scholarly journals Assessment of Level of Susceptibility of Anopheles gambiae S.L to Public Health Insecticides in a Malaria Vector Sentinel Site, Rivers State, Nigeria

2019 ◽  
pp. 1-10
Author(s):  
N. Ebere ◽  
I. Atting ◽  
I. Ekerette ◽  
A. Nioking
Keyword(s):  
Anopheles Gambiae ◽  
Malaria Vector ◽  
Indoor Residual Spraying ◽  
Current Status ◽  
Sentinel Site ◽  
Malaria Surveillance ◽  
Anopheles Mosquitoes ◽  
Surveillance Site ◽  
The Status ◽  
Rivers State

Aims: To investigate the status of susceptibility of Anopheles gambiae sensu lato (Diptera: Culicidae) mosquitoes to the WHO-approved insecticides for indoor residual spraying  in field collected samples in a malaria vector sentinel site in Nigeria and Ts to provide an update on the current status of resistance to the major insecticide classes in wild populations of Anopheles gambiae sensu lato Study Design: Field and laboratory –experimental design was used in this study. Place and Duration of the Study: The study was carried out at a malaria surveillance site, established by the National Malaria Elimination Programme at Oduoha-Emohua in Rivers State, between April to September, 2015.  Methodology: Anopheles larvae were collected from stagnant pools around the malaria surveillance site. The mosquitoes were reared to adulthood in the insectary and identified using morphological keys. Two- to three-day old adult female mosquitoes were exposed to standard diagnostic doses of Deltamethrin, Lambdacyhalothrin, Alphacympermethrin, Permethrin, Bendiocarb, Propoxur, DDT and   Premiphos-Methyl using standard WHO protocols, insecticide susceptibility test kits and treated papers. Knockdown every 10 min and mortality 24 h post exposure was noted. All Anopheles mosquitoes tested belonged to the Anopheles gambiae-complex. Results: Mortality results indicated that the vectors were susceptible to Bendiocarb and Alphacympermethrin with mortality rates of 100% and 98% respectively. There was complete resistance to Deltamethrin, Lambdacyhalothrin, Permethrin, Propoxur, DDT and Premiphos-Methyl with mortality ranges of 25%-65%. Conclusion: The present study shows the effectiveness of Bendiocarb and Alphacympermethrin in malaria control with indoor residual spraying. It also provides baseline information for monitoring the status of insecticide resistance in Rivers State.

scholarly journals Effect of bendiocarb based (Ficam® 80% WP) Indoor Residual Spraying on feeding patterns from malaria vectors in Burkina Faso, West Africa.

2020 ◽  
Author(s):  
Sawdetuo Aristide HIEN ◽  
Dieudonné Diloma Soma ◽  
Simon Pengwende Sawadogo ◽  
Serge Bèwadéyir Poda ◽  
Moussa Namountougou ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Anopheles Gambiae ◽  
Malaria Transmission ◽  
Malaria Vector ◽  
Indoor Residual Spraying ◽  
Transmission Risk ◽  
Malaria Vectors ◽  
Anopheles Coluzzii ◽  
Transmission Season ◽  
Density Methods

Abstract Background The fight against vector is essential in malaria prevention strategies in several endemic countries in Africa. In Burkina Faso, malaria transmission is seasonal in most parts of country, so a single round of spraying should provide effective protection against malaria, provided the insecticide remains effective over the entire malaria transmission season. The outcomes of indoor residual spraying towards curtailing malaria transmission are firstly to decrease the life span of vector mosquitoes and also to reduce the malaria vectors density. Methods CDC light trap and early morning collections by pyrethrum spray catches were performed monthly to determine the change in malaria vector indices in sprayed (Diebougou) and unsprayed sites (Dano). The female’s malaria vectors collected by both methods were used to determine their blood feeding, biting and sporozoites rate and malaria transmission risk estimated by entomological inoculation rate. Results Anopheles gambiae complex composed to Anopheles gambiae, Anopheles coluzzii and Anopheles arabiensis were present throughout the transmission season, but An. gambiae was the predominant species collected (P =0.0005), comprising 88% of the total collected and the most infected species. Malaria vectors densities were significantly lower in sprayed villages (n=4,303) compared with unsprayed villages (n=12,569) during post-spraying period (P = 0.0012). In addition, mean human biting rate of An. gambiae sl and An . funestus ss were significantly lower in sprayed areas compared to unsprayed areas (P<0.05). Overall, malaria vector transmission risk was significant lower in villages which received IRS (P=0.0001) whatever the malaria vectors species ( An. gambiae sl and An. funestus ss). Conclusions The results showed that in the sprayed area (Diebougou), vector densities, human biting rates and malaria transmission risks were very lower than unsprayed areas (Dano). The findings also showed a change in vector behavior especially within An. funestus which became more zoophagic following IRS. The indoor residual spraying could be recommanded as control tool in areas where malaria transmission occured a given period of year.

