scholarly journals Mapping insecticide resistance in mosquitoes to aid malaria control

2020 ◽  
Author(s):  
Catherine L. Moyes ◽  
Duncan Kobia Athinya ◽  
Tara Seethaler ◽  
Katherine Battle ◽  
Marianne Sinka ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Malaria Control ◽  
Pyrethroid Resistance ◽  
Resistance Management ◽  
Resistance Mechanisms ◽  
World Health ◽  
Malaria Vector Control ◽  
Metabolic Resistance ◽  
Insecticide Resistance Management ◽  
Health Organization

AbstractMalaria vector control may be compromised by resistance to insecticides in vector populations. Actions to mitigate against resistance rely on surveillance using standard susceptibility tests, but there are large gaps in the monitoring data. Using a published geostatistical ensemble model, we have generated maps that bridge these gaps and consider the likelihood that resistance exceeds recommended thresholds. Our results show that this model provides more accurate next-year predictions than two simpler approaches. We have used the model to generate district-level maps for the probability that pyrethroid resistance in Anopheles gambiae s.l. exceeds the World Health Organization (WHO) thresholds for susceptibility and confirmed resistance. In addition, we have mapped the three criteria for the deployment of piperonyl butoxide-treated nets that mitigate against the effects of metabolic resistance to pyrethroids. This includes a critical review of the evidence for presence of cytochrome P450-mediated metabolic resistance mechanisms across Africa. The maps for pyrethroid resistance are available on the IR Mapper website where they can be viewed alongside the latest survey data.Significance StatementMalaria control in Africa largely relies on the use of insecticides to prevent mosquitoes from transmitting the malaria parasite to humans, however, these mosquitoes have evolved resistance to these insecticides. To manage this threat to malaria control, it is vital that we map locations where the prevalence of resistance exceeds thresholds defined by insecticide resistance management plans. A geospatial model and data from Africa are used to predict locations where thresholds of resistance linked to specific recommended actions are exceeded. This model is shown to provide more accurate next-year predictions than two simpler approaches. The model is used to generate maps that aid insecticide resistance management planning and that allow targeted deployment of interventions that counter specific mechanisms of resistance.

scholarly journals Evaluating insecticide resistance across African districts to aid malaria control decisions

2020 ◽  
Vol 117 (36) ◽  
pp. 22042-22050 ◽  
Author(s):  
Catherine L. Moyes ◽  
Duncan K. Athinya ◽  
Tara Seethaler ◽  
Katherine E. Battle ◽  
Marianne Sinka ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Pyrethroid Resistance ◽  
Resistance Mechanisms ◽  
World Health ◽  
Malaria Vector Control ◽  
Ensemble Model ◽  
Metabolic Resistance ◽  
The World ◽  
Susceptibility Tests ◽  
Health Organization

Malaria vector control may be compromised by resistance to insecticides in vector populations. Actions to mitigate against resistance rely on surveillance using standard susceptibility tests, but there are large gaps in the monitoring data across Africa. Using a published geostatistical ensemble model, we have generated maps that bridge these gaps and consider the likelihood that resistance exceeds recommended thresholds. Our results show that this model provides more accurate next-year predictions than two simpler approaches. We have used the model to generate district-level maps for the probability that pyrethroid resistance inAnopheles gambiaes.l. exceeds the World Health Organization thresholds for susceptibility and confirmed resistance. In addition, we have mapped the three criteria for the deployment of piperonyl butoxide-treated nets that mitigate against the effects of metabolic resistance to pyrethroids. This includes a critical review of the evidence for presence of cytochrome P450-mediated metabolic resistance mechanisms across Africa. The maps for pyrethroid resistance are available on the IR Mapper website, where they can be viewed alongside the latest survey data.

