchol, HDLchol, and LDLchol levels than control mothers. Glycemia was not significantly different between macrosomic and control newborns. However, insulinemia was high in macrosomic babies. TG, Tchol, HDLchol, and LDLchol were not significantly different between macrosomic and control babies. In diabetic mothers, mRNA expression of the Th1 cell subtype was significantly increased. Th1 markers were upregulated in babies born to diabetic women than in control newborns. However, expression of two Th2 markers (GATA3 and IL-4) was not significantly different between control and GDM women and between their respective newborns. Interestingly, IL-10 mRNA expression was decreased in diabetic mothers and their offsprings. The Th1/Th2 cytokine ratio was increased in GDM obese mothers and their macrosomic newborns, suggesting a proinflammatory status in these subjects

Placental malarial infection as a risk factor for hypertensive disorders during pregnancy in Africa : a case-control study in an urban area of Senegal, West Africa

In tropical countries, malaria and hypertension are common diseases of pregnancy. They have physiopathologic similarities such as placental ischemia, endothelial dysfunction, and production of proinflammatory cytokines. Recent findings suggested their possible link. The authors conducted a case-control study to explore the relation between malaria and hypertension at Guediawaye, a hypoendemic malarial setting in Senegal. Cases were pregnant women admitted to the delivery unit for hypertension. Controls were pregnant women admitted for normal delivery, without any history of hypertension or proteinuria during the present pregnancy. Malarial infection was determined by placental tissue examination. From January to December 2002, 77 cases of gestational hypertension, 113 cases of preeclampsia, 59 cases of eclampsia, and 241 controls were enrolled. Placental malarial infection (PMI) was present in 14 cases (6.3%) and in 15 controls (6.2%). The prevalence of PMI was 4.6% for eclampsia, 4.0% for preeclampsia, and 11.6% for gestational hypertension. In multivariate analysis, PMI appeared to be an independent risk factor for gestational hypertension (adjusted odds ratio = 2.7, 95% confidence interval: 1.0, 7.6). The authors found an association between PMI and nonproteinuric hypertension in women living in a malaria-hypoendemic area. The exact significance of such relation should be clarified in further studies in different settings of malarial endemicity

Traitement De La Peripneumonie Contagieuse Bovine Par L’oxyteTracycline Longe Action Et Transmission Experimentale de la Maladie A Partir de Bovins Traites.

La présente étude visait à évaluer l’effet de l’oxytétracycline longue action (oxytétracycline LA) dans le traitement des bovins atteints de péripneumonie contagieuse bovine (PPCB) et de déterminer le risque de transmission de la maladie à partir d’animaux traités. Une transmission expérimentale a été conduite par la mise en contact de 16 bovins cliniquement sains et séronégatifs vis-à-vis des anticorps contre M. mycoides subsp. mycoides Small Colony (MmmSC) avec 14 bovins naturellement infectés de la maladie et traités avec l’oxytétracycline LA. L’expérimentation a duré 10 mois pendant lesquels tous les animaux ont été suivis cliniquement et prélevés à intervalles réguliers pour analyses de laboratoire. Des examens post mortem ont été réalisés sur tous les animaux afin de déceler des lésions caractéristiques de PPCB et aussi de prélever des échantillons pour analyses de laboratoire. Le traitement des animaux infectés par l’oxytétracycline LA a cliniquement guéri la grande majorité d’entre eux (12/14). Tous les 14 animaux ont séroconverti et l’analyse post-mortem a montré la présence des lésions chroniques dont des séquestres pulmonaires chez 4 d’entre eux; MmmSC a été seulement isolé à partir de ces séquestres. Toutefois les 16 animaux sains mis en contact avec ces 14 animaux sont demeurés cliniquement sains durant toute la période d’expérimentation; à l’autopsie aucune lésion caractéristique de la PPCB n’a été notée et les analyses de laboratoire sont restées négatives. Les résultats de la présente étude peuvent avoir des implications importantes dans le contrôle de la PPCB en Afrique.Mots-clés: Péripneumonie contagieuse bovine - Antibiothérapie - Oxytétracycline -Transmission expérimentale - Séquestres pulmonaires - MaliThis study evaluated the effect of long-acting oxytetracycline (Oxytetracycline LA) in the treatment of cattle infested with contagious bovine pleuropneumonia (CBPP) and to determine the risk of disease transmission from animals treated. Experimental transmission was conducted by contacting 16 cattle clinically healthy and seronegative vis-à-vis the antibodies against M. mycoides subsp. mycoides Small Colony (MmmSC) 14 cattle naturally infected with the disease and treated with oxytetracycline LA. The experiment lasted 10 months during which all animals were monitored clinically and sampled at regular intervals for laboratory analysis. Post-mortem examinations were performed on all animals to detect lesions characteristic of CBPP and also take samples for laboratory analysis. The treatment of animals infected with oxytetracycline LA clinically cured a large majority of them (12/14). All 14 animals were seroconverted and post-mortem analysis showed the presence of chronic lesions including pulmonary sequestrations in 4 of them; MmmSC was only isolated from these receivers. However the 16 healthy animals in contact with these 14 animals remained clinically healthy throughout the experimental period, at autopsy no lesions characteristic of CBPP has been noted and laboratory tests were negative. The results of this study may have important implications in the control of CBPP in Africa.Keywords: Contagious bovine pleuropneumonia - Antibiotic - Oxytetracycline-Experimental transmission - Pulmonary lesions -Mal