Distribution of ace-1R and resistance to carbamates and organophosphates in Anopheles gambiae s.s. populations from Côte d'Ivoire

<p>Abstract</p> <p>Background</p> <p>The spread of pyrethroid resistance in <it>Anopheles gambiae s.s. </it>is a critical issue for malaria vector control based on the use of insecticide-treated nets. Carbamates and organophosphates insecticides are regarded as alternatives or supplements to pyrethroids used in nets treatment. It is, therefore, essential to investigate on the susceptibility of pyrethroid resistant populations of <it>An. gambiae s.s. </it>to these alternative products.</p> <p>Methods</p> <p>In September 2004, a cross sectional survey was conducted in six localities in Côte d'Ivoire: Toumbokro, Yamoussoukro, Toumodi in the Southern Guinea savannah, Tiassalé in semi-deciduous forest, then Nieky and Abidjan in evergreen forest area. <it>An. gambiae </it>populations from these localities were previously reported to be highly resistant to pyrethroids insecticides. Anopheline larvae were collected from the field and reared to adults. Resistance/susceptibility to carbamates (0.4% carbosulfan, 0.1% propoxur) and organophosphates (0.4% chlorpyrifos-methyl, 1% fenitrothion) was assessed using WHO bioassay test kits for adult mosquitoes. Then, PCR assays were run to determine the molecular forms (M) and (S), as well as phenotypes for insensitive acetylcholinesterase (AChE1) due to G119S mutation.</p> <p>Results</p> <p>Bioassays showed carbamates (carbosulfan and propoxur) resistance in all tested populations of <it>An. gambiae s.s. </it>In addition, two out of the six tested populations (Toumodi and Tiassalé) were also resistant to organophosphates (mortality rates ranged from 29.5% to 93.3%). The M-form was predominant in tested samples (91.8%). M and S molecular forms were sympatric at two localities but no M/S hybrids were detected. The highest proportion of S-form (7.9% of <it>An. gambiae </it>identified) was in sample from Toumbokro, in the southern Guinea savannah. The G119S mutation was found in both M and S molecular forms with frequency from 30.9 to 35.2%.</p> <p>Conclusion</p> <p>This study revealed a wide distribution of insensitive acetylcholinesterase due to the G119S mutation in both M and S molecular forms of the populations of <it>An. gambiae s.s. </it>tested. The low cross-resistance between carbamates and organophosphates highly suggests involvement of other resistance mechanisms such as metabolic detoxification or F290V mutation.</p

Financial Bubbles : New Evidence from South Africa’s Stock Market

We provide new empirical evidence of bubbles timing in the stock market of South Africa. We apply the generalized sup ADF (GSADF) unit root test of Phillips et al. (2015) to monthly share prices from January 1960 to July 2019, to detect explosive behaviors. Results indicate that, overall, South Africa’s stock market has been exuberant during the period 1960-2019. We find strong evidence of three bubble episodes during the periods of April 1968 to July 1969, December 1979 to November 1980 and April 2006 to May 2008 in the stock market of South Africa. The last two bubbles correspond to the 1979 international oil crisis and the 2008 financial crisis suggesting that the south african stock market is still vulnerable to exogenous shocks

Caractérisation De L’aquifère Superficiel Du Bassin Sédimentaire De Kandi (Nord-Est Bénin, Afrique Ouest): Nature Et Structure Du Reservoir, Hydrodynamique

