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Phanhkongsy S, Suwannatrai A, Thinkhamrop K, Somlor S, Sorsavanh T, Tavinyan V, Sentian V, Khamphilavong S, Samountry B, Phanthanawiboon S. Spatial analysis of dengue fever incidence and serotype distribution in Vientiane Capital, Laos: A multi-year study. Acta Trop 2024; 256:107229. [PMID: 38768698 DOI: 10.1016/j.actatropica.2024.107229] [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: 03/05/2024] [Revised: 04/22/2024] [Accepted: 04/24/2024] [Indexed: 05/22/2024]
Abstract
Laos is a hyperendemic country of all 4 dengue serotypes. Various factors contribute to the spread of the disease including viral itself, vectors, and environment. This study aims to analyze dengue data and its incidence in nine districts of Vientiane Capital, Laos spanning from 2019 to 2021 by data collected from Mittaphab Hospital. The Maximum Entropy algorithm (MaxEnt) was applied to assess spatial distribution and identify high-probability locations for dengue occurrence by analyzing crucial environmental and climatic conditions. Dengue cases were more prominent in female (54.88 %) and highest case number was found in worker group (29.02 %) followed by student (28.47 %) and officer (16.92 %). In this study, the age group 21-30 years old had the highest infection rate (42.23 %), followed by 10-20 years old (24.21 %). Most of dengue cases was primary infection (91.61 %). Dengue serotype 2 predominated in 2019 and 2020 and substitute by serotype 1 in 2021. Across the nine districts of Vientiane Capital, the highest incidence of dengue was found in Xaythany district population in 2019, shifting to Chanthabouly district in 2020 and 2021. The MaxEnt revealed potentially most suitable areas for dengue were widely distributed central south part of Vientiane, Laos. Additionally, the best predictive variable for dengue occurrence was normalized difference vegetation index. Understanding of case characteristics and spatial distribution features of dengue will be helpful in effective surveillance and disease control in the future.
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Affiliation(s)
- Somsouk Phanhkongsy
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Apiporn Suwannatrai
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Kavin Thinkhamrop
- Faculty of Public Health, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Somphavanh Somlor
- Arbovirus & Emerging viral disease laboratory, Institute Pasteur du Laos, Samsenthai Rd, Ban Kao-ngot PO Box 3560, Vientiane, Lao People's Democratic Republic
| | - Thepphouthone Sorsavanh
- Department of Planning and Cooperation, Ministry of Health, Fa Ngoum Road, Thatkhao Village, Sisattanak District, Vientiane, Lao People's Democratic Republic
| | - Vanxay Tavinyan
- Microbiology Unit, Department of Medical Sciences, Faculty of Medicine, Ministry of Health, University of Health Sciences, Samsenthai Road, Ban Kao-ngot PO Box 7444 Vientiane, Lao People's Democratic Republic
| | - Virany Sentian
- Microbiology Unit, Department of Medical Sciences, Faculty of Medicine, Ministry of Health, University of Health Sciences, Samsenthai Road, Ban Kao-ngot PO Box 7444 Vientiane, Lao People's Democratic Republic
| | - Soulichanh Khamphilavong
- Microbiology Unit, Department of Medical Sciences, Faculty of Medicine, Ministry of Health, University of Health Sciences, Samsenthai Road, Ban Kao-ngot PO Box 7444 Vientiane, Lao People's Democratic Republic
| | - Bounthome Samountry
- Pathologist, Ministry of Health, University of Health Sciences, Samsenthai Road, Ban Koa-ngot PO Box 7444, Vientiane, Lao People's Democratic Republic
| | - Supranee Phanthanawiboon
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
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Liu K, Fang S, Li Q, Lou Y. Effectiveness evaluation of mosquito suppression strategies on dengue transmission under changing temperature and precipitation. Acta Trop 2024; 253:107159. [PMID: 38412904 DOI: 10.1016/j.actatropica.2024.107159] [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: 10/07/2023] [Revised: 12/08/2023] [Accepted: 02/23/2024] [Indexed: 02/29/2024]
Abstract
Widespread resurgence of dengue outbreaks has seriously threatened the global health. Due to lack of treatments and vaccines, one key strategy in dengue control is to reduce the vector population size. As an environment-friendly mosquito control approach, releasing male mosquitoes transinfected with specific Wolbachia strain into the field to suppress the wild mosquito population size has become wildly accepted. The current study evaluates the effectiveness of this suppression strategy on dengue control under changing temperature and precipitation profiles. We formulate a mathematical model which includes larval intra-specific competition, the maturation period for mosquitoes, the extrinsic incubation period (EIP) and intrinsic incubation period (IIP). The persistence of mosquitoes and disease is discussed in terms of two basic reproduction numbers (RM and R0) and the release ratio pw. Further numerical simulations are carried out to not only validate theoretical results, but also provide interesting quantitative observations. Sensitivity analysis on the reproduction numbers, peak size, peak time and the final epidemic size is performed with respect to model parameters, which highlights effective control measures against dengue transmission. Moreover, by assuming temperature and precipitation dependent mosquito-related parameters, the model can be used to project the effectiveness of releasing Wolbachia-carrying males under climatic variations. It is shown that the effectiveness of various control strategies is highly dependent on the changing temperature and precipitation profiles. In particular, the model projects that it is most challenging to control the disease at the favorable temperature (around 27∼30∘C) and precipitation (5∼8mm/day) range, during which the basic reproduction number R0 is very high and more Wolbachia-infected males should be released.
