scholarly journals 20-Hydroxyecdysone (20E) signaling as a promising target for the chemical control of malaria vectors

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Elodie Ekoka ◽  
Surina Maharaj ◽  
Luisa Nardini ◽  
Yael Dahan-Moss ◽  
Lizette L. Koekemoer
Keyword(s):  
Vector Control ◽  
Signaling Pathway ◽  
Malaria Vector ◽  
Vector Competence ◽  
Rapid Development ◽  
World Health ◽  
Malaria Vectors ◽  
Malaria Vector Control ◽  
Insect Growth Regulators ◽  
Vector Abundance

AbstractWith the rapid development and spread of resistance to insecticides among anopheline malaria vectors, the efficacy of current World Health Organization (WHO)-approved insecticides targeting these vectors is under threat. This has led to the development of novel interventions, including improved and enhanced insecticide formulations with new targets or synergists or with added sterilants and/or antimalarials, among others. To date, several studies in mosquitoes have revealed that the 20-hydroxyecdysone (20E) signaling pathway regulates both vector abundance and competence, two parameters that influence malaria transmission. Therefore, insecticides which target 20E signaling (e.g. methoxyfenozide and halofenozide) may be an asset for malaria vector control. While such insecticides are already commercially available for lepidopteran and coleopteran pests, they still need to be approved by the WHO for malaria vector control programs. Until recently, chemicals targeting 20E signaling were considered to be insect growth regulators, and their effect was mostly studied against immature mosquito stages. However, in the last few years, promising results have been obtained by applying methoxyfenozide or halofenozide (two compounds that boost 20E signaling) to Anopheles populations at different phases of their life-cycle. In addition, preliminary studies suggest that methoxyfenozide resistance is unstable, causing the insects substantial fitness costs, thereby potentially circumventing one of the biggest challenges faced by current vector control efforts. In this review, we first describe the 20E signaling pathway in mosquitoes and then summarize the mechanisms whereby 20E signaling regulates the physiological processes associated with vector competence and vector abundance. Finally, we discuss the potential of using chemicals targeting 20E signaling to control malaria vectors.

scholarly journals Quantifying and characterizing hourly human exposure to malaria vectors bites in rural southwest Burkina Faso

2019 ◽  
Author(s):  
D.D Soma ◽  
B Zogo ◽  
P Taconet ◽  
A Somé ◽  
S Coulibaly ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Vector Control ◽  
Rural Area ◽  
Malaria Vector ◽  
Human Exposure ◽  
Protective Efficacy ◽  
Indoor Residual Spraying ◽  
World Health ◽  
Malaria Vectors ◽  
Malaria Vector Control

AbstractBackgroundTo sustain the efficacy of malaria vector control, the World Health Organization (WHO) recommends the combination of effective tools. Before designing and implementing additional strategies in any setting, it is critical to monitor or predict when and where transmission occurs. However, to date, very few studies have quantified the behavioural interactions between humans and Anopheles vectors. Here, we characterized residual transmission in a rural area of Burkina Faso where long lasting insecticidal nets (LLIN) are widely used.MethodsWe analysed data on both human and malaria vectors behaviours from 27 villages to measure hourly human exposure to vector bites in dry and rainy seasons using mathematical models. We estimated the protective efficacy of LLINs and characterised where (indoors vs. outdoors) and when both LLIN users and non-users were exposed to vector bites.ResultsThe percentage of the population who declared sleeping under a LLIN the previous night was very high regardless of the season, with an average LLIN use ranging from 92.43% to 99.89%. The use of LLIN provided > 80% protection against exposure to vector bites. The proportion of exposure for LLIN users was 29-57% after 05:00 and 0.05-12 % before 20:00. More than 80% of exposure occurred indoors for LLIN users and the estimate reached 90% for children under five years old in the dry cold season.ConclusionsThis study supports the current use of LLIN as a primary malaria vector control tool. It also emphasises the need to complement LLIN with indoor-implemented measures such as indoor residual spraying (IRS) and/or house improvement to effectively combat malaria in the rural area of Diébougou. Furthermore, malaria elimination programmes would also require strategies that target outdoor biting vectors to be successful in the area.

