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Castañeda S, Adeniyi-Ipadeola G, Wu Y, Suarez-Reyes C, Jain A, Ramírez JD, Weatherhead JE. Characterizing Excretory-Secretory Products Proteome Across Larval Development Stages in Ascaris suum. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.03.601870. [PMID: 39005370 PMCID: PMC11245028 DOI: 10.1101/2024.07.03.601870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Introduction Ascaris lumbricoides and Ascaris suum are parasitic nematodes that primarily infest the small intestines of humans and pigs, respectively. Ascariasis poses a significant threat to human health and swine health. Understanding Ascaris larval development is crucial for developing novel therapeutic interventions that will prevent ascariasis in both humans and pigs. This study aimed to characterize the excretory-secretory (ES) proteome of different Ascaris suum larval stages (L3-egg, L3-lung, L3-trachea) to identify potential targets for intervention to prevent Ascaris -induced global morbidity. Methods Stage-specific larvae were isolated, cultured in vitro and ES-product was collected. Third-stage Ascaris larvae (L3) were isolated from embryonated eggs (L3-egg), isolated from the lungs of Balb/c mice infected with Ascaris suum eggs at day 8 post infection (L3-lungs) and isolated from the trachea of Balb/c mice infected with Ascaris suum eggs at day 12 post infection (L3-trachea). ES products were obtained by culturing larvae. Proteomic analysis was conducted using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and bioinformatic tools including MaxQuant, Perseus, and Andromeda, following a detailed protocol available on GitHub. The analysis encompassed peptide identification, scoring, and quantification against an organism-specific database, with subsequent quality control, correlation assessment, and differential abundance determination using the Amica algorithm. Results A total of 58 unique proteins were identified in the ES products. Fourteen proteins were common across all stages, while others were stage-specific. Principal component analysis revealed distinct protein profiles for each stage, suggesting qualitatively different proteomes. Gene ontology analysis indicated stage-specific GO enrichment of specific protein classes, such as nuclear proteins in L3-egg ES products and metabolic enzymes in L3-lung and L3-trachea ES products. Discussion This study revealed stage-specific differences in the composition of Ascaris ES products. Further investigation into the functional roles of these proteins and their interactions with host cells is crucial for developing novel therapeutic and diagnostic strategies against ascariasis.
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Francisco ME, Watanabe K. Innovative house structures for malaria vector control in Nampula district, Mozambique: assessing mosquito entry prevention, indoor comfort, and community acceptance. Front Public Health 2024; 12:1404493. [PMID: 38894994 PMCID: PMC11183294 DOI: 10.3389/fpubh.2024.1404493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 05/23/2024] [Indexed: 06/21/2024] Open
Abstract
Background Insecticide-treated mosquito bed nets and indoor residual spraying are widely used for malaria vector control. However, their effectiveness can be affected by household members' habits, requiring alternative approaches toward malaria vector control. Objective To assess the effectiveness of modified houses in preventing mosquito entry; to assess the impact of house modifications on indoor air conditions and evaluate the acceptability of modified houses in the community where the study was conducted. Methods Five traditional and five modified houses were constructed in Nampula district, Mozambique and underwent a 90-day overnight indoor mosquito collection using Centers for Disease Control and nitride ultraviolet light traps during the rainy season. Mosquitoes were identified morphologically. Indoor temperature, relative humidity, carbon dioxide levels and wind speed were also collected. The Student's t-test was used to compare the means of the number of mosquitos and environmental factors between both house types. A binomial form of the Generalized Linear Model identified the factors associated with the community volunteer's preference for house type. Results Modified houses reduced the number of Anopheles by an average of 14.97 mosquitos (95% CI, 11.38-18.56, p < 0.000) and non-Anopheles by 16.66 mosquitoes (95% CI, 8.23-25.09, p < 0.000). Although fewer mosquitoes were trapped in modified houses compared to traditional ones, the modifications were more effective against Anopheles (94% reduction) than for non-Anopheles (71% reduction). The average temperature increased at 0.25°C in modified houses but was not statistically significant (95% CI, -0.62 to 0.12, p = 0.181). Community volunteers preferred modified houses due to reduced mosquito buzzing. The efficacy of modified houses including its acceptability by community, highlight its potential to lower malaria risk. Effective integration of modified houses into the vector control strategy will require raising awareness among communities about malaria risks associated with house structure and training them to modify their houses.
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Affiliation(s)
- Micanaldo Ernesto Francisco
- Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, Japan
- Graduate School of Science and Engineering, Ehime University, Matsuyama, Japan
- Faculty of Architecture and Physical Planning (FAPF), Lurio University, Nampula, Mozambique
| | - Kozo Watanabe
- Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, Japan
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Madgwick PG, Tunstall T, Kanitz R. Evolutionary rescue in resistance to pesticides. Proc Biol Sci 2024; 291:20240805. [PMID: 38917864 DOI: 10.1098/rspb.2024.0805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 06/03/2024] [Indexed: 06/27/2024] Open
Abstract
Evolutionary rescue occurs when the genetic evolution of adaptation saves a population from decline or extinction after environmental change. The evolution of resistance to pesticides is a special scenario of abrupt environmental change, where rescue occurs under (very) strong selection for one or a few de novo resistance mutations of large effect. Here, a population genetic model of evolutionary rescue with density-dependent population change is developed, with a focus on deriving results that are important to resistance management. Massive stochastic simulations are used to generate observations, which are accurately predicted using analytical approximations. Key results include the probability density function for the time to resistance and the probability of population extinction. The distribution of resistance times shows a lag period, a narrow peak and a long tail. Surprisingly, the mean time to resistance can increase with the strength of selection because, if a mutation does not occur early on, then its emergence is delayed by the pesticide reducing the population size. The probability of population extinction shows a sharp transition, in that when extinction is possible, it is also highly likely. Consequently, population suppression and (local) eradication can be theoretically achievable goals, as novel strategies to delay resistance evolution.