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Affiliation(s)
- Kaihui Liu
- School of Mathematical Sciences, Jiangsu University, Zhenjiang, Jiangsu, 212013, China
| | - Shuanghui Fang
- School of Mathematical Sciences, Jiangsu University, Zhenjiang, Jiangsu, 212013, China
| | - Qiong Li
- Guangdong Provincial Key Laboratory of Interdisciplinary Research and Application for Data Science, BNU-HKBU United International College, Zhuhai 519087, China
| | - Yijun Lou
- Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong SAR, China.
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Radwan IT, Khater HF, Mohammed SH, Khalil A, Farghali MA, Mahmoud MG, Selim A, Manaa EA, Bagato N, Baz MM. Synthesis of eco-friendly layered double hydroxide and nanoemulsion for jasmine and peppermint oils and their larvicidal activities against Culex pipiens Linnaeus. Sci Rep 2024; 14:6884. [PMID: 38519561 PMCID: PMC10959945 DOI: 10.1038/s41598-024-56802-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 03/11/2024] [Indexed: 03/25/2024] Open
Abstract
Mosquito-borne diseases represent a growing health challenge over time. Numerous potential phytochemicals are target-specific, biodegradable, and eco-friendly. The larvicidal activity of essential oils, a jasmine blend consisting of Jasmine oil and Azores jasmine (AJ) (Jasminum sambac and Jasminum azoricum) and peppermint (PP) Mentha arvensis and their nanoformulations against 2nd and 4th instar larvae of Culex pipiens, was evaluated after subjecting to different concentrations (62.5, 125, 250, 500, 1000, and 2000 ppm). Two forms of phase-different nanodelivery systems of layered double hydroxide LDH and oil/water nanoemulsions were formulated. The synthesized nanoemulsions showed particle sizes of 199 and 333 nm for AJ-NE and PP-NE, with a polydispersity index of 0.249 and 0.198, respectively. Chemical and physiochemical analysis of TEM, SEM, XRD, zeta potential, drug loading capacity, and drug release measurements were done to confirm the synthesis and loading efficiencies of essential oils' active ingredients. At high concentrations of AJ and PP nanoemulsions (2000 ppm), O/W nanoemulsions showed higher larval mortality than both LDH conjugates and crude oils. The mortality rate reached 100% for 2nd and 4th instar larvae. The relative toxicities revealed that PP nanoemulsion (MA-NE) was the most effective larvicide, followed by AJ nanoemulsion (AJ-NE). There was a significant increase in defensive enzymes, phenoloxidase, and α and β-esterase enzymes in the treated groups. After treatment of L4 with AJ, AJ-NE, PP, and PP-NE, the levels of phenoloxidase were 545.67, 731.00, 700.00, and 799.67 u/mg, respectively, compared with control 669.67 u/mg. The activity levels of α-esterase were 9.71, 10.32, 8.91, and 10.55 mg α-naphthol/min/mg protein, respectively. It could be concluded that the AJ-NE and PP-NE nanoformulations have promising larvicidal activity and could act as safe and effective alternatives to chemical insecticides.
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Affiliation(s)
- Ibrahim Taha Radwan
- Supplementary General Sciences Department, Faculty of Oral and Dental Medicine, Future University in Egypt, Cairo, 11835, Egypt.
| | - Hanem F Khater
- Department of Parasitology, Faculty of Veterinary Medicine, Benha University, Toukh, 13736, Egypt
| | - Shaimaa H Mohammed
- Zoology and Entomology Department, Faculty of Science, Al-Azhar, University (Girls Branch), Cairo, Egypt
| | - Abdelwahab Khalil
- Entomology Division, Zoology Department, Faculty of Science, Beni-Suef University, Beni -Suef, 62521, Egypt
| | - Mohamed A Farghali
- Nanotechnology and Advanced Materials Central Lab (NAMCL), Regional Center for Food & Feed (RCFF), Agricultural Research Center (ARC), Giza, Egypt
| | - Mohammed G Mahmoud
- Plant Protection Department, Faculty of Agriculture, Zagazig University, Zagazig, Egypt
| | - Abdelfattah Selim
- Department of Animal Medicine (Infectious Diseases), Faculty of Veterinary Medicine, Benha University, Toukh, 13736, Egypt
| | - Eman A Manaa
- Animal and Poultry Production, Department of Animal Wealth Development, Faculty of Veterinary Medicine, Benha University, Toukh, 13736, Egypt
| | - Noha Bagato
- Egyptian Petroleum Research Institute (EPRI), PO Box 11727, Nasr City, Cairo, Egypt
| | - Mohamed M Baz
- Departments of Entomology, Faculty of Science, Benha University, Benha, 13518, Egypt.
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Erriah B, Shtukenberg AG, Aronin R, McCarthy D, Brázda P, Ward MD, Kahr B. ROY Crystallization on Poly(ethylene) Fibers, a Model for Bed Net Crystallography. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2024; 36:2432-2440. [PMID: 38495899 PMCID: PMC10938503 DOI: 10.1021/acs.chemmater.3c03188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/13/2024] [Accepted: 02/14/2024] [Indexed: 03/19/2024]
Abstract
Many long-lasting insecticidal bed nets for protection against disease vectors consist of poly(ethylene) fibers in which insecticide is incorporated during manufacture. Insecticide molecules diffuse from within the supersaturated polymers to surfaces where they become bioavailable to insects and often crystallize, a process known as blooming. Recent studies revealed that contact insecticides can be highly polymorphic. Moreover, insecticidal activity is polymorph-dependent, with forms having a higher crystal free energy yielding faster insect knockdown and mortality. Consequently, the crystallographic characterization of insecticide crystals that form on fibers is critical to understanding net function and improving net performance. Structural characterization of insecticide crystals on bed net fiber surfaces, let alone their polymorphs, has been elusive owing to the minute size of the crystals, however. Using the highly polymorphous compound ROY (5-methyl-2-[(2-nitrophenyl)-amino]thiophene-3-carbonitrile) as a proxy for insecticide crystallization, we investigated blooming and crystal formation on the surface of extruded poly(ethylene) fibers containing ROY. The blooming rates, tracked from the time of extrusion, were determined by UV-vis spectroscopy after successive washes. Six crystalline polymorphs (of the 13 known) were observed on poly(ethylene) fiber surfaces, and they were identified and characterized by Raman microscopy, scanning electron microscopy, and 3D electron diffraction. These observations reveal that the crystallization and phase behavior of polymorphs forming on poly(ethylene) fibers is complex and dynamic. The characterization of blooming and microcrystals underscores the importance of bed net crystallography for the optimization of bed net performance.