scholarly journals Resting behaviour of malaria vectors in highland and lowland sites of western Kenya: Implication on malaria vector control measures

PLoS ONE ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. e0224718 ◽  
Author(s):  
Maxwell G. Machani ◽  
Eric Ochomo ◽  
Fred Amimo ◽  
Jackline Kosgei ◽  
Stephen Munga ◽  
...  
Keyword(s):  
Vector Control ◽  
Malaria Vector ◽  
Control Measures ◽  
Malaria Vectors ◽  
Malaria Vector Control ◽  
Western Kenya ◽  
Resting Behaviour

scholarly journals Efficacy of broflanilide (VECTRON™ T500), a new meta-diamide insecticide, for indoor residual spraying against pyrethroid-resistant malaria vectors

2020 ◽  
Author(s):  
Corine Ngufor ◽  
Renaud Govoetchan ◽  
Augustin Fongnikin ◽  
Estelle Vigninou ◽  
Thomas Syme ◽  
...  
Keyword(s):  
Vector Control ◽  
Malaria Vector ◽  
Indoor Residual Spraying ◽  
Malaria Vectors ◽  
Cross Resistance ◽  
Malaria Vector Control ◽  
Application Rates ◽  
Wettable Powder ◽  
Cone Bioassay ◽  
Pirimiphos Methyl

AbstractThe rotational use of insecticides with different modes of action for indoor residual spraying (IRS) is recommended for improving malaria vector control and managing insecticide resistance. A more diversified portfolio of IRS insecticides is required; insecticides with new chemistries which can provide improved and prolonged control of insecticide-resistant vector populations are urgently needed. Broflanilide is a newly discovered insecticide being considered for malaria vector control. We investigated the efficacy of a wettable powder (WP) formulation of broflanilide (VECTRON™ T500) for IRS on mud and cement wall substrates in WHO laboratory and experimental hut studies against pyrethroid-resistant malaria vectors in Benin, in comparison with pirimiphos-methyl CS (Actellic® 300CS). There was no evidence of cross-resistance to pyrethroids and broflanilide in CDC bottle bioassays. In laboratory cone bioassays, mortality of susceptible and pyrethroid-resistant A. gambiae s.l. with broflanilide WP treated substrates was >80% for 6-14 months. At application rates of 100mg/m2 and 150 mg/m2, mortality of wild pyrethroid-resistant A. gambiae s.l. entering treated experimental huts in Covè, Benin was 57%-66% with broflanilide WP and did not differ significantly from pirimiphos-methyl CS (57-66% vs. 56%, P>0.05). Mosquito mortality did not differ between the two application rates and local wall substrate-types tested (P>0.05). Throughout the 6-month hut trial, monthly wall cone bioassay mortality on broflanilide WP treated hut walls remained >80% for both susceptible and resistant strains of A. gambiae s.l.. Broflanilide shows potential to significantly improve the control of malaria transmitted by pyrethroid-resistant mosquito vectors and would thus be a crucial addition to the current portfolio of IRS insecticides.One Sentence SummaryVECTRON™ T500, a new wettable powder formulation of broflanilide developed for indoor residual spraying, showed high and prolonged activity against wild pyrethroid-resistant malaria vectors, on local wall substrates, in laboratory bioassays and experimental household settings in Benin.

scholarly journals Quantifying and characterizing hourly human exposure to malaria vectors bites to address residual malaria transmission during dry and rainy seasons in rural Southwest Burkina Faso

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
D. D. Soma ◽  
B. Zogo ◽  
P. Taconet ◽  
A. Somé ◽  
S. Coulibaly ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Malaria Transmission ◽  
Rural Area ◽  
Malaria Vector ◽  
Human Exposure ◽  
World Health ◽  
Malaria Vectors ◽  
Malaria Vector Control ◽  
Residual Malaria Transmission ◽  
Dry And Rainy Seasons