scholarly journals Plasmodium falciparum Sporozoite Rates in Anopheles gambiae s.l. at a University Teaching Hospital and Contiguous Village, Rivers State, Nigeria

2019 ◽  
pp. 1-7
Author(s):  
M. Aline E. Noutcha ◽  
Melina O. Emumejakpor ◽  
Samuel N. Okiwelu
Keyword(s):  
Anopheles Gambiae ◽  
Teaching Hospital ◽  
Indoor Residual Spraying ◽  
Malaria Prevalence ◽  
Malaria Risk ◽  
University Teaching ◽  
Anopheles Gambiae S.L ◽  
Falciparum Sporozoite ◽  
Rivers State ◽  
Hospital Wards

Malaria is a major burden to human health in tropical and sub-tropical areas. In Nigeria, the entire population is at risk. Over the past decade, there had been persistent reports of mosquito nuisance and an increase in malaria prevalence at the University of Port Harcourt Teaching Hospital in lowland rainforest, Rivers State, Nigeria. It was therefore decided to obtain provisional malaria risk data, by determining the sporozoite rates of anthropophilic, endophlic and endophagic Anopheles gambiae s.l. in the hospital wards and rooms in the contiguous village. Standard keys and guides were used for mosquito identification and dissection to observe sporozoites in their salivary glands. More than half of all female Anopheles gambiae caught at the hospital had fed; similarly, 40.9% of Anopheles gambiae collected from the contiguous village had fed. The sporozoite rates were 75.0% and 73.29% at the hospital and the village respectively. These high sporozoite rates and the preponderance of endophilic, endophagic, anthropophilic An. gambiae s.l. among anophelines indicate high malaria risk at both sites. Since indoor residual spraying is not advisable in hospitals, physical (bed/outlet netting) and chemical (ITNs/LLINs) barriers and larval source management are the recommended alternatives.

scholarly journals Insecticide resistance status of malaria vectors Anopheles gambiae (s.l.) of southwest Burkina Faso and residual efficacy of indoor residual spraying with microencapsulated pirimiphos-methyl insecticide

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Dieudonné Diloma Soma ◽  
Barnabas Zogo ◽  
Domonbabele François de Sales Hien ◽  
Aristide Sawdetuo Hien ◽  
Didier Alexandre Kaboré ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Burkina Faso ◽  
Anopheles Gambiae ◽  
Local Population ◽  
Residual Activity ◽  
Indoor Residual Spraying ◽  
Susceptible Strain ◽  
Malaria Vectors ◽  
Pirimiphos Methyl ◽  
Residual Efficacy

Abstract Background The rapid spread of insecticide resistance in malaria vectors and the rebound in malaria cases observed recently in some endemic areas underscore the urgent need to evaluate and deploy new effective control interventions. A randomized control trial (RCT) was conducted with the aim to investigate the benefit of deploying complementary strategies, including indoor residual spraying (IRS) with pirimiphos-methyl in addition to long-lasting insecticidal nets (LLINs) in Diébougou, southwest Burkina Faso. Methods We measured the susceptibility of the Anopheles gambiae (s.l.) population from Diébougou to conventional insecticides. We further monitored the efficacy and residual activity of pirimiphos-methyl on both cement and mud walls using a laboratory susceptible strain (Kisumu) and the local An. gambiae (s.l.) population. Results An. gambiae (s.l.) from Diébougou was resistant to DDT, pyrethroids (deltamethrin, permethrin and alphacypermethrin) and bendiocarb but showed susceptibility to organophosphates (pirimiphos-methyl and chlorpyrimiphos-methyl). A mixed-effect generalized linear model predicted that pirimiphos-methyl applied on cement or mud walls was effective for 210 days against the laboratory susceptible strain and 247 days against the local population. The residual efficacy of pirimiphos-methyl against the local population on walls made of mud was similar to that of cement (OR = 0.792, [0.55–1.12], Tukey’s test p-value = 0.19). Conclusions If data on malaria transmission and malaria cases (as measured trough the RCT) are consistent with data on residual activity of pirimiphos-methyl regardless of the type of wall, one round of IRS with pirimiphos-methyl would have the potential to control malaria in a context of multi-resistant An. gambiae (s.l.) for at least 7 months.

scholarly journals Dental Applications of Carbon Nanotubes

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4423
Author(s):  
Marco A. Castro-Rojas ◽  
Yadira I. Vega-Cantu ◽  
Geoffrey A. Cordell ◽  
Aida Rodriguez-Garcia
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Oral Cavity ◽  
Current Status ◽  
Glass Ionomer ◽  
Oral Infections ◽  
Functional Behavior ◽  
The Status ◽  
Comprehensive Survey ◽  
Dental Applications