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Affiliation(s)
- Bryan Erriah
- Department
of Chemistry and Molecular Design Institute, New York University, New York, 29 Washington Place, New York City, New York 10003, United States
| | - Alexander G. Shtukenberg
- Department
of Chemistry and Molecular Design Institute, New York University, New York, 29 Washington Place, New York City, New York 10003, United States
| | - Reese Aronin
- Department
of Chemistry and Molecular Design Institute, New York University, New York, 29 Washington Place, New York City, New York 10003, United States
| | - Derik McCarthy
- Department
of Chemistry and Molecular Design Institute, New York University, New York, 29 Washington Place, New York City, New York 10003, United States
| | - Petr Brázda
- Department
of Structure Analysis, Institute of Physics, Czech Academy of Sciences, Na Slovance 2/1999, Prague 8 18221, Czech Republic
| | - Michael D. Ward
- Department
of Chemistry and Molecular Design Institute, New York University, New York, 29 Washington Place, New York City, New York 10003, United States
| | - Bart Kahr
- Department
of Chemistry and Molecular Design Institute, New York University, New York, 29 Washington Place, New York City, New York 10003, United States
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Zhang R, Liu W, Zhang Z. miR-306-5p is involved in chitin metabolism in Aedes albopictus pupae via linc8338-miR-306-5p-XM_019678125.2 axis. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2024; 200:105811. [PMID: 38582583 DOI: 10.1016/j.pestbp.2024.105811] [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: 09/13/2023] [Revised: 01/31/2024] [Accepted: 02/02/2024] [Indexed: 04/08/2024]
Abstract
Aedes albopictus can transmit several lethal arboviruses. This mosquito has become a sever public health threat due to its rapidly changing global distribution. Chitin, which is the major component of the cuticle and peritrophic membrane (PM), is crucial for the growth and development of insect. microRNAs (miRNAs) play important roles in the posttranscriptional level regulation of gene expression, thereby influencing many biological processes in insects. In this study, an attempt was made to evaluate the role of miR-306-5p in regulating chitin metabolism in Ae. albopictus pupae. Overexpression of miR-306-5p resulted in a significantly reduced survival rate in pupae and an increased malformation rate in adults. Both in vivo and in vitro evidence confirmed the presence of the competing endogenous RNA (ceRNA) regulatory axis (linc8338-miR-306-5p-XM_019678125.2). RNAi of linc8338 and XM_019678125.2 had effects on pupae similar to those of miR-306-5p. The highest expression level of miR-306-5p was found in the midgut, and alteration in the expression of miR-306-5p, XM_019678125.2 and linc8338 induced increased transcript levels of chitin synthase 2 (AaCHS2) and decreased chitinase 10 (AaCht10); as well as increased thickness of the midgut and enlarged midgut epithelial cells. The results of this study highlight the potential of miR-306-5p as a prospective target in mosquito control and confirm that the ceRNA mechanism is involved in chitin metabolism. These findings will provide a basis for further studies to uncover the molecular mechanisms through which ncRNAs regulate chitin metabolism.
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Affiliation(s)
- Ruiling Zhang
- School of Clinical and Basic Medical Science, Shandong First Medical University (Shandong Academy of Medical Sciences), Jinan 250117, China; School of Laboratory Animal & Shandong Laboratory Animal Center, Shandong First Medical University (Shandong Academy of Medical Sciences), Jinan 250117, China.
| | - Wenjuan Liu
- School of Clinical and Basic Medical Science, Shandong First Medical University (Shandong Academy of Medical Sciences), Jinan 250117, China
| | - Zhong Zhang
- School of Clinical and Basic Medical Science, Shandong First Medical University (Shandong Academy of Medical Sciences), Jinan 250117, China.
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Lamsal M, Luker HA, Pinch M, Hansen IA. RNAi-Mediated Knockdown of Acidic Ribosomal Stalk Protein P1 Arrests Egg Development in Adult Female Yellow Fever Mosquitoes, Aedes aegypti. INSECTS 2024; 15:84. [PMID: 38392504 PMCID: PMC10889338 DOI: 10.3390/insects15020084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/10/2024] [Accepted: 01/20/2024] [Indexed: 02/24/2024]
Abstract
After taking a blood meal, the fat body of the adult female yellow fever mosquito, Aedes aegypti, switches from a previtellogenic state of arrest to an active state of synthesizing large quantities of yolk protein precursors (YPPs) that are crucial for egg development. The synthesis of YPPs is regulated at both the transcriptional and translational levels. Previously, we identified the cytoplasmic protein general control nonderepressible 1 (GCN1) as a part of the translational regulatory pathway for YPP synthesis. In the current study, we used the C-terminal end of GCN1 to screen for protein-protein interactions and identified 60S acidic ribosomal protein P1 (P1). An expression analysis and RNAi-mediated knockdown of P1 was performed to further investigate the role of P1 in mosquito reproduction. We showed that in unfed (absence of a blood meal) adult A. aegypti mosquitoes, P1 was expressed ubiquitously in the mosquito organs and tissues tested. We also showed that the RNAi-mediated knockdown of P1 in unfed adult female mosquitoes resulted in a strong, transient knockdown with observable phenotypic changes in ovary length and egg deposition. Our results suggest that 60S acidic ribosomal protein P1 is necessary for mosquito reproduction and is a promising target for mosquito population control.