Cet article aborde la caractérisation du bassin sédimentaire de Kandi, notamment sa structure hydrogéologique et son fonctionnement hydrodynamique qui sont encore mal connus, précisément dans sa portion superficielle captée par des forages d’exploitation et directement concernée par l’impact de la variabilité et des changements climatiques. L’analyse de la structure du système aquifère du bassin a été menée par corrélation géologique et hydrogéologique de logs de forages existants. L’étude hydrodynamique a été conduite en considérant les données de pompage d’essai existantes et deux&nbsp; campagnes de mesures piézométriques (août 2016 pour les hautes eaux, puis avril 2017 pour les basses eaux). Les résultats confirment la nature essentiellement gréseuse et conglomératique de la lithologie des deux couches captées par les forages hydrauliques, à savoir, selon les secteurs, la formation continentale de Wèrè (Cambro-Ordovicien) et la formation marine de Kandi (Ordovicien supérieur à Silurien inférieur). Les nappes phréatiques de ces deux formations plus ou moins perméables et directement superposées l’une sur l’autre, sont en interconnexion hydraulique pour former une seule et même nappe d’eau souterraine. Les valeurs des paramètres hydrodynamiques calculées montrent que la transmissivité du sytsème aquifère est de l’ordre de 3,08E-02 à 2,99E-05 m²/s, et la perméabilité de l’ordre de 1,30E-03 et 3,37E-06 m/s. L’écoulement de l’eau souterraine s’effectue globalement du Sud vers le Nord, conformément au pendage régional des couches et à la tectonique. This article deals with the characterization of sedimentary Kandi basin, in particular its hydrogeological structure and hydrodynamic functioning, which are still poorly known, precisely in its superficial part captured by exploitation boreholes and directly concerned by the impact of climate variability and change.&nbsp; The analysis of the structure of the basin's aquifer system was carried out by geological and hydrogeological correlation of existing borehole logs. The hydrodynamic study was carried out by considering existing test pumping data and two piezometric measurement campaigns (August 2016 for high waters, then April 2017 for low waters). The results confirm the essentially sandstone and conglomeratic&nbsp; nature of the lithology of the two layers captured by the hydraulic boreholes, namely, depending on the sector, the continental Wèrè formation (Cambro-Ordovician) and the marine Kandi formation (Upper Ordovician to Lower Silurian). The water tables of these two more or less permeable formations, which are directly superimposed on each other, are hydraulically interconnected to form a single groundwater table. The values of hydrodynamic parameters calculated show that transmissivity of the aquifer system ranges from 3.08E-02 to 2.99E-05 m²/s, and permeability ranges from 1.30E-03 to 3.37E-06 m/s. Groundwater flow is generally from South to North, in accordance with the regional dip of the layers and tectonic

Monitoring of human rights relating to the management of faecal sludge in the district of Bamako

This record includes an extended abstract and MP4 presentation. Presented at the 42nd WEDC International Conference

Update on resistance status of Anopheles gambiae s.s. to conventional insecticides at a previous WHOPES field site, "Yaokoffikro", 6 years after the political crisis in Côte d'Ivoire.

BACKGROUND: At Yaokoffikro field site near Bouaké, in central Côte d'Ivoire, a group of experimental huts built in 1996 served over many years for the evaluation of insecticides against highly resistant mosquitoes. Breeding sites of mosquitoes and selection pressure in the area were maintained by local farming practices until a war broke out in September 2002. Six years after the crisis, we conducted bioassays and biochemical analysis to update the resistance status of Anopheles gambiae s.s. populations and detect other potential mechanisms of resistance that might have evolved. METHODS: An. gambiae s.s. larvae from Yaokoffikro were collected in breeding sites and reared to adults. Resistance status of this population to insecticides was assessed using WHO bioassay test kits for adult mosquitoes with seven insecticides: two pyrethroids, a pseudo-pyrethroid, an organochloride, two carbamates and an organophosphate.Molecular and biochemical assays were carried out to identify the L1014F kdr and ace-1R alleles in individual mosquitoes and to detect potential increase in mixed function oxidases (MFO), non-specific esterases (NSE) and glutathione S-transferases (GST) activity. RESULTS: High pyrethroids, DDT and carbamate resistance was confirmed in An. gambiae s.s. populations from Yaokoffikro. Mortality rates were less than 70% with pyrethroids and etofenprox, 12% with DDT, and less than 22% with the carbamates. Tolerance to fenitrothion was observed, with 95% mortality after 24 h.PCR analysis of samples from the site showed high allelic frequency of the L1014F kdr (0.94) and the ace-1R (0.50) as before the crisis. In addition, increased activity of NSE, GST and to a lesser extent MFO was found relative to the reference strain Kisumu. This was the first report detecting enhanced activity of these enzymes in An. gambiae s.s from Yaokoffikro, which could have serious implications in detoxification of insecticides. Their specific roles in resistance should be investigated using additional tools. CONCLUSION: The insecticide resistance profile at Yaokoffikro appears multifactorial. The site presents a unique opportunity to evaluate its impact on the protective efficacy of insecticidal products as well as new tools to manage these complex mechanisms. It calls for innovative research on the behaviour of the local vector, its biology and genetics that drive resistance