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Affiliation(s)
- Philip G Madgwick
- Syngenta, Jealott's Hill International Research Centre , Bracknell RG42 6EY, UK
| | - Thomas Tunstall
- Living Systems Institute, University of Exeter , Exeter EX4 4PY, UK
| | - Ricardo Kanitz
- Syngenta Crop Protection, Rosentalstrasse 67 , Basel CH-4058, Switzerland
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Cushing JM, Park J, Farrell A, Chitnis N. Treatment outcome in an SI model with evolutionary resistance: a Darwinian model for the evolution of resistance. JOURNAL OF BIOLOGICAL DYNAMICS 2023; 17:2255061. [PMID: 37733402 DOI: 10.1080/17513758.2023.2255061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 08/30/2023] [Indexed: 09/22/2023]
Abstract
We consider a Darwinian (evolutionary game theoretic) version of a standard susceptible-infectious SI model in which the resistance of the disease causing pathogen to a treatment that prevents death to infected individuals is subject to evolutionary adaptation. We determine the existence and stability of all equilibria, both disease-free and endemic, and use the results to determine conditions under which the treatment will succeed or fail. Of particular interest are conditions under which a successful treatment in the absence of resistance adaptation (i.e. one that leads to a stable disease-free equilibrium) will succeed or fail when pathogen resistance is adaptive. These conditions are determined by the relative breadths of treatment effectiveness and infection transmission rate distributions as functions of pathogen resistance.
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Affiliation(s)
- J M Cushing
- Department of Mathematics, University of Arizona, Interdisciplinary Program in Applied Mathematics, Tucson, AZ, USA
| | - Junpyo Park
- Department of Applied Mathematics, College of Applied Science, Kyung Hee University, Yongin, Republic of Korea
| | - Alex Farrell
- Caris Life Sciences, Phoenix, AZ, USA
- Department of Mathematics, University of Arizona, Tucson, AZ, USA
| | - Nakul Chitnis
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
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Giordano R, Weber EP, Mitacek R, Flores A, Ledesma A, De AK, Herman TK, Soto-Adames FN, Nguyen MQ, Hill CB, Hartman GL. Patterns of asexual reproduction of the soybean aphid, Aphis glycines (Matsumura), with and without the secondary symbionts Wolbachia and Arsenophonus, on susceptible and resistant soybean genotypes. Front Microbiol 2023; 14:1209595. [PMID: 37720159 PMCID: PMC10501154 DOI: 10.3389/fmicb.2023.1209595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 07/25/2023] [Indexed: 09/19/2023] Open
Abstract
Plant breeding is used to develop crops with host resistance to aphids, however, virulent biotypes often develop that overcome host resistance genes. We tested whether the symbionts, Arsenophonus (A) and Wolbachia (W), affect virulence and fecundity in soybean aphid biotypes Bt1 and Bt3 cultured on whole plants and detached leaves of three resistant, Rag1, Rag2 and Rag1 + 2, and one susceptible, W82, soybean genotypes. Whole plants and individual aphid experiments of A. glycines with and without Arsenophonus and Wolbachia did not show differences in overall fecundity. Differences were observed in peak fecundity, first day of deposition, and day of maximum nymph deposition of individual aphids on detached leaves. Bt3 had higher fecundity than Bt1 on detached leaves of all plant genotypes regardless of bacterial profile. Symbionts did not affect peak fecundity of Bt1 but increased it in Bt3 (A+W+) and all Bt3 strains began to deposit nymphs earlier than the Bt1 (A+W-). Arsenophonus in Bt1 delayed the first day of nymph deposition in comparison to aposymbiotic Bt1 except when reared on Rag1 + 2. For the Bt1 and Bt3 strains, symbionts did not result in a significant difference in the day they deposited the maximum number of nymphs nor was there a difference in survival or variability in number of nymphs deposited. Variability of number of aphids deposited was higher in aphids feeding on resistant plant genotypes. The impact of Arsenophonus on soybean aphid patterns of fecundity was dependent on the aphid biotype and plant genotype. Wolbachia alone had no detectable impact but may have contributed to the increased fecundity of Bt3 (A+W+). An individual based model, using data from the detached leaves experiment and with intraspecific competition removed, found patterns similar to those observed in the greenhouse and growth chamber experiments including a significant interaction between soybean genotype and aphid strain. Combining individual data with the individual based model of population growth isolated the impact of fecundity and host resistance from intraspecific competition and host health. Changes to patterns of fecundity, influenced by the composition and concentration of symbionts, may contribute to competitive interactions among aphid genotypes and influence selection on virulent aphid populations.
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Affiliation(s)
- Rosanna Giordano
- Institute of Environment, Florida International University, Miami, FL, United States
- Puerto Rico Science Technology and Research Trust, San Juan, Puerto Rico
| | - Everett P. Weber
- Office of Institutional Research, Dartmouth College, Hanover, NH, United States
| | - Ryan Mitacek
- Department of Crop Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Alejandra Flores
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Alonso Ledesma
- College of Agricultural, Consumer and Environmental Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Arun K. De
- Animal Sciences Division, ICAR-Central Island Agricultural Research Institute, Port Blair, India
| | | | - Felipe N. Soto-Adames
- Division of Plant Industry, Florida Department of Agriculture and Consumer Services, Gainesville, FL, United States
| | - Minh Q. Nguyen
- Neochromosome, Inc., Long Island City, NY, United States
| | - Curtis B. Hill
- Neochromosome, Inc., Long Island City, NY, United States
| | - Glen L. Hartman
- Department of Crop Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States
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Ang S, Cao N, Zheng W, Zhang Z, Li J, Yan Z, Su K, Wong WL, Zhang K, Hong WD, Wu P. Novel Sophoridine Derivatives as Potential Larvicidal Agents against Aedes albopictus: Synthesis, Biological Evaluation, Acetylcholinesterase Inhibition, and Morphological Study. INSECTS 2023; 14:399. [PMID: 37103214 PMCID: PMC10140878 DOI: 10.3390/insects14040399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/18/2023] [Accepted: 04/19/2023] [Indexed: 06/19/2023]
Abstract
Two series of novel sophoridine derivatives were designed, synthesized, and evaluated for their anti-mosquito activity. SOP-2g, SOP-2q, and SOP-2r exhibited potential larvicidal activity against Aedes albopictus larva with LC50 values of 330.98, 430.53, and 411.09 ppm, respectively. Analysis of structure-activity relationships indicated that the oxime ester group was beneficial for improving the larvicidal biological activity, whereas the long-chain aliphatic group and fused-ring group were introduced. Furthermore, the larvicidal mechanism was also investigated based on the inhibition assay of acetylcholinesterase (AChE) and the morphological observation of dead larva treated with derivatives. Results indicated that the AChE inhibitory activity of the preferred three derivatives were 63.16%, 46.67%, and 35.11%, respectively, at 250 ppm concentration. Additionally, morphological evidence demonstrated that SOP-2q and SOP-2r induced changes in the larva's intestinal cavity, caudal gill, and tail, thereby displaying larvicidal action against Ae. albopictus together with AChE inhibition. Therefore, this study implied that sophoridine and its novel derivatives could be used to control the population of mosquito larva, which may also be effective alkaloids to reduce the mosquito population density.