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Affiliation(s)
- Mahesh Lamsal
- Molecular Vector Physiology Laboratory, Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
| | - Hailey A Luker
- Molecular Vector Physiology Laboratory, Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
| | - Matthew Pinch
- Department of Biology, University of Texas El Paso, El Paso, TX 79968, USA
| | - Immo A Hansen
- Molecular Vector Physiology Laboratory, Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
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Hadebe MT, Malgwi SA, Okpeku M. Revolutionizing Malaria Vector Control: The Importance of Accurate Species Identification through Enhanced Molecular Capacity. Microorganisms 2023; 12:82. [PMID: 38257909 PMCID: PMC10818655 DOI: 10.3390/microorganisms12010082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 12/08/2023] [Accepted: 12/20/2023] [Indexed: 01/24/2024] Open
Abstract
Many factors, such as the resistance to pesticides and a lack of knowledge of the morphology and molecular structure of malaria vectors, have made it more challenging to eradicate malaria in numerous malaria-endemic areas of the globe. The primary goal of this review is to discuss malaria vector control methods and the significance of identifying species in vector control initiatives. This was accomplished by reviewing methods of molecular identification of malaria vectors and genetic marker classification in relation to their use for species identification. Due to its specificity and consistency, molecular identification is preferred over morphological identification of malaria vectors. Enhanced molecular capacity for species identification will improve mosquito characterization, leading to accurate control strategies/treatment targeting specific mosquito species, and thus will contribute to malaria eradication. It is crucial for disease epidemiology and surveillance to accurately identify the Plasmodium spp. that are causing malaria in patients. The capacity for disease surveillance will be significantly increased by the development of more accurate, precise, automated, and high-throughput diagnostic techniques. In conclusion, although morphological identification is quick and achievable at a reduced cost, molecular identification is preferred for specificity and sensitivity. To achieve the targeted malaria elimination goal, proper identification of vectors using accurate techniques for effective control measures should be prioritized.
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Affiliation(s)
| | | | - Moses Okpeku
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville, Durban 4000, South Africa
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Wang H, Yang X, Liu J, Xu J, Zhang R, Zheng J, Shen B, Sun Y, Zhou D. Adverse effects of knocking down chitin synthase A on female reproduction in Culex pipiens pallens (Diptera: Culicidae). PEST MANAGEMENT SCIENCE 2023; 79:4463-4473. [PMID: 37409377 DOI: 10.1002/ps.7648] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 04/29/2023] [Accepted: 07/06/2023] [Indexed: 07/07/2023]
Abstract
BACKGROUND Current mosquito-borne disease vector control strategies, largely based on chemical insecticides, are seriously threatened by increasing resistance worldwide. There is also growing concerned about the adverse effects of insecticides on nontarget organisms and the environment, therefore effective and ecologically friendly alternative approaches are urgently needed. Targeting critical steps of reproduction is considered a potential way to control mosquito populations. Herein, we focused on the roles of chitin synthase A (encoded by chsa) in the reproduction of female mosquitoes. RESULTS The injection of small interfering RNA targeting Cpchsa in female Culex pipiens pallens (Diptera: Culicidae) had antireproductive effects, including decreased follicle numbers, egg-laying, and hatching rate. Scanning electron microscopy observations showed that Cpchsa silencing caused a defective egg envelope, including absence of the vitelline membrane and cracked chorion layers, which resulted in abnormal permeability. Widely distributed nurse cell apoptosis and follicular epithelial cell autophagy were observed in Cpchsa-silenced ovaries during the vitellogenesis phase. Consistent with the detective egg envelope formation during oogenesis, the exochorionic eggshell structures were also affected in eggs deposited by Cpchsa-silenced mosquitoes. CONCLUSION This study provided fundamental evidence for the role of chitin synthase A in the female reproductive process of mosquitoes and might result in a novel alternative strategy for mosquito control. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Huan Wang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, China
| | - Xiaoshan Yang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, China
| | - Jin Liu
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, China
| | - Jingwei Xu
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, China
| | - Ruimin Zhang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, China
| | - Junnan Zheng
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, China
| | - Bo Shen
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, China
| | - Yan Sun
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, China
| | - Dan Zhou
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, China
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Lord JS, Bonsall MB. Mechanistic modelling of within-mosquito viral dynamics: Insights into infection and dissemination patterns. PLoS Comput Biol 2023; 19:e1011520. [PMID: 37812643 PMCID: PMC10586656 DOI: 10.1371/journal.pcbi.1011520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 10/19/2023] [Accepted: 09/15/2023] [Indexed: 10/11/2023] Open
Abstract
Vector or host competence can be defined as the ability of an individual to become infected and subsequently transmit a pathogen. Assays to measure competence play a key part in the assessment of the factors affecting mosquito-borne virus transmission and of potential pathogen-blocking control tools for these viruses. For mosquitoes, competence for arboviruses can be measured experimentally and results are usually analysed using standard statistical approaches. Here we develop a mechanistic approach to studying within-mosquito virus dynamics that occur during vector competence experiments. We begin by developing a deterministic model of virus replication in the mosquito midgut and subsequent escape and replication in the hemocoel. We then extend this to a stochastic model to capture the between-individual variation observed in vector competence experiments. We show that the dose-response of the probability of mosquito midgut infection and variation in the dissemination rate can be explained by stochastic processes generated from a small founding population of virions, caused by a relatively low rate of virion infection of susceptible cells. We also show that comparing treatments or species in competence experiments by fitting mechanistic models could provide further insight into potential differences. Generally, our work adds to the growing body of literature emphasizing the importance of intrinsic stochasticity in biological systems.