Identification and characterization of Anopheles spp. breeding habitats in the Korhogo area in northern Côte d’Ivoire: a study prior to a Bti-based larviciding intervention

Abstract Background Although larviciding may be a valuable tool to supplement long-lasting insecticide nets (LLINs) in West Africa in different ecological settings, its actual impact on malaria burden and transmission has yet to be demonstrated. A randomized controlled trial was therefore undertaken to assess the effectiveness of larviciding using Bacillus thuringiensis israeliensis (Bti) in addition to the use of LLINs. In order to optimally implement such a larviciding intervention, we first aimed to identify and to characterize the breeding habitats of Anopheles spp. in the entire study area located in the vicinity of Korhogo in northern Côte d’Ivoire. Methods We conducted two surveys during the rainy and the dry season, respectively, in the thirty villages around Korhogo involved in the study. In each survey, water bodies located within a 2 km radius around each village were identified and assessed for the presence of mosquito larvae. We morphologically identified the larvae to the genus level and we characterized all of the habitats positive for Anopheles spp. larvae based on a predefined set of criteria. Results Overall, 620 and 188 water bodies positive for Anopheles spp. larvae were sampled in the rainy and the dry season, respectively. A broad range of habitat types were identified. Rice paddies accounted for 61% and 57% of the habitats encountered in the rainy and the dry season, respectively. In the rainy season, edges of rivers and streams (12%) were the second most abundant habitats for Anopheles spp. larvae. More than 90% of the Anopheles spp. breeding habitats were surrounded by green areas. Dams, ponds and drains produced higher numbers of Anopheles spp. larvae per square meter than rice paddies (RR = 1.51; 95% CI: 1.18–1.94; P = 0.0010). The density of Anopheles spp. larvae was significantly higher in habitats surrounded by low-density housing (RR = 4.81; 95% CI: 1.84–12.60; P = 0.0014) and green areas (RR = 3.96; 95% CI: 1.92–8.16; P = 0.0002] than habitats surrounded by high-density housing. Turbid water [RR = 1.42 (95% CI: 1.15–1.76; P = 0.0012) was associated with higher densities of Anopheles spp. larvae. The likelihood of finding mosquito pupae in Anopheles spp. breeding habitats was higher in the dry season (OR = 5.92; 95% CI: 2.11–16.63; P = 0.0007) than in the rainy season. Conclusions Rice paddies represented the most frequent habitat type for Anopheles spp. larvae in the Korhogo area during both the rainy and the dry seasons. Anopheles spp. breeding habitats covered a very large and dynamic area in the rainy season whereas they were fewer in number in the dry season. In this context, implementing a larviciding strategy from the end of the rainy season to the dry season is presumably the most cost-effective strategy

Impact of sunlight exposure on the residual efficacy of biolarvicides Bacillus thuringiensis israelensis and Bacillus sphaericus against the main malaria vector, Anopheles gambiae

Abstract Background Biotic and abiotic factors have been reported to affect the larvicidal efficacy of Bacillus thuringiensis israelensis (Bti) and Bacillus sphaericus (Bs), although the extent to which they are affected has been poorly documented. This paper studies the effect of sunlight exposure on the efficacy of a new larvicide formulation based on both Bti and Bs, herein after referred to as BTBSWAX, applied against two different larval stages. Methods The emergence of inhibition exhibited by BTBSWAX at three different dosages (1 g/m2, 1.5 g/m2, and 2 g/m2) was monitored under semi-field conditions using a total of 32 containers comprising 16 that were covered and 16 that were uncovered. Two experiments were conducted using first- and second-instar larvae of Anopheles gambiae, respectively. Results BTBSWAX at 2 g/m2 in covered containers exhibited high emergence inhibition (> 80%) when larvae were exposed from 1st instar on day-6 post-treatment, whereas the emergence inhibition was only 28% in uncovered containers. For larvae exposed from 1st instar on day-12 post-treatment, the emergence inhibition was moderate (70%) in covered containers but was low (< 20%) in uncovered containers. For larvae exposed from 2nd instar on day-10 post-treatment, the emergence inhibition was moderate (31%) in covered containers but was very low (< 10%) in uncovered containers. Moreover, the residual efficacy of BTBSWAX was markedly affected by environmental stresses, including sunlight exposure (Hazard ratio (HR) = 0.12, p < 0.001 and HR = 0.63, p = 0.033 for BTBSWAX at 2 g/m2 against 1st and 2nd instar larvae, respectively). Conclusion These findings emphasize the impact of environmental variables (e.g., sunlight exposure) on the residual efficacy of Bti and Bs biolarvicides in the field. They hence highlight the need to take these factors into account for larvicide formulation development processes. Moreover, studies of the ecology of Anopheles larvae in targeted areas are also crucial for the integration of larval control strategies into malaria transmission plans devised by national malaria control programmes of endemic countries