Abstract Background To sustain the efficacy of malaria vector control, the World Health Organization (WHO) recommends the combination of effective tools. Before designing and implementing additional strategies in any setting, it is critical to monitor or predict when and where transmission occurs. However, to date, very few studies have quantified the behavioural interactions between humans and Anopheles vectors in Africa. Here, we characterized residual transmission in a rural area of Burkina Faso where long lasting insecticidal nets (LLIN) are widely used. Methods We analysed data on both human and malaria vectors behaviours from 27 villages to measure hourly human exposure to vector bites in dry and rainy seasons using a mathematical model. We estimated the protective efficacy of LLINs and characterised where (indoors vs. outdoors) and when both LLIN users and non-users were exposed to vector bites. Results The percentage of the population who declared sleeping under a LLIN the previous night was very high regardless of the season, with an average LLIN use ranging from 92.43 to 99.89%. The use of LLIN provided > 80% protection against exposure to vector bites. The proportion of exposure for LLIN users was 29–57% after 05:00 and 0.05–12% before 20:00. More than 80% of exposure occurred indoors for LLIN users and the estimate reached 90% for children under 5 years old in the dry cold season. Conclusions LLINs are predicted to provide considerable protection against exposure to malaria vector bites in the rural area of Diébougou. Nevertheless, LLIN users are still exposed to vector bites which occurred mostly indoors in late morning. Therefore, complementary strategies targeting indoor biting vectors in combination with LLIN are expected to be the most efficient to control residual malaria transmission in this area.

scholarly journals Current status of insecticide resistance in malaria vectors in the Asian countries: a systematic review

F1000Research ◽  
2022 ◽  
Vol 10 ◽  
pp. 200
Author(s):  
Dewi Susanna ◽  
Dian Pratiwi
Keyword(s):  
Systematic Review ◽  
Insecticide Resistance ◽  
Vector Control ◽  
Malaria Vector ◽  
Pyrethroid Resistance ◽  
Current Trend ◽  
Current Status ◽  
Malaria Vectors ◽  
Malaria Vector Control ◽  
Publication Date

Background: The application of insecticides for malaria vector control has led to a global problem, which is the current trend of increased resistance against these chemicals. This study aimed to review the insecticide resistance status was previously determined in Asia and how to implement the necessary interventions. Moreover, the implications of resistance in malaria vector control in this region were studied. Methods: This systematic review was conducted using a predefined protocol based on PRISMA-retrieved articles from four science databases, namely ProQuest, Science Direct, EBSCO, and PubMed in the last ten years (2009 to 2019). The searching process utilized four main combinations of the following keywords: malaria, vector control, insecticide, and Asia. In ProQuest, malaria control, as well as an insecticide, were used as keywords. The following criteria were included in the filter, namely full text, the source of each article, scholarly journal, Asia, and publication date as in the last ten years. Results: There were 1408 articles retrieved during the initial search (ProQuest=722, Science Direct=267, EBSCO=50, PubMed=285, and Scopus=84). During the screening, 27 articles were excluded because of duplication, 1361 based on title and abstract incompatibility with the inclusion criteria, and 20 due to content differences. In the final screening process, 15 articles were chosen to be analyzed. From the 15 articles, it is known that there was organochlorine (DDT), organophosphate (malathion), and pyrethroids resistance in several Anopheles species with a less than 80% mortality rate. Conclusion: This review found multiple resistance in several Anopheles includes resistance to pyrethroid. The reports of pyrethroid resistance were quite challenging because it is considered effective in the malaria vector control. Several countries in Asia are implementing an insecticide resistance management (IRM) strategy against malaria vectors following the Global Plan for IRM.

scholarly journals EFEKTIFITAS PENGGUNAAN KELAMBU BERINSEKTISIDA (LLINs) TERHADAP KASUS MALARIA (Studi Di Desa Ngreco Kecamatan Tegalombo Kabupaten Pacitan Tahun 2016)