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Affiliation(s)
- Jennifer S. Lord
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Moturi AK, Jalang'o R, Cherono A, Muchiri SK, Snow RW, Okiro EA. Malaria vaccine coverage estimation using age-eligible populations and service user denominators in Kenya. Malar J 2023; 22:287. [PMID: 37759277 PMCID: PMC10523632 DOI: 10.1186/s12936-023-04721-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 09/21/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND The World Health Organization approved the RTS,S/AS01 malaria vaccine for wider rollout, and Kenya participated in a phased pilot implementation from 2019 to understand its impact under routine conditions. Vaccine delivery requires coverage measures at national and sub-national levels to evaluate progress over time. This study aimed to estimate the coverage of the RTS,S/AS01 vaccine during the first 36 months of the Kenyan pilot implementation. METHODS Monthly dose-specific immunization data for 23 sub-counties were obtained from routine health information systems at the facility level for 2019-2022. Coverage of each RTS,S/AS01 dose was determined using reported doses as a numerator and service-based (Penta 1 and Measles) or population (projected infant populations from WorldPop) as denominators. Descriptive statistics of vaccine delivery, dropout rates and coverage estimates were computed across the 36-month implementation period. RESULTS Over 36 months, 818,648 RTSS/AS01 doses were administered. Facilities managed by the Ministry of Health and faith-based organizations accounted for over 88% of all vaccines delivered. Overall, service-based malaria vaccine coverage was 96%, 87%, 78%, and 39% for doses 1-4 respectively. Using a population-derived denominator for age-eligible children, vaccine coverage was 78%, 68%, 57%, and 24% for doses 1-4, respectively. Of the children that received measles dose 1 vaccines delivered at 9 months (coverage: 95%), 82% received RTSS/AS01 dose 3, only 66% of children who received measles dose 2 at 18 months (coverage: 59%) also received dose 4. CONCLUSION The implementation programme successfully maintained high levels of coverage for the first three doses of RTSS/AS01 among children defined as EPI service users up to 9 months of age but had much lower coverage within the community with up to 1 in 5 children not receiving the vaccine. Consistent with vaccines delivered over the age of 1 year, coverage of the fourth malaria dose was low. Vaccine uptake, service access and dropout rates for malaria vaccines require constant monitoring and intervention to ensure maximum protection is conferred.
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Affiliation(s)
- Angela K Moturi
- Population & Health Impact Surveillance Group, KEMRI-Wellcome Trust Research Programme, Nairobi, Kenya.
| | - Rose Jalang'o
- National Vaccines & Immunization Programme, Ministry of Health, Nairobi, Kenya
| | - Anitah Cherono
- Population & Health Impact Surveillance Group, KEMRI-Wellcome Trust Research Programme, Nairobi, Kenya
| | - Samuel K Muchiri
- Population & Health Impact Surveillance Group, KEMRI-Wellcome Trust Research Programme, Nairobi, Kenya
| | - Robert W Snow
- Population & Health Impact Surveillance Group, KEMRI-Wellcome Trust Research Programme, Nairobi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Emelda A Okiro
- Population & Health Impact Surveillance Group, KEMRI-Wellcome Trust Research Programme, Nairobi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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Harikrishnan S, Sudarshan S, Sivasubramani K, Nandini MS, Narenkumar J, Ramachandran V, Almutairi BO, Arunkumar P, Rajasekar A, Jayalakshmi S. Larvicidal and anti-termite activities of microbial biosurfactant produced by Enterobacter cloacae SJ2 isolated from marine sponge Clathria sp. Sci Rep 2023; 13:15153. [PMID: 37704703 PMCID: PMC10499797 DOI: 10.1038/s41598-023-42475-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 09/11/2023] [Indexed: 09/15/2023] Open
Abstract
The widespread use of synthetic pesticides has resulted in a number of issues, including a rise in insecticide-resistant organisms, environmental degradation, and a hazard to human health. As a result, new microbial derived insecticides that are safe for human health and the environment are urgently needed. In this study, rhamnolipid biosurfactants produced from Enterobacter cloacae SJ2 was used to evaluate the toxicity towards mosquito larvae (Culex quinquefasciatus) and termites (Odontotermes obesus). Results showed dose dependent mortality rate was observed between the treatments. The 48 h LC50 (median lethal concentration) values of the biosurfactant were determined for termite and mosquito larvae following the non-linear regression curve fit method. Results showed larvicidal activity and anti-termite activity of biosurfactants with 48 h LC50 value (95% confidence interval) of 26.49 mg/L (25.40 to 27.57) and 33.43 mg/L (31.09 to 35.68), respectively. According to a histopathological investigation, the biosurfactant treatment caused substantial tissue damage in cellular organelles of larvae and termites. The findings of this study suggest that the microbial biosurfactant produced by E. cloacae SJ2 is an excellent and potentially effective agent for controlling Cx. quinquefasciatus and O. obesus.