Section 4. Pyrethroid and endosulfan resistance: selection and cross resistance studies

1993 ◽  
Vol 1 ◽  
pp. 28-35 ◽  
Author(s):  
Neil W. Forrester ◽  
Matthew Cahill ◽  
Lisa J. Bird ◽  
Jacquelyn K. Layland
Keyword(s):  
Insecticide Resistance ◽  
Lower Order ◽  
Management Strategy ◽  
Pyrethroid Resistance ◽  
Resistance Management ◽  
Resistance Mechanisms ◽  
Cross Resistance ◽  
Male And Female ◽  
Insecticide Resistance Management ◽  
Resistance Selection

SummaryResistance to endosulfan and pyrethroids in Helicoverpa armigera in Australia was shown to be due to multiple rather than cross resistance. The independence of the endosulfan and pyrethroid resistance mechanisms vindicates the sequential use of these two groups in Stages I and II of the insecticide resistance management strategy, respectively. Within the cyclodienes, greatest resistance occurred to dieldrin with lower order cross resistance to endosulfan and endrin. Male and female moths expressed cyclodiene resistance equally.

scholarly journals A global analysis of National Malaria Control Programme vector surveillance by elimination and control status in 2018

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Thomas R. Burkot ◽  
Robert Farlow ◽  
Myo Min ◽  
Effie Espino ◽  
Abraham Mnzava ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Vector Control ◽  
Malaria Control ◽  
Resistance Management ◽  
World Health ◽  
Vector Data ◽  
Vector Surveillance ◽  
Priority Vector ◽  
Insecticide Resistance Management ◽  
And Control

Abstract Background Maintaining the effectiveness of the currently recommended malaria vector control interventions while integrating new interventions will require monitoring key recommended indicators to identify threats to effectiveness including physiological and behavioural resistance to insecticides. Methods Country metadata on vector surveillance and control activities was collected using an online survey by National Malaria Control Programmes or partner organization officials. Country and regional surveillance activities were analysed for alignment with indicators for priority vector surveillance objectives recommended by the World Health Organization. Surveillance activities were also compared for countries in the E2020 (eliminating countries) and countries with more intense transmission. Results Significant differences in monitoring priority vector indicators between Africa and Asia-Pacific country programmes were found as well as differences between countries approaching elimination and those controlling malaria. Gaps were found between vector data collected and country management strategies (i.e., for insecticide resistance management and integrated vector control strategies) and for making programmatic decisions on surveillance and control using vector surveillance data. Conclusions Significant opportunities exist for increasing vector data collection on priority indicators and using these data for national programmatic decisions for both proactive insecticide resistance management and enhancing vector control.

Insecticide Resistance in Anopheles stephensi in Somali Region, Eastern Ethiopia

2020 ◽  
Author(s):  
Solomon Yared ◽  
Araya Gebressielasie ◽  
Lambodhar Damodaran ◽  
Victoria Bonnell ◽  
Karen Lopez ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Anopheles Stephensi ◽  
Mortality Rates ◽  
Resistance Mechanisms ◽  
World Health ◽  
Malaria Vectors ◽  
Eastern Ethiopia ◽  
Pyrethroid Insecticides ◽  
Pirimiphos Methyl ◽  
Health Organization

Abstract Background: The movement of malaria vectors into new areas is a growing concern in the efforts to control malaria. The recent report of Anopheles stephensi in eastern Ethiopia has raised the necessity to understand the insecticide resistance status of the vector in the region to better inform vector-based interventions. The aim of this study was to evaluate insecticide resistance in An. stephensi in eastern Ethiopia using two approaches: 1) World Health Organization (WHO) bioassay tests in An. stephensi and 2) genetic analysis of insecticide resistance genes in An. stephensi in eastern Ethiopia. Methods: Mosquito larvae and pupae were collected from Kebridehar. Insecticide susceptibility of An. stephensi was tested with malathion 5%, bendiocarb 0.1%, propoxur 0.1%, deltamethrin 0.05%, permethrin 0.75%, Pirimiphos-methyl 0.25% and DDT 4%, according to WHO standard protocols. Results: All An. stephensi samples were resistant to carbamates, with mortality rates 23% and 21% for bendiocarb and propoxur, respectively. Adult An. stephensi was also resistant to pyrethroid insecticides with mortality rates 67% for deltamethrin and 53% for permethrin. Resistance to DDT and malathion was detected in An. stephensi with mortality rates of 32% as well as An. stephensi was resistance to pirimiphos-methyl with mortality rates 14%. Analysis of the voltage gate sodium channel gene (vgsc) revealed the absence of kdr L1014 mutations. Conclusion: Overall, these findings support that An. stephensi is resistant to several classes of insecticides, most notably pyrethroids. However, the absence of the kdr L1014 gene may suggest non-target site resistance mechanisms. Continuous insecticide resistance monitoring should be carried out in the region to confirm the documented resistance and exploring mechanisms conferring resistance in An. stephensi in Ethiopia.