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Affiliation(s)
- Song Ang
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, China (W.Z.); (K.Z.)
- International Healthcare Innovation Institute (Jiangmen), Jiangmen 529040, China
| | - Nana Cao
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, China (W.Z.); (K.Z.)
- International Healthcare Innovation Institute (Jiangmen), Jiangmen 529040, China
| | - Wende Zheng
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, China (W.Z.); (K.Z.)
- International Healthcare Innovation Institute (Jiangmen), Jiangmen 529040, China
| | - Zhen Zhang
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, China (W.Z.); (K.Z.)
- International Healthcare Innovation Institute (Jiangmen), Jiangmen 529040, China
| | - Jinxuan Li
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, China (W.Z.); (K.Z.)
- International Healthcare Innovation Institute (Jiangmen), Jiangmen 529040, China
| | - Zhenping Yan
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, China (W.Z.); (K.Z.)
- International Healthcare Innovation Institute (Jiangmen), Jiangmen 529040, China
| | - Kaize Su
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, China (W.Z.); (K.Z.)
- International Healthcare Innovation Institute (Jiangmen), Jiangmen 529040, China
| | - Wing-Leung Wong
- The State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Kun Zhang
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, China (W.Z.); (K.Z.)
- International Healthcare Innovation Institute (Jiangmen), Jiangmen 529040, China
| | - Weiqian David Hong
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, China (W.Z.); (K.Z.)
- International Healthcare Innovation Institute (Jiangmen), Jiangmen 529040, China
| | - Panpan Wu
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, China (W.Z.); (K.Z.)
- International Healthcare Innovation Institute (Jiangmen), Jiangmen 529040, China
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Ngonghala CN. Assessing the impact of insecticide-treated nets in the face of insecticide resistance on malaria control. J Theor Biol 2022; 555:111281. [PMID: 36154815 DOI: 10.1016/j.jtbi.2022.111281] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 09/01/2022] [Accepted: 09/17/2022] [Indexed: 01/14/2023]
Abstract
The mosquito-borne disease, malaria, continues to impose a devastating health and economic burden worldwide. In malaria-endemic areas, insecticide-treated nets (ITNs) have been useful in curtailing the burden of the disease. However, mosquito resistance to insecticides, decay in ITN efficacy, net attrition, etc., undermine the effectiveness of ITNs in combatting malaria. In this study, mathematical models that account for asymptomatic infectious humans (through a partially immune class or a separate asymptomatic infectious class), insecticide resistance, and decay in ITN efficacy are proposed and analyzed. Analytical and numerical results of the models when ITN efficacy is constant show that there are parameter regimes for which a backward bifurcation occurs. Local and global sensitivity analyses are performed to identify parameters (some of which are potential targets for disease control) with the most significant influence on the control reproduction (Rc) and disease prevalence. These influential parameters include the maximum biting rate of resistant mosquitoes, ITN coverage, initial ITN efficacy against sensitive mosquitoes, the probability that an infectious mosquito (human) infects a susceptible human (mosquito), and the rate at which adult mosquitoes develop (lose) resistance to insecticides. Simulations of the models show that accounting for asymptomatic infectious humans through a separate class, or not accounting for the decay in ITN efficacy leads to an underestimation of disease burden. In particular, if the initial efficacy of ITNs against sensitive and resistance mosquitoes is 96%, the minimum ITN coverage required to reduce Rc below one (and hence, contain malaria) is approximately 11% (27%) lower when ITN efficacy is averaged (constant) for a model with a separate asymptomatic class. For the model with a partially immune class and decaying ITN efficacy, reducing Rc below one is impossible even if the entire populace uses ITNs. The study shows that replacing ITNs before their prescribed lifespans, or designing ITNs with longer lifespans is important for malaria control. Furthermore, the study shows that piperonyl butoxide (PBO) ITNs (which inhibit or reverse insecticide resistance) outperform regular ITNs in malaria control. Hence, prospects for effectively controlling malaria are enhanced by widespread use of high quality ITNs (e.g. PBO ITNs), especially if the useful lifespans of the ITNs are long enough and the ITNs are replaced before the end of their useful lifespans.
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Affiliation(s)
- Calistus N Ngonghala
- Department of Mathematics, University of Florida, 1400 Stadium Rd, Gainesville, FL 32611, United States of America; Emerging Pathogens Institute, University of Florida, 2055 Mowry Rd, Gainesville, FL 32610, United States of America; Center for African Studies, University of Florida, 427 Grinter Hall 1523 Union Rd, Gainesville, FL 32611, United States of America.