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Affiliation(s)
- Sekar Harikrishnan
- Centre of Advanced Study in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai, Tamil Nadu, 608502, India.
| | - Shanmugam Sudarshan
- Department of Aquatic Environment Management, TNJFU- Dr. M.G.R Fisheries College and Research Institute, Thalainayeru, Tamil Nadu, 614712, India
| | - Kandasamy Sivasubramani
- Department of Microbiology, Faculty of Science, Annamalai University, Annamalai Nagar, Chidambaram, Tamil Nadu, India
| | - M S Nandini
- Department of Microbiology, Sree Balaji Medical College and Hospital, Chennai, Tamil Nadu, India
| | - Jayaraman Narenkumar
- Department of Environmental & Water Resources Engineering, School of Civil Engineering (SCE), Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India.
| | - Vasudevan Ramachandran
- Department of Medical Sciences, University College of MAIWP International, Taman Batu Muda, 68100, Batu Caves, Kuala Lumpur, Malaysia
- Department of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, India
| | - Bader O Almutairi
- Department of Zoology, College of Science, King Saud University, 11451, Riyadh, Saudi Arabia
| | - Paulraj Arunkumar
- School of Chemical Engineering, Chonnam National University, Gwangju, South Korea
| | - Aruliah Rajasekar
- Environmental Molecular Microbiology Research Laboratory, Department of Biotechnology, Thiruvalluvar University, Serkkadu, Vellore, Tamil Nadu, 632115, India
| | - Singaram Jayalakshmi
- Centre of Advanced Study in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai, Tamil Nadu, 608502, India
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12
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Bozorg-Omid F, Kafash A, Jafari R, Akhavan AA, Rahimi M, Rahimi Foroushani A, Youssefi F, Shirzadi MR, Ostadtaghizadeh A, Hanafi-Bojd AA. Predicting current and future high-risk areas for vectors and reservoirs of cutaneous leishmaniasis in Iran. Sci Rep 2023; 13:11546. [PMID: 37460690 PMCID: PMC10352301 DOI: 10.1038/s41598-023-38515-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 07/10/2023] [Indexed: 07/20/2023] Open
Abstract
Climate change will affect the distribution of species in the future. To determine the vulnerable areas relating to CL in Iran, we applied two models, MaxEnt and RF, for the projection of the future distribution of the main vectors and reservoirs of CL. The results of the models were compared in terms of performance, species distribution maps, and the gain, loss, and stable areas. The models provided a reasonable estimate of species distribution. The results showed that the Northern and Southern counties of Iran, which currently do not have a high incidence of CL may witness new foci in the future. The Western, and Southwestern regions of the Country, which currently have high habitat suitability for the presence of some vectors and reservoirs, will probably significantly decrease in the future. Furthermore, the most stable areas are for T. indica and M. hurrianae in the future. So that, this species may remain a major reservoir in areas that are present under current conditions. With more local studies in the field of identifying vulnerable areas to CL, it can be suggested that the national CL control guidelines should be revised to include a section as a climate change adaptation plan.
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Affiliation(s)
- Faramarz Bozorg-Omid
- Department of Vector Biology and Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Anooshe Kafash
- Zoonoses Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Jafari
- School of Public Health, Esfahan Health Research Station, Tehran University of Medical Sciences, Tehran, Iran
| | - Amir Ahmad Akhavan
- Department of Vector Biology and Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Rahimi
- Department of Combat Desertification, Faculty of Desert Studies, Semnan University, Semnan, Iran
| | - Abbas Rahimi Foroushani
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Fahimeh Youssefi
- Department of Photogrammetry and Remote Sensing, Faculty of Geodesy and Geomatics Engineering, K. N. Toosi University of Technology, Tehran, Iran
| | - Mohammad Reza Shirzadi
- Center for Research of Endemic Parasites of Iran, Tehran University of Medical Sciences, Tehran, Iran
- Center for Communicable Diseases Control, Ministry of Health and Medical Education, Tehran, Iran
| | - Abbas Ostadtaghizadeh
- Department of Health in Emergencies and Disasters, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
| | - Ahmad Ali Hanafi-Bojd
- Department of Vector Biology and Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
- Zoonoses Research Center, Tehran University of Medical Sciences, Tehran, Iran.
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13
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Lim H, Lee SY, Ho LY, Sit NW. Mosquito Larvicidal Activity and Cytotoxicity of the Extracts of Aromatic Plants from Malaysia. INSECTS 2023; 14:512. [PMID: 37367328 DOI: 10.3390/insects14060512] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/23/2023] [Accepted: 05/27/2023] [Indexed: 06/28/2023]
Abstract
Despite ongoing control efforts, the mosquito population and diseases vectored by them continue to thrive worldwide, causing major health concerns. There has been growing interest in the use of botanicals as alternatives to insecticides due to their widespread insecticidal properties, biodegradability, and adaptability to ecological conditions. In this study, we investigated the larvicidal activity and cytotoxicity effects of solvent extracts from three aromatic plants-Curcuma longa (turmeric), Ocimum americanum (hoary basil), and Petroselinum crispum (parsley)-against Aedes albopictus. Subsequently, we examined the phytochemical composition of the extracts through gas chromatography-mass spectrometry (GC-MS) analysis. Results revealed that the hexane extracts of O. americanum and P. crispum exhibited the greatest larvicidal activity with the lowest median lethal concentration (LC50) values (<30 µg/mL) at 24 h post-treatment, with the former found to be significantly less toxic towards African monkey kidney (Vero) cells. The GC-MS analysis of the said extract indicated the presence of different classes of metabolites, including phenylpropanoids, very long-chain alkanes, fatty acids and their derivatives, and terpenes, with the most abundant component being methyl eugenol (55.28%), most of which, have been documented for their larvicidal activities. These findings provide valuable insights into the potential use and development of bioinsecticides, particularly from O. americanum.