Section 1. The Australian insecticide resistance management strategy

1993 ◽  
Vol 1 ◽  
pp. 1-4 ◽  
Author(s):  
Neil W. Forrester ◽  
Matthew Cahill ◽  
Lisa J. Bird ◽  
Jacquelyn K. Layland
Keyword(s):  
Insecticide Resistance ◽  
Helicoverpa Armigera ◽  
Pyrethroid Resistance ◽  
Resistance Management ◽  
Grain Legumes ◽  
Pest Species ◽  
Insecticide Resistance Management ◽  
Eastern Australia ◽  
Helicoverpa Armígera ◽  
Chemical Groups

SummaryIn response to field pyrethroid failures against Helicoverpa armigera (Hübner) in early 1983, an insecticide resistance management (IRM) strategy was introduced for insect control in summer crops in eastern Australia. The aims of this strategy were to contain the pyrethroid resistance problem, to prevent re-selection of historical endosulfan resistance (both curative IRM) and to avoid any future problems with organophosphate/carbamate resistance (preventative IRM). An alternation strategy was adopted which was based on the rotation of unrelated chemical groups on a per generation basis, along with a strong recommendation for the use of ovicidal mixtures. These chemical countermeasures were then integrated with other non-chemical control methods (biological and cultural) into a workable integrated pest management programme. The restrictions were applied to all Helicoverpa armigera susceptible crops (including cereals, oilseeds, grain legumes, tomatoes, tobacco and cotton) and even to other co-incident pest species. From its inception, compliance with the voluntary strategy has been exceptional.

scholarly journals Pyrethroid Resistance Status of Aedes (Stegomyia) Aegypti (Linneaus) from Dengue Endemic Areas in Peninsular Malaysia

2020 ◽  
Vol 16 (2) ◽  
Author(s):  
Rosilawati R ◽  
Lee HL ◽  
Nazni WA ◽  
Nurulhusna AH ◽  
Roziah A ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Mosquito Control ◽  
Pyrethroid Resistance ◽  
Resistance Management ◽  
Laboratory Strain ◽  
Control Agent ◽  
Peninsular Malaysia ◽  
World Health ◽  
Resistance Level ◽  
Health Organization

Vector control is still the principal method to control dengue and chemical insecticides, especially the pyrethroids such as permethrin are the forerunners of mosquito control agent. Intensive and extensive use of pyrethroids often result in resistance, thereby hampering control efforts. The present study was conducted to evaluate the susceptible status of Aedes aegypti, the primary vector of dengue against permethrin. A nationwide mosquito sampling via ovitrapping was conducted in 12 dengue hotspots across 5 states in Peninsular Malaysia. Field collected Aedes eggs were hatched and reared until L3 larval and further identified it species. Adult F0 Aedes aegypti were reared until F1 progeny and the female were used in adult assay, performed according to World Health Organization (WHO) protocol as to determine the resistance level. The laboratory strain maintained for more than 1000 generations that were susceptible to permethrin served as the control strain. Evaluation of resistance ratio was assessed by comparing the knockdown rate with laboratory susceptible strain. In this present study, 70% ofAe. aegypti population from dengue hotspots was highly resistance to permethrin. The study clearly demonstrated that widespread of permethrin resistant Ae. aegypti in Malaysian mosquito’s population, indicating the need of implementing an efficient pyrethroid resistance management.