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Brozak SJ, Mohammed-Awel J, Gumel AB. Mathematics of a single-locus model for assessing the impacts of pyrethroid resistance and temperature on population abundance of malaria mosquitoes. Infect Dis Model 2022; 7:277-316. [PMID: 35782338 PMCID: PMC9234087 DOI: 10.1016/j.idm.2022.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/25/2022] [Accepted: 05/25/2022] [Indexed: 11/18/2022] Open
Abstract
This study presents a genetic-ecology modeling framework for assessing the combined impacts of insecticide resistance, temperature variability, and insecticide-based interventions on the population abundance and control of malaria mosquitoes by genotype. Rigorous analyses of the model we developed reveal that the boundary equilibrium with only mosquitoes of homozygous sensitive (resistant) genotype is locally-asymptotically stable whenever a certain ecological threshold, denoted by R0SS(R0RR), is less than one. Furthermore, genotype i drives genotype j to extinction whenever R0j>1 and R0i<1 (where i, j = SS or RR, with i ≠ j). The model exhibits the phenomenon of bistability when both thresholds are less than one. In such a bistable situation, convergence to any of the two boundary equilibria depends on the initial allele distribution in the state variables of the model. Furthermore, in this bistable case, where max{R0SS,R0RR}<1, the basin of attraction of the boundary equilibrium of the mosquito genotype with lower value of the ecological threshold is larger. Specifically, the basin of attraction of the boundary equilibrium for genotype i is larger than that of genotype j if R0i<R0j<1. When both ecological thresholds exceed one (min{R0SS,R0RR}>1), the two boundary equilibria lose their stability, and a coexistence equilibrium (where all three mosquito genotypes coexist) becomes locally-asymptotically stable. Global sensitivity analysis shows that the key parameters that greatly influence the dynamics and population abundance of resistant mosquitoes include the proportion of new adult mosquitoes that are females, the insecticide-induced mortality rate of adult female mosquitoes, the coverage level and efficacy of adulticides used in the community, the oviposition rates for eggs of heterozygous and homozygous resistant genotypes, and the modification parameter accounting for the reduction in insecticide-induced mortality due to resistance. Numerical simulations show that the adult mosquito population increases with increasing temperature until a peak is reached at 31 °C, and declines thereafter. Simulating the model for moderate and high adulticide coverage, together with varying fitness costs of resistance, shows a switch in the dominant genotype at equilibrium as temperature is varied. In other words, this study shows that, for certain combinations of adulticide coverage and fitness costs of insecticide resistance, increases in temperature could result in effective management of resistance (by causing the switch from a stable resistant-only boundary equilibrium (at 18 °C) to a stable sensitive-only boundary equilibrium (at 25 °C)). Finally, this study shows that, for moderate fitness costs of resistance, density-dependent larval mortality suppresses the total population of adult mosquitoes with the resistant allele for all temperature values in the range [18 °C–36 °C].
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Affiliation(s)
- Samantha J. Brozak
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Jemal Mohammed-Awel
- Department of Mathematics, Morgan State University, Baltimore, MD, 21251, USA
| | - Abba B. Gumel
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, 85287, USA
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
- Department of Mathematics and Applied Mathematics, University of Pretoria, Pretoria, 0002, South Africa
- Corresponding author. School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, 85287, USA.
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Juache-Villagrana AE, Pando-Robles V, Garcia-Luna SM, Ponce-Garcia G, Fernandez-Salas I, Lopez-Monroy B, Rodriguez-Sanchez IP, Flores AE. Assessing the Impact of Insecticide Resistance on Vector Competence: A Review. INSECTS 2022; 13:377. [PMID: 35447819 PMCID: PMC9024519 DOI: 10.3390/insects13040377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/07/2022] [Accepted: 04/11/2022] [Indexed: 01/09/2023]
Abstract
The primary strategy to avoid adverse impacts from insect-mediated pathogen transmission is the chemical control of vector populations through insecticides; its continued use has led to insecticide resistance and unknown consequences on vector competence. This review aims to systematically analyze and synthesize the research on the influence of insecticide resistance (IR) on vector competence (VC). Thirty studies met the inclusion criteria. Twenty studies, conducted either in laboratory or field settings, described the influence of phenotypic insecticide resistance and mechanisms on VC in vectors of human pathogens. Seven studies showed the effect of exposure to insecticides on VC in vectors of human pathogens. Three studies reported the influence of phenotypic resistance and mechanisms on VC in crop pests. The evidence shows that IR could enhance, impair, or have no direct effect on VC in either field or laboratory-designed studies. Similar positive and negative trends are found in pest vectors in crops and studies of insecticide exposure and VC. Even though there is evidence that exposure to insecticides and IR can enhance VC, thus increasing the risk of pathogen transmission, more investigations are needed to confirm the observed patterns and what implications these factors could have in vector control programs.
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Affiliation(s)
- Alan E. Juache-Villagrana
- Facultad de Ciencias Biologicas, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n Cd. Universitaria, San Nicolas de los Garza 66455, Nuevo Leon, Mexico; (A.E.J.-V.); (S.M.G.-L.); (G.P.-G.); (I.F.-S.); (B.L.-M.); (I.P.R.-S.)
| | - Victoria Pando-Robles
- Centro de Investigacion Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Publica, Cuernavaca 62100, Morelos, Mexico;
| | - Selene M. Garcia-Luna
- Facultad de Ciencias Biologicas, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n Cd. Universitaria, San Nicolas de los Garza 66455, Nuevo Leon, Mexico; (A.E.J.-V.); (S.M.G.-L.); (G.P.-G.); (I.F.-S.); (B.L.-M.); (I.P.R.-S.)
| | - Gustavo Ponce-Garcia
- Facultad de Ciencias Biologicas, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n Cd. Universitaria, San Nicolas de los Garza 66455, Nuevo Leon, Mexico; (A.E.J.-V.); (S.M.G.-L.); (G.P.-G.); (I.F.-S.); (B.L.-M.); (I.P.R.-S.)
| | - Ildefonso Fernandez-Salas
- Facultad de Ciencias Biologicas, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n Cd. Universitaria, San Nicolas de los Garza 66455, Nuevo Leon, Mexico; (A.E.J.-V.); (S.M.G.-L.); (G.P.-G.); (I.F.-S.); (B.L.-M.); (I.P.R.-S.)
| | - Beatriz Lopez-Monroy
- Facultad de Ciencias Biologicas, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n Cd. Universitaria, San Nicolas de los Garza 66455, Nuevo Leon, Mexico; (A.E.J.-V.); (S.M.G.-L.); (G.P.-G.); (I.F.-S.); (B.L.-M.); (I.P.R.-S.)
| | - Iram P. Rodriguez-Sanchez
- Facultad de Ciencias Biologicas, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n Cd. Universitaria, San Nicolas de los Garza 66455, Nuevo Leon, Mexico; (A.E.J.-V.); (S.M.G.-L.); (G.P.-G.); (I.F.-S.); (B.L.-M.); (I.P.R.-S.)
| | - Adriana E. Flores
- Facultad de Ciencias Biologicas, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n Cd. Universitaria, San Nicolas de los Garza 66455, Nuevo Leon, Mexico; (A.E.J.-V.); (S.M.G.-L.); (G.P.-G.); (I.F.-S.); (B.L.-M.); (I.P.R.-S.)