2017 ◽  
Vol 15 (1) ◽  
Author(s):  
Rizka Ilmawati ◽  
Sri Mardoyo ◽  
Suroso Bambang Eko Warno
Keyword(s):  
Vector Control ◽  
Malaria Vector ◽  
World Health ◽  
Malaria Vector Control ◽  
Insecticide Treated Nets ◽  
Mosquito Net ◽  
Control Effort ◽  
The World ◽  
Quasi Experimental ◽  
Health Organization

ABSTRACTMalaria is a contagious disease that still becomes wide health problem in the world, including Indonesia.In 2014, API of Pacitan was the highest in East Java with 75 patients suffered from malaria. One of the endemicvillage in Pacitan is Ngreco village. Malaria vector control effort undertaken in the village is the use of insecticidetreatedbed nets, as recommended by the World Health Organization (WHO). The use of insecticide-treated netseffectively prevent transmission of malaria when supported with good care to insecticide-treated nets.This study aims to determine the effectiveness of insecticide-treated nets used by Ngreco Villagecommunity as malaria vector control to the decline in malaria cases. This is a quasi-experimental research. Thedata were collected through interview and sampling. The research sample was 29 homes for interviews and 4insecticide-treated nets used by the community for Bio-assay Test.The results of this study shows a decrease in new case of malaria in 2007-2010 from 23 new cases into2 new cases in 2011 to 2015. The results of efficacy test conducted on four samples of net used by thecommunity showed that net with 30 months of use (effectiveness <80%) are no longer effective to be used as avector control of malaria, while net with 12 months of use (effectiveness> 80%) is still effective to be used asmalaria vector control.The society should pay more attention on how to laundry the net that it is durable as malaria vectorcontrol. The health center needs to conduct controlling of mosquito nets routinely to find out whether the netsare still effective that replacement or dyeing of the of net can be performed.Keywords: Insecticidal mosquito net, effectiveness, malaria

Susceptibility of Anopheles gambiae complex to carbamates and organophosphate insecticides in Uyo, Akwa Ibom State, Nigeria

2020 ◽  
Vol 41 (1) ◽  
pp. 114-118
Author(s):  
N.I. Udoidung ◽  
K.N. Opara ◽  
P.D. Okodi ◽  
N.D. Ekpo ◽  
I. Atting
Keyword(s):  
Vector Control ◽  
Anopheles Gambiae ◽  
Malaria Vector ◽  
Control Strategies ◽  
Sub Saharan Africa ◽  
World Health ◽  
Malaria Vector Control ◽  
Insecticide Susceptibility ◽  
Post Exposure ◽  
Organophosphate Insecticides

Rapid emergence in insecticide resistance among malaria vector populations to commonly used public health insecticides poses a challenge to current malaria vector control strategies and interventions in sub- Saharan Africa. This study was conducted to determine the susceptibility status of female An.gambiae s.l to Propoxur (0.01%) and bendiocarb (0.1%) (carbamate) and pirimiphosmethyl (0.25%) (organophosphate) insecticides in Uyo Metropolis, Akwa Ibom State, Nigeria. The larvae of An. gambiae s.l were collected from natural water bodies and other potential breeding sites from different sites in Uyo Metropolis. Insecticide susceptibility bioassays were performed according to the World Health Organization standard operating procedures on 2-3 days old, sugar-fed but none blood fed female Anopheles mosquitoes. Post exposure mortality after 24 hours and knockdown values for KDT50 and KDT95 were calculated. Knock-down at 1 hour insecticide exposure ranged from 94 % to 100 %. Mortality after 24 hours post exposure was 100% for all insecticides except Propoxur which was 98 %. There was high variability in KDT50 and KDT95 values (in minutes) with propoxur (4.337 and 15.620), Bendiocarb (9.523 and 20.996) and pirimiphosmethyl (39.908 and 61.722) respectively. Adopting the WHO criteria, the mosquitoes were not resistant to any of the insecticides tested. The results therefore showed that vector control campaigns employing the use of any of these insecticides in the study area would not be compromised. However, there is need for continued monitoring to ensure early detection of resistance. Keywords: Anopheles gambiae; insecticide susceptibility; Uyo; Akwa Ibom State; Nigeria.