scholarly journals Insecticide susceptibility status and knockdown resistance (kdr) mutation in Aedes albopictus in China

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yong Wei ◽  
Xueli Zheng ◽  
Song He ◽  
Xuli Xin ◽  
Jiachun Zhang ◽  
...  
Keyword(s):  
Mortality Rate ◽  
High Resistance ◽  
Pyrethroid Resistance ◽  
Management Strategies ◽  
Resistance Management ◽  
World Health ◽  
Knockdown Resistance ◽  
Phenotypic Resistance ◽  
Pcr Products ◽  
Health Organization

Abstract Background Aedes (Stegomyia) albopictus (Skuse, 1894) is the main vector of dengue virus in China. The resistance to insecticides is a huge obstacle for the control of this species, and determining its resistance status and mechanisms in China is essential for the implementation of vector management strategies. Methods We have investigated the larval and adult resistance status of Ae. albopictus to deltamethrin in eight field populations in China. Mutations at the voltage-gated sodium channel gene, related to the knockdown resistance (kdr) effect, were detected by sequencing of PCR products. The eight field populations were examined for pyrethroid resistance using the World Health Organization standard bioassays, and the association between the mutations and phenotypic resistance was tested. Results The eight field populations of larvae of Ae. albopictus in China exhibited high resistance to deltamethrin; the RR50 values ranged from 12 (ZJ) to 44 (GZ). Adult bioassay revealed that Ae. albopictus populations were resistant to deltamethrin (mortality rate < 90%), except ZJ population (probably resistant, mortality rate = 93.5%). Long knockdown time in the field populations was consistent with low mortality rates in adult bioassay. F1534S mutation showed increased protection against deltamethrin in all populations except BJ and SJZ populations, whereas I1532T mutation showed increased protection against deltamethrin in only BJ population. Conclusion There were different degrees of resistance to deltamethrin in field Ae. albopictus populations in China. The longest knockdown time and lowest mortality rate observed in Ae. albopictus population in Guangzhou indicate the severity of high resistance to deltamethrin. The patchy distribution of deltamethrin resistance and kdr mutations in Ae. albopictus mosquitoes suggests the necessity for resistance management and developing counter measures to mitigate the spread of resistance. Graphical Abstract

scholarly journals Insecticide resistance characteristic of Anopheles vector species successfully controlled by deployment of pyrethroid and PBO long lasting insecticidal treated nets (LLINs) in Tanzania

2021 ◽  
Author(s):  
Johnson Matowo ◽  
David Weetman ◽  
Patricia Pignatell ◽  
Alexandra Wright ◽  
Jacques Charlwood ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Pyrethroid Resistance ◽  
Cluster Randomized Trial ◽  
World Health ◽  
Malaria Vectors ◽  
Metabolizing Enzymes ◽  
Sub Saharan ◽  
Underlying Mechanisms ◽  
Cluster Randomized ◽  
Health Organization

Long lasting insecticidal nets (LLINs) are a proven tool to reduce malaria transmission, but in Africa efficacy is being reduced by pyrethroid resistance in the major vectors. A cluster randomized trial in Muleba district, Tanzania demonstrated that permethrin LLINs co-treated with piperonyl butoxide (PBO), a synergist that can block pyrethroid-metabolizing enzymes in the mosquito, had much greater efficacy than pyrethroid-only nets. Insecticide resistance profiles and underlying mechanisms were investigated in Anopheles gambiae and An. funestus from Muleba during the trial. Diagnostic dose bioassays using permethrin, together with intensity assays, suggest pyrethroid resistance that is both strong and very common, but not extreme. Transcriptomic analysis found multiple P450 genes over expressed including CYP6M2, CYP6Z3, CYP6P3, CYP6P4, CYP6AA1 and CYP9K1 in An. gambiae and CYP6N1, CYP6M7, CYP6M1 and CYP6Z3 in An. funestus. Indeed, very similar suites of P450 enzymes commonly associated with resistant populations elsewhere in Africa were detected as over expressed suggesting a convergence of mechanisms across Sub-Saharan African malaria vectors. The findings give insight into factors that may correlate with pyrethroid PBO LLIN success, broadly supporting model predictions, but revision to guidelines previously issued by the World Health Organization is warranted.