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Barreaux P, Koella JC, N'Guessan R, Thomas MB. Use of novel lab assays to examine the effect of pyrethroid-treated bed nets on blood-feeding success and longevity of highly insecticide-resistant Anopheles gambiae s.l. mosquitoes. Parasit Vectors 2022; 15:111. [PMID: 35346334 PMCID: PMC8962112 DOI: 10.1186/s13071-022-05220-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Accepted: 02/24/2022] [Indexed: 11/28/2022] Open
Abstract
Background There is a pressing need to improve understanding of how insecticide resistance affects the functional performance of insecticide-treated nets (ITNs). Standard WHO insecticide resistance monitoring assays are designed for resistance surveillance and do not necessarily provide insight into how different frequencies, mechanisms or intensities of resistance affect the ability of ITNs to reduce malaria transmission. Methods The current study presents some novel laboratory-based assays that attempt to better simulate realistic exposure of mosquitoes to ITNs and to quantify impact of exposure not only on instantaneous mortality, but also on blood-feeding and longevity, two traits that are central to transmission. The assays evaluated the performance of a standard ITN (Permanet® 2.0; Vestergaard Frandsen), a ‘next generation’ combination ITN with a resistance-breaking synergist (Permanet® 3.0) and an untreated net (UTN), against field-derived Anopheles gambiae sensu lato mosquitoes from Côte d’Ivoire exhibiting a 1500-fold increase in pyrethroid resistance relative to a standard susceptible strain. Results The study revealed that the standard ITN induced negligible instantaneous mortality against the resistant mosquitoes, whereas the resistance-breaking net caused high mortality and a reduction in blood-feeding. However, both ITNs still impacted long-term survival relative to the UTN. The impact on longevity depended on feeding status, with blood-fed mosquitoes living longer than unfed mosquitoes following ITN exposure. Exposure to both ITNs also reduced the blood-feeding success, the time spent on the net and blood-feeding duration, relative to the untreated net. Conclusion Although a standard ITN did not have as substantial instantaneous impact as the resistance-breaking net, it still had significant impacts on traits important for transmission. These results highlight the benefit of improved bioefficacy assays that allow for realistic exposure and consider sub- or pre-lethal effects to help assess the functional significance of insecticide resistance. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05220-y.
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Affiliation(s)
- Priscille Barreaux
- Liverpool School of Tropical Medicine, Liverpool, UK. .,Pennsylvania State University, State College, PA, USA. .,University of Neuchâtel, Neuchâtel, Switzerland.
| | | | - Raphael N'Guessan
- London School of Tropical Medicine, London, UK.,Vector Control Product Evaluation Centre, Institute Pierre Richet, Bouaké, Côte d'Ivoire
| | - Matthew B Thomas
- Pennsylvania State University, State College, PA, USA.,University of York, York, UK
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11
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Li X, Hu S, Zhang H, Yin H, Wang H, Zhou D, Sun Y, Ma L, Shen B, Zhu C. MiR-279-3p regulates deltamethrin resistance through CYP325BB1 in Culex pipiens pallens. Parasit Vectors 2021; 14:528. [PMID: 34641939 PMCID: PMC8507342 DOI: 10.1186/s13071-021-05033-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 09/23/2021] [Indexed: 11/15/2022] Open
Abstract
Background The overuse of insecticides to control insect vectors has promoted extensive insecticide resistance in mosquitoes. In this study, the functions of microRNA (miR)-279-3p and its target CYP325BB1 in the regulation of deltamethrin resistance in Culex pipiens pallens was investigated. Methods Quantitative real-time reverse transcription PCR was used to detect the expression levels of miR-279-3p and CYP325BB1. Then, the dual-luciferase reporter assay system, RNA interference, CDC bottle bioassay and Cell Counting Kit-8 (CCK-8) assay were used to explore the roles of these molecules in deltamethrin resistance both in vivo and in vitro. Results The expression patterns of miR-279-3p and CYP325BB1 were compared between deltamethrin-sensitive (DS-strain) and deltamethrin-resistant (DR-strain) mosquitoes. Luciferase activity was downregulated by miR-279-3p, the effect of which was ablated by a mutation of the putative binding site for CYP325BB1. In DR-strain mosquitoes, the expression of miR-279-3p was increased by microinjection and oral feeding of miR-279-3p agomir (mimic). CYP325BB1 mRNA levels were downregulated, which resulted in a higher mortality of the mosquitoes in miR-279-3p mimic-treated groups. In the DS-strain mosquitoes, microinjection of a miR-279-3p inhibitor decreased miR-279-3p expression, whereas the expression of CYP325BB1 was increased; the mortality of these mosquitoes decreased significantly. In addition, overexpression of pIB/V5-His-CYP325BB1 changed the sensitivity of C6/36 cells to deltamethrin in vitro. Also in DR-strain mosquitoes, downregulation of CYP325BB1 expression by microinjection of si-CYP325BB1 increased mosquito mortality in vivo. Conclusions These findings provide empirical evidence of the involvement of miRNAs in the regulation of insecticide resistance and indicate that miR-279-3p suppresses the expression of CYP325BB1, which in turn decreases deltamethrin resistance, resulting in increased mosquito mortality. Taken together, the results provide important information for use in the development of future mosquito control strategies. Graphical abstract ![]()
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Affiliation(s)
- Xixi Li
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 211166, People's Republic of China.,Department of Pathogen Biology, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, 210046, People's Republic of China
| | - Shengli Hu
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 211166, People's Republic of China.,Department of Stomatology, Fifty People's Hospital of Yuhang District, Hangzhou, Zhejiang, 311199, People's Republic of China
| | - Hongbo Zhang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 211166, People's Republic of China
| | - Haitao Yin
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 211166, People's Republic of China
| | - Huan Wang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 211166, People's Republic of China
| | - Dan Zhou
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 211166, People's Republic of China
| | - Yan Sun
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 211166, People's Republic of China
| | - Lei Ma
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 211166, People's Republic of China
| | - Bo Shen
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 211166, People's Republic of China.