scholarly journals INSECTICIDE-TREATED BED NETS IN RONDÔNIA, BRAZIL: EVALUATION OF THEIR IMPACT ON MALARIA CONTROL

2014 ◽  
Vol 56 (6) ◽  
pp. 493-497 ◽  
Author(s):  
Gabriel de Deus Vieira ◽  
Sergio de Almeida Basano ◽  
Tony Hiroshi Katsuragawa ◽  
Luís Marcelo Aranha Camargo
Keyword(s):  
Vector Control ◽  
Malaria Vector ◽  
Malaria Incidence ◽  
Secondary Data ◽  
Epidemiological Studies ◽  
World Health ◽  
Bed Nets ◽  
Malaria Vector Control ◽  
Health Organization ◽  
The Impact

Mosquito nets treated with long-lasting insecticide (LLINs), when used in compliance with guidelines of the World Health Organization, may be effective for malaria vector control. In 2012, approximately 150,000 LLINs were installed in nine municipalities in the state of Rondônia. However, no studies have assessed their impact on the reduction of malaria incidence. This study analyzed secondary data of malaria incidence, in order to assess the impact of LLINs on the annual parasite incidence (API). The results showed no statistically significant differences in API one year after LLIN installation when compared to municipalities without LLINs. The adoption of measures for malaria vector control should be associated with epidemiological studies and evaluations of their use and efficiency, with the aim of offering convincing advantages that justify their implementation and limit malaria infection in the Amazon Region.

scholarly journals Assessment of Novel Lehmann’s Funnel Entry Trap Prototypes Performance to Control Malaria Mosquito Populations

2020 ◽  
Author(s):  
Roger Sanou ◽  
Hamidou Maïga ◽  
Etienne M. Bilgo ◽  
P. Simon Sawadogo ◽  
Bazoumana D. Sow ◽  
...  
Keyword(s):  
Vector Control ◽  
Malaria Vector ◽  
Large Scale ◽  
Malaria Vectors ◽  
Malaria Vector Control ◽  
Malaria Mosquito ◽  
Killing Effect ◽  
Vector Density ◽  
Global Consensus ◽  
Community Acceptance

Abstract BackgroundThere is a global consensus that new intervention tools are needed to cross the last miles in malaria elimination/eradication. In a recent study in Burkina Faso, the Lehmann Funnel Entry Trap (LFET) have shown excellent promise in mosquito densities reducing even in area of high insecticide resistance up to 80%. It requires no chemicals and is self-operated. However, one of the issues of the LFET is the big size of the funnel occupying lot of space inside houses. Here we compared the performance of three new prototypes of LFET with reduced size that combine screening and killing effect on mosquitoes. MethodsThe study was carried out for three months during the rainy season both in low and high malaria vector density sites, Soumousso and Vallée du Kou respectively. The original LFET was modified and 3 new prototypes were produced locally and tested over 3 months (8 days/month) to evaluate their effectiveness in trapping and killing mosquitoes entering houses through the windows. ResultsIn both sites, an overall of 78,435 culicine mosquitoes collected in both traps and houses and most of them were mainly Anopheles gambiae s.l. n= 76,558 (98%) and other species represented n = 1,877 (2%). Of the culicine caught in the trial, n= 55,256 (72%) were collected in traps. The 3 new LFET prototypes reduced the indoor density of mosquitoes collected in the houses by a range of 36 to 73% and 69 to 70% in low vector density setting, Soumousso and high vector density area, Vallée du Kou respectively. The prototype 1 caught a greater number of mosquitoes than the prototype 2 whereas no difference was observed between other prototypes in VK3. In Soumousso, the prototypes 1 and 2 collected significantly higher number of mosquitoes compared to the prototypes 3 and 4. ConclusionThis study has shown that the new LFET prototypes are promising for malaria vector control and could enter in the malaria vector control toolbox in the coming years. Therefore, a large-scale study with one of the prototypes is needed on the practical ability and community acceptance of the LFET to control malaria vectors.

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