scholarly journals Review and Meta-Analysis of the Evidence for Choosing between Specific Pyrethroids for Programmatic Purposes

Insects ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 826
Author(s):  
Natalie Lissenden ◽  
Mara Kont ◽  
John Essandoh ◽  
Hanafy Ismail ◽  
Thomas Churcher ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Pyrethroid Resistance ◽  
Meta Analysis ◽  
Resistance Management ◽  
Malaria Vectors ◽  
Resistance Testing ◽  
Differential Mortality ◽  
Wild Populations ◽  
Insecticide Resistance Management ◽  
Laboratory Colonies

Pyrethroid resistance is widespread in malaria vectors. However, differential mortality in discriminating dose assays to different pyrethroids is often observed in wild populations. When this occurs, it is unclear if this differential mortality should be interpreted as an indication of differential levels of susceptibility within the pyrethroid class, and if so, if countries should consider selecting one specific pyrethroid for programmatic use over another. A review of evidence from molecular studies, resistance testing with laboratory colonies and wild populations, and mosquito behavioural assays were conducted to answer these questions. Evidence suggested that in areas where pyrethroid resistance exists, different results in insecticide susceptibility assays with specific pyrethroids currently in common use (deltamethrin, permethrin, α-cypermethrin, and λ-cyhalothrin) are not necessarily indicative of an operationally relevant difference in potential performance. Consequently, it is not advisable to use rotation between these pyrethroids as an insecticide-resistance management strategy. Less commonly used pyrethroids (bifenthrin and etofenprox) may have sufficiently different modes of action, though further work is needed to examine how this may apply to insecticide resistance management.

scholarly journals Potential Metabolic Resistance Mechanisms to Ivermectin in Anopheles Gambiae: A Synergist Bioassay Study

2020 ◽  
Author(s):  
Patricia Nicolas ◽  
Caroline Kiuru ◽  
Martin Wagah ◽  
Martha Muturi ◽  
Urs Duthaler ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Anopheles Gambiae ◽  
Control Strategies ◽  
Resistance Mechanisms ◽  
World Health ◽  
Malaria Vectors ◽  
Malaria Vector Control ◽  
Cytochrome P450 Enzymes ◽  
Metabolic Resistance ◽  
Active Efflux

Abstract Background Despite remarkable success obtained with current malaria vector control strategies in the last 15 years, additional innovative measures will be needed to achieve the ambitious goals set for 2030 by the World Health Organization (WHO). New tools will need to address insecticide resistance and residual transmission as key challenges. Endectocides such as ivermectin are drugs that kill mosquitoes which feed on treated subjects. Mass administration of ivermectin can effectively target outdoor and early biting vectors, complementing the still effective conventional tools. Although this approach has garnered attention, development of ivermectin resistance is a potential pitfall. Herein, we evaluate the potential role of xenobiotic pumps and cytochrome P450 enzymes in protecting mosquitoes against ivermectin by active efflux and metabolic detoxification, respectively. Methods We determined the lethal-concentration 50 for ivermectin in colonized Anopheles gambiae, then we used chemical inhibitors and inducers of xenobiotic pumps and cytochrome P450 enzymes in combination with ivermectin to probe the mechanism of ivermectin detoxification. Results Dual inhibition of xenobiotic pumps and cytochromes have a synergistic effect with ivermectin, greatly increasing mosquito mortality. Inhibition of xenobiotic pumps alone had no effect on ivermectin-induced mortality. Induction of xenobiotic pumps and cytochromes may confer partial protection from ivermectin.Conclusion there is a clear pathway for development of ivermectin resistance in malaria vectors. Detoxification mechanisms mediated by cytochrome P450 enzymes are more important than xenobiotic pumps in protecting mosquitoes against ivermectin.

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