| | - Changliang Zhu
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 211166, People's Republic of China
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12
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Richoux GM, Yang L, Norris E, Jiang S, Linthicum KJ, Bloomquist JR. Resistance-Breaking Insecticidal Activity of New Spatial Insecticides against Aedes aegypti. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:9684-9692. [PMID: 34387470 DOI: 10.1021/acs.jafc.1c01200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The use of N-aryl amide derivatives as spatially acting insecticides remains relatively unexplored. To expand this knowledge, we synthesized eighty-nine N-aryl amide analogues and screened them for mortality against an insecticide-susceptible strain of Aedes aegypti mosquitoes, Orlando (OR), using a vapor exposure glass tube assay. Of the screened compounds, twenty-two produced >92% mortality at 24 h and warranted further investigation to determine LC50 values. Fifteen of these analogues had LC50 values within 2 orders of magnitude of transfluthrin, and of significant interest, N-(2,6-dichloro-4-(trifluoromethyl)phenyl)-2,2,3,3,3-pentafluoropropanamide (compound 70) was nearly as potent as transfluthrin and exhibited greater toxicity than metofluthrin when screened against OR A. aegypti. Compounds exhibiting potent toxicity against OR A. aegypti or whose structure-activity relationship potentially offered beneficial insights into structure optimization were screened against the insecticide-resistant, Puerto Rico (PR), strain of A. Aegypti, and it was discovered that not only did these N-arylamides typically show little resistance, some such as N-(2,6-dichloropyridin-4-yl)-2,2,3,3,4,4,4-heptafluorobutanamide (compound 36) and 2,2,3,3,4,4,4-heptafluoro-N-(3,4,5-trifluorophenyl)butanamide (compound 40) were actually more potent against the PR mosquitoes. Due to this promising insecticidal activity, five compounds were administered orally to mice to determine acute oral rodent toxicity. All five compounds were found to have mouse oral toxicity LD50 values well above the minimum safe level as set by the Innovative Vector Control Consortium (50 mg/kg). In addition to the promising biological activity documented here, we report the structure-activity relationship analysis used to guide the derivatization approach taken and to further inform future efforts in the development of N-arylamides as potential resistance-breaking, spatially acting insecticides.
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Affiliation(s)
- Gary M Richoux
- Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, Florida 32610, United States
| | - Liu Yang
- Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, Florida 32610, United States
| | - Edmund Norris
- Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, Florida 32610, United States
- Agricultural and Veterinary Entomology, USDA, ARS, Center for Medical, Gainesville, Florida 32608, United States
| | - Shiyao Jiang
- Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, Florida 32610, United States
| | - Kenneth J Linthicum
- Agricultural and Veterinary Entomology, USDA, ARS, Center for Medical, Gainesville, Florida 32608, United States
| | - Jeffrey R Bloomquist
- Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, Florida 32610, United States
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13
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Runge M, Mapua S, Nambunga I, Smith TA, Chitnis N, Okumu F, Pothin E. Evaluation of different deployment strategies for larviciding to control malaria: a simulation study. Malar J 2021; 20:324. [PMID: 34315473 PMCID: PMC8314573 DOI: 10.1186/s12936-021-03854-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 07/16/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Larviciding against malaria vectors in Africa has been limited to indoor residual spraying and insecticide-treated nets, but is increasingly being considered by some countries as a complementary strategy. However, despite progress towards improved larvicides and new tools for mapping or treating mosquito-breeding sites, little is known about the optimal deployment strategies for larviciding in different transmission and seasonality settings. METHODS A malaria transmission model, OpenMalaria, was used to simulate varying larviciding strategies and their impact on host-seeking mosquito densities, entomological inoculation rate (EIR) and malaria prevalence. Variations in coverage, duration, frequency, and timing of larviciding were simulated for three transmission intensities and four transmission seasonality profiles. Malaria transmission was assumed to follow rainfall with a lag of one month. Theoretical sub-Saharan African settings with Anopheles gambiae as the dominant vector were chosen to explore impact. Relative reduction compared to no larviciding was predicted for each indicator during the simulated larviciding period. RESULTS Larviciding immediately reduced the predicted host-seeking mosquito densities and EIRs to a maximum that approached or exceeded the simulated coverage. Reduction in prevalence was delayed by approximately one month. The relative reduction in prevalence was up to four times higher at low than high transmission. Reducing larviciding frequency (i.e., from every 5 to 10 days) resulted in substantial loss in effectiveness (54, 45 and 53% loss of impact for host-seeking mosquito densities, EIR and prevalence, respectively). In seasonal settings the most effective timing of larviciding was during or at the beginning of the rainy season and least impactful during the dry season, assuming larviciding deployment for four months. CONCLUSION The results highlight the critical role of deployment strategies on the impact of larviciding. Overall, larviciding would be more effective in settings with low and seasonal transmission, and at the beginning and during the peak densities of the target species populations. For maximum impact, implementers should consider the practical ranges of coverage, duration, frequency, and timing of larviciding in their respective contexts. More operational data and improved calibration would enable models to become a practical tool to support malaria control programmes in developing larviciding strategies that account for the diversity of contexts.