The Management of Protected Areas in Seven Countries of West and Central Africa

Note portant sur l’auteur Introduction Africa harbours a great variety of ecosystems and almost one-third of the biological diversity of the world (IUCN, 2005) but it is also the continent that suffers from the highest rates of poverty on the planet. In order to try to protect natural resources while ensuring the development of its people, the creation and management of protected areas is widely practised and recognized at the international level. It could even be said that the conservation o..

Facteurs de risques de l’hemorragie du post partum au CSREF de Niono: Postpartum hemorrhage risk factors in Niono

Dans le district sanitaire de Niono l’hémorragie du post-partum (HPP) était définie comme toutes les hémorragies qui surviennent immédiatement après l’accouchement et dans les 42 jours du post-partum. En 2015, la fréquence de l’HPP s’y élevait à 1,34% avec un taux de décès de 8,5% contre 1,42% avec un de décès de 5,5% en 2016. L’objectif principal de ce thème était d’étudier les facteurs de risque de survenue des HPP. Méthode : il s’agissait d’une étude transversale réalisée à la maternité du Csréf de Niono du 1er janvier au 31 décembre 2018. Les données recueillies à travers l’exploitation des dossiers médicaux et transcrites sur un questionnaire ont été analysées sur SPSS version 20 pour déterminer les facteurs de risque d’HPP. La confidentialité et l’éthique ont été respectées. Résultats : Sur 1894 admissions, l’hémorragie du postpartum&nbsp;avait une fréquence de 2,16%. Les parturientes résidant hors de Niono représentaient 82,9%, non scolarisées à 82,9%, référées par Cscom à 46,3%. Chez nos patientes 78,1% avaient bénéficié d’une délivrance active. Au total 68,3% avait une rétention placentaire, 75,6% une inertie utérine, prises en charge par la Gestion Active de la Troisième Phase de l’Accouchement (GATPA). Le pronostic maternel était bon dans 97,6% des cas. Il s’agissait d’une hémorragie immédiate pour 92,7%. Conclusion : L’HPP est une urgence obstétricale fréquente et un accent particulier doit être mis sur la prévention en maîtrisant les facteurs de risques obstétricaux et en appliquant la GATPA. ABSTRACT: Introduction: In the Niono Health District, postpartum hemorrhage was defined as all hemorrhages that occur immediately after delivery and within 42 days postpartum. In 2015, the frequency of postpartum hemorrhage was 1.34% with a death rate of 8.5%, compared to 1.42% with a death rate of 5.5% in 2016. The main objective of this theme was to study the risk factors for the occurrence of postpartum hemorrhage. Method: This was a cross-sectional study carried out at the maternity ward of the Csréf de Niono from 1 January to 31 December 2018. Data collected through the use of medical records and transcribed to a questionnaire were analyzed on SPSS version 20 to determine risk factors for PPH. Results: Out of 1894 admissions, postpartum hemorrhage had a frequency of 2.16%. Patients residing outside Niono accounted for 82.9%, 82.9% were out of school and 46.3% were referred by Cscom. In our patients 78.1% had been actively delivered. A total of 68.3% had placental retention, 75.6% had uterine inertia, which was managed by Active Management of the Third Stage of Labor. The maternal prognosis was good in 97.6% of cases. It was an immediate hemorrhage for 92.7%. Conclusion: PPH is a frequent obstetric emergency and special emphasis must be placed on prevention by controlling obstetric risk factors and applying AMTSL

CHANGEMENT CLIMATIQUE, GEOMORPHOLOGIE ET INONDABILITE DE LA PLAINE ALLUVIALE DU FLEUVE NIGER A NIAMEY (NIGER)

International audienc