Glass ionomer cements and resin-based composites are promising materials in restorative dentistry. However, their limited mechanical properties and the risk of bulk/marginal fracture compromise their lifespan. Intensive research has been conducted to understand and develop new materials that can mimic the functional behavior of the oral cavity. Nanotechnological approaches have emerged to treat oral infections and become a part of scaffolds for tissue regeneration. Carbon nanotubes are promising materials to create multifunctional platforms for dental applications. This review provides a comprehensive survey of and information on the status of this state-of-the-art technology and describes the development of glass ionomers reinforced with carbon nanotubes possessing improved mechanical properties. The applications of carbon nanotubes in drug delivery and tissue engineering for healing infections and lesions of the oral cavity are also described. The review concludes with a summary of the current status and presents a vision of future applications of carbon nanotubes in the practice of dentistry.

Institutional repositories in Africa: Regaining direction

2021 ◽  
pp. 026666692110154
Author(s):  
Usman Ahmed Adam ◽  
Kiran Kaur
Keyword(s):  
Open Access ◽  
Research Output ◽  
Current Status ◽  
African Countries ◽  
Institutional Repositories ◽  
Widespread Implementation ◽  
Typical Performance ◽  
The Status ◽  
Global Access ◽  
And Cluster Analysis

Institutional repositories are powerful tools to facilitate global access to intellectual output by members of the institution, particularly in assisting them to preserve and maximize access to their research output globally. This exploratory study of the status of institutional repositories implementation in African countries using the global Directory of Open Access Repositories (OpenDOAR) and Transparent Ranking: All Repositories by Google Scholar, reports on the operational status and the performance of repositories. Factor analysis and cluster analysis are used to analyze the operational level of institutional repositories in African countries. The analysis showed that the typical performance of institutional repositories remains below average. The possibility of global open access to research results through institutional repositories in South Africa, Kenya, Nigeria, Algeria, Sudan, and Egypt appeared to be relatively more feasible than other African countries. This study concludes that many organizations, institutions, and societies spend great efforts in support of open access implementation in Africa, however, the widespread implementation of institutional repositories is still very slow paced, and the performance of the implemented repositories was below expectation. Suggestions for regaining the intended direction of African institutional repositories are given based on the current status.

scholarly journals Malaria vector species composition and entomological indices following indoor residual spraying in regions bordering Lake Victoria, Tanzania

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Charles Kakilla ◽  
Alphaxard Manjurano ◽  
Karen Nelwin ◽  
Jackline Martin ◽  
Fabian Mashauri ◽  
...  
Keyword(s):  
Species Composition ◽  
Vector Control ◽  
Malaria Vector ◽  
Lake Victoria ◽  
Indoor Residual Spraying ◽  
Transmission Risk ◽  
Malaria Vectors ◽  
Vector Species ◽  
Sporozoite Rate ◽  
Pirimiphos Methyl

Abstract Background Vector control through long-lasting insecticidal nets (LLINs) and focal indoor residual spraying (IRS) is a major component of the Tanzania national malaria control strategy. In mainland Tanzania, IRS has been conducted annually around Lake Victoria basin since 2007. Due to pyrethroid resistance in malaria vectors, use of pyrethroids for IRS was phased out and from 2014 to 2017 pirimiphos-methyl (Actellic® 300CS) was sprayed in regions of Kagera, Geita, Mwanza, and Mara. Entomological surveillance was conducted in 10 sprayed and 4 unsprayed sites to determine the impact of IRS on entomological indices related to malaria transmission risk. Methods WHO cone bioassays were conducted monthly on interior house walls to determine residual efficacy of pirimiphos-methyl CS. Indoor CDC light traps with or without bottle rotator were hung next to protected sleepers indoors and also set outdoors (unbaited) as a proxy measure for indoor and outdoor biting rate and time of biting. Prokopack aspirators were used indoors to capture resting malaria vectors. A sub-sample of Anopheles was tested by PCR to determine species identity and ELISA for sporozoite rate. Results Annual IRS with Actellic® 300CS from 2015 to 2017 was effective on sprayed walls for a mean of 7 months in cone bioassay. PCR of 2016 and 2017 samples showed vector populations were predominantly Anopheles arabiensis (58.1%, n = 4,403 IRS sites, 58%, n = 2,441 unsprayed sites). There was a greater proportion of Anopheles funestus sensu stricto in unsprayed sites (20.4%, n = 858) than in sprayed sites (7.9%, n = 595) and fewer Anopheles parensis (2%, n = 85 unsprayed, 7.8%, n = 591 sprayed). Biting peaks of Anopheles gambiae sensu lato (s.l.) followed periods of rainfall occurring between October and April, but were generally lower in sprayed sites than unsprayed. In most sprayed sites, An. gambiae s.l. indoor densities increased between January and February, i.e., 10–12 months after IRS. The predominant species An. arabiensis had a sporozoite rate in 2017 of 2.0% (95% CI 1.4–2.9) in unsprayed sites compared to 0.8% (95% CI 0.5–1.3) in sprayed sites (p = 0.003). Sporozoite rates were also lower for An. funestus collected in sprayed sites. Conclusion This study contributes to the understanding of malaria vector species composition, behaviour and transmission risk following IRS around Lake Victoria and can be used to guide malaria vector control strategies in Tanzania.