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Affiliation(s)
- Manuela Runge
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Salum Mapua
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Ismail Nambunga
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Thomas A Smith
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Nakul Chitnis
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Fredros Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Emilie Pothin
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland.,Clinton Health Access Initiative, Boston, USA
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14
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NGONGHALA CALISTUSN, WAIRIMU JOSEPHINE, ADAMSKI JESSE, DESAI HARDIK. IMPACT OF ADAPTIVE MOSQUITO BEHAVIOR AND INSECTICIDE-TREATED NETS ON MALARIA PREVALENCE. J BIOL SYST 2020. [DOI: 10.1142/s0218339020400100] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Malaria prevalence in sub-Saharan Africa remains high. Kenya for example, records about 3.5 million new cases and 11 thousand deaths each year.1 Most of these cases and deaths are among children under five. The main control method in malaria endemic regions has been through the use of insecticide-treated nets (ITNs). Although this approach has been fairly successful, the gains are threatened by mosquito-resistance to pyrethroids (insecticides on nets), physical and chemical degradation of ITNs that reduce their efficacy, inconsistent and improper use by humans, etc. We present a model to investigate the effects of ITN use and mosquito-resistance and adaptation to pyrethroids used to treat bed nets on malaria prevalence and control in malaria endemic regions. The model captures the development and loss of resistance to insecticides, the effects of ITN use on malaria control in a setting where proper and consistent use is not guaranteed, as well as differentiated biting of human hosts by resistant and sensitive mosquitoes. Important thresholds, including the basic reproduction number [Formula: see text], and two parameter groupings that are important for disease control and for establishing the existence of endemic equilibria to the model are calculated. Furthermore, a global sensitivity analysis is carried out to identify important parameters such as insecticide treated bed-net coverage, ITN, the maximum biting rate of resistant mosquitoes, etc., that drive the system and that can be targeted for disease control. Threshold levels of ITN coverage and ITN efficacy required for containing the disease are identified and shown to depend on the type of insecticide-resistance. For example, when mosquito-resistance to insecticides is not permanent and is acquired only through recruitment and the efficacy of ITNs is [Formula: see text], about [Formula: see text] net coverage is required to contain malaria. However, for the same ITN efficacy, i.e., [Formula: see text], approximately [Formula: see text] net coverage is required to contain the disease when resistance to insecticides is permanent and is acquired through recruitment and mutation in mosquitoes. The model exhibits a backward bifurcation, which implies that simply reducing [Formula: see text] slightly below unity might not be enough to contain the disease. We conclude that appropriate measures to reduce or eliminate mosquito-resistance to insecticides, ensure that more people in endemic areas own and use ITNs properly, and that the efficacy of these nets remain high most of the time, as well as educating populations in malaria endemic areas on how to keep mosquito densities low and minimize mosquito bites are important for containing malaria.
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Affiliation(s)
- CALISTUS N. NGONGHALA
- Department of Mathematics, University of Florida, Gainesville, FL 32611, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32608, USA
| | | | - JESSE ADAMSKI
- Department of Mathematics, University of Florida, Gainesville, FL 32611, USA
| | - HARDIK DESAI
- Department of Mathematics, University of Florida, Gainesville, FL 32611, USA
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15
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Selvaraj P, Wenger EA, Bridenbecker D, Windbichler N, Russell JR, Gerardin J, Bever CA, Nikolov M. Vector genetics, insecticide resistance and gene drives: An agent-based modeling approach to evaluate malaria transmission and elimination. PLoS Comput Biol 2020; 16:e1008121. [PMID: 32797077 PMCID: PMC7449459 DOI: 10.1371/journal.pcbi.1008121] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 08/26/2020] [Accepted: 07/02/2020] [Indexed: 12/19/2022] Open
Abstract
Vector control has been a key component in the fight against malaria for decades, and chemical insecticides are critical to the success of vector control programs worldwide. However, increasing resistance to insecticides threatens to undermine these efforts. Understanding the evolution and propagation of resistance is thus imperative to mitigating loss of intervention effectiveness. Additionally, accelerated research and development of new tools that can be deployed alongside existing vector control strategies is key to eradicating malaria in the near future. Methods such as gene drives that aim to genetically modify large mosquito populations in the wild to either render them refractory to malaria or impair their reproduction may prove invaluable tools. Mathematical models of gene flow in populations, which is the transfer of genetic information from one population to another through migration, can offer invaluable insight into the behavior and potential impact of gene drives as well as the spread of insecticide resistance in the wild. Here, we present the first multi-locus, agent-based model of vector genetics that accounts for mutations and a many-to-many mapping cardinality of genotypes to phenotypes to investigate gene flow, and the propagation of gene drives in Anopheline populations. This model is embedded within a large scale individual-based model of malaria transmission representative of a high burden, high transmission setting characteristic of the Sahel. Results are presented for the selection of insecticide-resistant vectors and the spread of resistance through repeated deployment of insecticide treated nets (ITNs), in addition to scenarios where gene drives act in concert with existing vector control tools such as ITNs. The roles of seasonality, spatial distribution of vector habitat and feed sites, and existing vector control in propagating alleles that confer phenotypic traits via gene drives that result in reduced transmission are explored. The ability to model a spectrum of vector species with different genotypes and phenotypes in the context of malaria transmission allows us to test deployment strategies for existing interventions that reduce the deleterious effects of resistance and allows exploration of the impact of new tools being proposed or developed.
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Affiliation(s)
- Prashanth Selvaraj
- Institute for Disease Modeling, Bellevue, Washington, United States of America
| | - Edward A. Wenger
- Institute for Disease Modeling, Bellevue, Washington, United States of America
| | - Daniel Bridenbecker
- Institute for Disease Modeling, Bellevue, Washington, United States of America
| | - Nikolai Windbichler
- Department of Life Sciences, Imperial College London, South Kensington, United Kingdom
| | - Jonathan R. Russell
- Institute for Disease Modeling, Bellevue, Washington, United States of America
| | - Jaline Gerardin
- Institute for Disease Modeling, Bellevue, Washington, United States of America
- Department of Preventive Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Caitlin A. Bever
- Institute for Disease Modeling, Bellevue, Washington, United States of America
| | - Milen Nikolov
- Institute for Disease Modeling, Bellevue, Washington, United States of America
- Sage Bionetworks, Seattle, Washington, United States of America
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16
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Mohammed-Awel J, Iboi EA, Gumel AB. Insecticide resistance and malaria control: A genetics-epidemiology modeling approach. Math Biosci 2020; 325:108368. [PMID: 32437715 DOI: 10.1016/j.mbs.2020.108368] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/19/2020] [Accepted: 04/29/2020] [Indexed: 11/25/2022]
Abstract
Malaria, a deadly infectious disease caused by the protozoan Plasmodium, remains a major public health menace affecting at least half the human race. Although the large-scale usage of insecticides-based control measures, notably long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), have led to a dramatic reduction of the burden of this global scourge between the period 2000 to 2015, the fact that the malaria vector (adult female Anopheles mosquito) has become resistant to all currently-available insecticides potentially makes the current laudable global effort to eradicate malaria by 2040 more challenging. This study presents a novel mathematical model, which couples malaria epidemiology with mosquito population genetics, for assessing the impact of insecticides resistance on malaria epidemiology. Numerical simulations of the model, using data relevant to malaria transmission dynamics in the Jimma Zone of Southwestern Ethiopia, show that the implementation of a control strategy based on using LLINs alone can lead to the effective control of malaria, while also effectively managing insecticide resistance, if the LLINs coverage in the community is high enough (over 90%). It is further shown that combining LLINs with IRS (both at reduced and realistically-attainable coverage levels) can lead to the aforementioned effective control of malaria and effective management of insecticide resistance if their coverage levels lie within a certain effective control window in the LLINs-IRS coverage parameter space (this result generally holds regardless of whether or not larviciding is implemented in the community). The study identifies three key parameters of the model that negatively affect the size of the effective control window, namely parameters related with the coverage level of larviciding, the number of new adult mosquitoes that are females and the initial size of the frequency of resistant allele in the community. For the coverage of LLINs and IRS within the effective control window, an additional increase in the values of the aforementioned three parameters may lead to a shrinkage in the size of the effective control window (thereby causing the failure of the insecticides-based control).