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Affiliation(s)
- Huimei Lim
- Department of Allied Health Sciences, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, Kampar 31900, Malaysia
| | - Sook Yee Lee
- Department of Allied Health Sciences, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, Kampar 31900, Malaysia
| | - Lai Yee Ho
- Department of Allied Health Sciences, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, Kampar 31900, Malaysia
| | - Nam Weng Sit
- Department of Allied Health Sciences, Faculty of Science, Universiti Tunku Abdul Rahman, Bandar Barat, Kampar 31900, Malaysia
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14
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Deng W, Li M, Liu S, Logan JG, Mo J. Repellent Screening of Selected Plant Essential Oils Against Dengue Fever Mosquitoes Using Behavior Bioassays. NEOTROPICAL ENTOMOLOGY 2023; 52:521-529. [PMID: 36928838 PMCID: PMC10181966 DOI: 10.1007/s13744-023-01039-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 03/07/2023] [Indexed: 05/13/2023]
Abstract
Among the efforts to reduce mosquito-transmitted diseases, such as malaria and dengue fever, essential oils (EOs) have become increasingly popular as natural replacements for the repellant DEET. In this study, seven commercially available plant EOs against Aedes species mosquitoes were evaluated for their complete protection time (CPT, min) in vivo using human-hand in cage tests (GB2009/China and WHO2009). Among the EOs with the highest efficacy in repelling mosquitoes, Aedes albopictus (Skuse) were clove bud oil and patchouli oil. Both were further assessed according to the in vivo method recommended by the WHO, to determine their minimum effective dose and CPT. A comparison of the ED50 values (dose yielding a 50% repellent response) of these two EOs against Aedes aegypti(L.) showed that the ED50 (2.496 µg/cm2) of patchouli oil was 1248 times higher than that of clove bud oil (0.002 µg/cm2), thus demonstrating them greater efficacy of the latter in repelling Ae. aegypti mosquitoes. For the 2 EOs, eugenol was the major component with higher than 80% in relative amount of the clove bud oil. The patchouli oil had more than 30% of character chemical patchouli alcohol along with α-bulnesene (10.962%), α-guaiene (9.227%), and seychellene (7.566%). Clove bud oil was found to confer longer complete protection than patchouli oil against a common species of mosquito. These results suggest use of EOs as safe, highly potent repellents for use in daily life and against mosquito-transmitted diseases, such as malaria and dengue fever.
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Affiliation(s)
- Wan Deng
- State Key Lab of Utilization of Woody Oil Resource, Research Institute of Forest and Grass Protection, Hunan Academy of Forestry, Changsha, China
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang Univ, Hangzhou, China
- Dept of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Mi Li
- State Key Lab of Utilization of Woody Oil Resource, Research Institute of Forest and Grass Protection, Hunan Academy of Forestry, Changsha, China
| | - Sisi Liu
- State Key Lab of Utilization of Woody Oil Resource, Research Institute of Forest and Grass Protection, Hunan Academy of Forestry, Changsha, China
| | - James G Logan
- Dept of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
- Arctech Innovation Ltd, the Cube, Dagenham, UK
| | - Jianchu Mo
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang Univ, Hangzhou, China.
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15
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Wang LM, Li N, Zhang M, Tang Q, Lu HZ, Zhou QY, Niu JX, Xiao L, Peng ZY, Zhang C, Liu M, Wang DQ, Deng SQ. The sex pheromone heptacosane enhances the mating competitiveness of sterile Aedes aegypti males. Parasit Vectors 2023; 16:102. [PMID: 36922826 PMCID: PMC10015913 DOI: 10.1186/s13071-023-05711-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/22/2023] [Indexed: 03/17/2023] Open
Abstract
BACKGROUND Aedes aegypti is a vector that transmits various viral diseases, including dengue and Zika. The radiation-based sterile insect technique (SIT) has a limited effect on mosquito control because of the difficulty in irradiating males without reducing their mating competitiveness. In this study, the insect sex pheromone heptacosane was applied to Ae. aegypti males to investigate whether it could enhance the mating competitiveness of irradiated males. METHODS Heptacosane was smeared on the abdomens of Ae. aegypti males that were allowed to mate with untreated virgin females. The insemination rate was used to assess the attractiveness of heptacosane-treated males to females. The pupae were irradiated with different doses of X-rays and γ-rays, and the emergence, survival time, egg number, and hatch rate were detected to find the optimal dose of X-ray and γ-ray radiation. The males irradiated at the optimal dose were smeared with heptacosane, released in different ratios with untreated males, and mated with females. The effect of heptacosane on the mating competitiveness of irradiated mosquitoes was then evaluated by the hatch rate, induced sterility, and mating competitiveness index. RESULTS Applying heptacosane to Ae. aegypti males significantly increased the insemination rate of females by 20%. Pupal radiation did not affect egg number but significantly reduced survival time and hatch rate. The emergence of the pupae was not affected by X-ray radiation but was affected by γ-ray radiation. Pupae exposed to 60 Gy X-rays and 40 Gy γ-rays were selected for subsequent experiments. After 60 Gy X-ray irradiation or 40 Gy γ-ray irradiation, the average hatch rate was less than 0.1%, and the average survival time was more than 15 days. Moreover, at the same release ratio, the hatch rate of the irradiated group perfumed with heptacosane was lower than that of the group without heptacosane. Conversely, the male sterility and male mating competitiveness index were significantly increased due to the use of heptacosane. CONCLUSIONS The sex pheromone heptacosane enhanced the interaction between Ae. aegypti males and females. Perfuming males irradiated by X-rays or γ-rays with heptacosane led to a significant increase in mating competitiveness. This study provided a new idea for improving the application effect of SIT.