scholarly journals Unravelling population structure heterogeneity within the genome of the malaria vector Anopheles gambiae

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Melina Campos ◽  
Luisa D. P. Rona ◽  
Katie Willis ◽  
George K. Christophides ◽  
Robert M. MacCallum
Keyword(s):  
Population Structure ◽  
Anopheles Gambiae ◽  
Malaria Vector ◽  
Mosquito Species ◽  
Gene Clusters ◽  
Selective Sweeps ◽  
Structure Heterogeneity ◽  
Genomic Studies ◽  
Time Required ◽  
Genomic Regions

Abstract Background Whole genome re-sequencing provides powerful data for population genomic studies, allowing robust inferences of population structure, gene flow and evolutionary history. For the major malaria vector in Africa, Anopheles gambiae, other genetic aspects such as selection and adaptation are also important. In the present study, we explore population genetic variation from genome-wide sequencing of 765 An. gambiae and An. coluzzii specimens collected from across Africa. We used t-SNE, a recently popularized dimensionality reduction method, to create a 2D-map of An. gambiae and An. coluzzii genes that reflect their population structure similarities. Results The map allows intuitive navigation among genes distributed throughout the so-called “mainland” and numerous surrounding “island-like” gene clusters. These gene clusters of various sizes correspond predominantly to low recombination genomic regions such as inversions and centromeres, and also to recent selective sweeps. Because this mosquito species complex has been studied extensively, we were able to support our interpretations with previously published findings. Several novel observations and hypotheses are also made, including selective sweeps and a multi-locus selection event in Guinea-Bissau, a known intense hybridization zone between An. gambiae and An. coluzzii. Conclusions Our results present a rich dataset that could be utilized in functional investigations aiming to shed light onto An. gambiae s.l genome evolution and eventual speciation. In addition, the methodology presented here can be used to further characterize other species not so well studied as An. gambiae, shortening the time required to progress from field sampling to the identification of genes and genomic regions under unique evolutionary processes.

Application of lean practices in small and medium-sized food enterprises

2013 ◽  
Vol 116 (1) ◽  
pp. 125-141 ◽  
Author(s):  
Manoj Dora ◽  
Dirk Van Goubergen ◽  
Maneesh Kumar ◽  
Adrienn Molnar ◽  
Xavier Gellynck
Keyword(s):  
Food Processing ◽  
Lean Manufacturing ◽  
Raw Materials ◽  
Current Status ◽  
Food Sector ◽  
Statistical Process ◽  
Content Type ◽  
Lean Practices ◽  
The Status ◽  
Manufacturing Techniques

Purpose – Recent literature emphasizes the application of lean manufacturing practices to food processing industries in order to improve operational efficiency and productivity. Only a very limited number of studies have focused on the implementation of lean manufacturing practices within small and medium-sized enterprises (SMEs) operating in the food sector. The majority of these studies used the case study method and concentrated on individual lean manufacturing techniques geared towards resolving efficiency issues. This paper aims to analyze the status of the lean manufacturing practices and their benefits and barriers among European food processing SMEs. Design/methodology/approach – A structured questionnaire was developed to collect data. A total of 35 SMEs' representatives, mostly CEOs and operations managers, participated in the survey. The study investigated the role of two control variables in lean implementation: size of the company and country of origin. Findings – The findings show that lean manufacturing practice deployment in food processing SMEs is generally low and still evolving. However, some lean manufacturing practices are more prevalent than others; e.g. flow, pull and statistical process control are not widely used by the food processing SMEs, whereas total productive maintenance, employee involvement, and customer association are more widespread. The key barriers encountered by food SMEs in the implementation of lean manufacturing practices result from the special characteristics of the food sector, such as highly perishable products, complicated processing, extremely variable raw materials, recipes and unpredictable demand. In addition, lack of knowledge and resources makes it difficult for food processing SMEs to embark on the lean journey. Originality/value – The gap in the literature regarding the application of lean manufacturing in the food sector is identified and addressed in this study. The originality of this paper lies in analyzing the current status of the use of lean manufacturing practices among food SMEs in Europe and identifying potential barriers.

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