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Affiliation(s)
- Jemal Mohammed-Awel
- Department of Mathematics, Valdosta State University, Valdosta, GA 31698, USA.
| | - Enahoro A Iboi
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Abba B Gumel
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, 85287, USA
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17
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Modelling the control of Aedes albopictus mosquitoes based on sterile males release techniques in a tropical environment. Ecol Modell 2020. [DOI: 10.1016/j.ecolmodel.2020.109002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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18
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South A, Lees R, Garrod G, Carson J, Malone D, Hastings I. The role of windows of selection and windows of dominance in the evolution of insecticide resistance in human disease vectors. Evol Appl 2020; 13:738-751. [PMID: 32211064 PMCID: PMC7086049 DOI: 10.1111/eva.12897] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 10/25/2019] [Accepted: 10/28/2019] [Indexed: 01/23/2023] Open
Abstract
Persistent insecticides sprayed onto house walls, and incorporated into insecticide-treated bednets, provide long-acting, cost-effective control of vector-borne diseases such as malaria and leishmaniasis. The high concentrations that occur immediately postdeployment may kill both resistant and susceptible insects. However, insecticide concentration, and therefore killing ability, declines in the months after deployment. As concentrations decline, resistant insects start to survive, while susceptible insects are still killed. The period of time after deployment, within which the mortality of resistant individuals is lower than that of susceptible ones, has been termed the "window of selection" in other contexts. It is recognized as driving resistance in bacteria and malaria parasites, both of which are predominantly haploid. We argue that paying more attention to these mortality differences can help understand the evolution of insecticide resistance. Because insects are diploid, resistance encoded by single genes generates heterozygotes. This gives the potential for a narrower "window of dominance," within the window of selection, where heterozygote mortality is lower than that of susceptible homozygotes. We explore the general properties of windows of selection and dominance in driving resistance. We quantify their likely effect using data from new laboratory experiments and published data from the laboratory and field. These windows can persist months or years after insecticide deployments. Differential mortalities of resistant, susceptible and heterozygous genotypes, after public health deployments, constitute a major challenge to controlling resistance. Greater attention to mortality differences by genotype would inform strategies to reduce the evolution of resistance to existing and new insecticides.
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Affiliation(s)
- Andy South
- Liverpool School of Tropical Medicine (LSTM)LiverpoolUK
| | - Rosemary Lees
- Liverpool School of Tropical Medicine (LSTM)LiverpoolUK
| | - Gala Garrod
- Liverpool School of Tropical Medicine (LSTM)LiverpoolUK
| | | | - David Malone
- Innovative Vector Control Consortium (IVCC)LiverpoolUK
- Present address:
Bill & Melinda Gates FoundationLondonUK
| | - Ian Hastings
- Liverpool School of Tropical Medicine (LSTM)LiverpoolUK
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19
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Mulatier M, Pennetier C, Porciani A, Chandre F, Dormont L, Cohuet A. Prior contact with permethrin decreases its irritancy at the following exposure among a pyrethroid-resistant malaria vector Anopheles gambiae. Sci Rep 2019; 9:8177. [PMID: 31160750 PMCID: PMC6546682 DOI: 10.1038/s41598-019-44633-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 05/21/2019] [Indexed: 11/26/2022] Open
Abstract
Insecticide-treated nets (ITNs) remain major components for vector control despite the spread of resistance mechanisms among mosquito populations. Multiple exposures to pyrethroids may induce physiological and behavioral changes in mosquitoes, possibly reducing efficacy of control tools. Despite epidemiological relevance, the effects of multiple exposures to pyrethroids on their efficacy against pyrethroid-resistant mosquitoes has received little interest. In the present study, we assessed the effects of a blood-meal successfully obtained upon a permethrin-treated net on the success at taking a second blood-meal in presence of permethrin in Anopheles gambiae, carrying pyrethroid resistance alleles. We also measured the impact of exposure to permethrin on life-history traits to address the delayed efficacy of ITNs. Our results showed that females that successfully blood-fed upon a permethrin-treated net were no longer inhibited by permethrin at the following exposure. Blood-meal inhibition due to permethrin was not affected by female size nor by exposure of mothers when testing the offspring, allowing to discard the effect of genetic or physiological selection. Besides, in our assays, exposure to permethrin did not affect mosquito fecundity, fertility nor survival. These results give insights to understand the long-term efficacy of ITNs, and allow to reevaluate the criteria used when choosing compounds for fighting malaria mosquitoes.
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Affiliation(s)
- Margaux Mulatier
- MIVEGEC, IRD, CNRS, Univ. Montpellier, Montpellier, France. .,CEFE, Univ Paul Valéry Montpellier 3, CNRS, Univ Montpellier, EPHE, IRD, Montpellier, France.
| | - Cédric Pennetier
- MIVEGEC, IRD, CNRS, Univ. Montpellier, Montpellier, France.,Institut Pierre Richet, Bouaké, Côte d'Ivoire
| | | | | | - Laurent Dormont
- CEFE, Univ Paul Valéry Montpellier 3, CNRS, Univ Montpellier, EPHE, IRD, Montpellier, France
| | - Anna Cohuet
- Institut Pierre Richet, Bouaké, Côte d'Ivoire
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