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Affiliation(s)
- Lin-Min Wang
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, the Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Ni Li
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, the Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Mao Zhang
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, the Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Qi Tang
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, the Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Hong-Zheng Lu
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, the Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Qing-Ya Zhou
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, the Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Jia-Xuan Niu
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, the Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Liang Xiao
- Department of Radiotherapy, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Zhe-Yu Peng
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, the Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Chao Zhang
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, the Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Miao Liu
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, the Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China.
| | - Duo-Quan Wang
- Chinese Center for Disease Control and Prevention, National Institute of Parasitic Diseases, Shanghai, China.
| | - Sheng-Qun Deng
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, the Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China.
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16
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Rodríguez-González S, Portela R, Córdoba-Aguilar A. Research trends in mosquito studies in urban areas. Acta Trop 2023; 241:106888. [PMID: 36889424 DOI: 10.1016/j.actatropica.2023.106888] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 02/27/2023] [Accepted: 03/04/2023] [Indexed: 03/08/2023]
Abstract
Urbanization is causing a significant impact on biodiversity and human health. The increase in vector-borne diseases in recent decades is linked to changes in the environment due to urbanization. We have reviewed published information on urban mosquitoes from around the globe to examine major study trends in terms of urbanization, and the type of arboviruses they vector. Our review showed a surge in research on urban mosquitoes in the past 15 years, with the majority of studies conducted in the Americas and focusing on Aedes aegypti and Ae. albopictus. However, the findings also highlight a lack of basic monitoring data on mosquito diversity and vector-borne diseases in many countries, which poses a challenge for disease control.
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Affiliation(s)
- Stephany Rodríguez-González
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México; Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510 Coyoacán, Ciudad de México, Mexico
| | - Renato Portela
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510 Coyoacán, Ciudad de México, Mexico
| | - Alex Córdoba-Aguilar
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510 Coyoacán, Ciudad de México, Mexico.
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17
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Seok S, Raz CD, Miller JH, Malcolm AN, Eason MD, Romero-Weaver AL, Giordano BV, Jacobsen CM, Wang X, Akbari OS, Raban R, Mathias DK, Caragata EP, Vorsino AE, Chiu JC, Lee Y. Arboviral disease outbreaks, Aedes mosquitoes, and vector control efforts in the Pacific. FRONTIERS IN TROPICAL DISEASES 2023. [DOI: 10.3389/fitd.2023.1035273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Recurring outbreaks of mosquito-borne diseases, like dengue, in the Pacific region represent a major biosecurity risk to neighboring continents through potential introductions of disease-causing pathogens. Aedes mosquitoes, highly prevalent in this region, are extremely invasive and the predominant vectors of multiple viruses including causing dengue, chikungunya, and Zika. Due to the absence of vaccines for most of these diseases, Aedes control remains a high priority for public health. Currently, international organizations put their efforts into improving mosquito surveillance programs in the Pacific region. Also, a novel biocontrol method using Wolbachia has been tried in the Pacific region to control Aedes mosquito populations. A comprehensive understanding of mosquito biology is needed to assess the risk that mosquitoes might be introduced to neighboring islands in the region and how this might impact arboviral virus transmission. As such, we present a comprehensive review of arboviral disease outbreak records as well as Aedes mosquito biology research findings relevant to the Pacific region collected from both non-scientific and scientific sources.
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Culex Mosquito Piwi4 Is Antiviral against Two Negative-Sense RNA Viruses. Viruses 2022; 14:v14122758. [PMID: 36560761 PMCID: PMC9781653 DOI: 10.3390/v14122758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/06/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022] Open
Abstract
Culex spp. mosquitoes transmit several pathogens concerning public health, including West Nile virus and Saint Louis encephalitis virus. Understanding the antiviral immune system of Culex spp. mosquitoes is important for reducing the transmission of these viruses. Mosquitoes rely on RNA interference (RNAi) to control viral replication. While the siRNA pathway in mosquitoes is heavily studied, less is known about the piRNA pathway. The piRNA pathway in mosquitoes has recently been connected to mosquito antiviral immunity. In Aedes aegypti, Piwi4 has been implicated in antiviral responses. The antiviral role of the piRNA pathway in Culex spp. mosquitoes is understudied compared to Ae. aegypti. Here, we aimed to identify the role of PIWI genes and piRNAs in Culex quinquefasciatus and Culex tarsalis cells during virus infection. We examined the effect of PIWI gene silencing on virus replication of two arboviruses and three insect-specific viruses in Cx. quinquefasciatus derived cells (Hsu) and Cx. tarsalis derived (CT) cells. We show that Piwi4 is antiviral against the La Crosse orthobunyavirus (LACV) in Hsu and CT cells, and the insect-specific rhabdovirus Merida virus (MERDV) in Hsu cells. None of the silenced PIWI genes impacted replication of the two flaviviruses Usutu virus (USUV) and Calbertado virus, or the phasivirus Phasi-Charoen-like virus. We further used small RNA sequencing to determine that LACV-derived piRNAs, but not USUV-derived piRNAs were generated in Hsu cells and that PIWI gene silencing resulted in a small reduction in vpiRNAs. Finally, we determined that LACV-derived DNA was produced in Hsu cells during infection, but whether this viral DNA is required for vpiRNA production remains unclear. Overall, we expanded our knowledge on the piRNA pathway and how it relates to the antiviral response in Culex spp mosquitoes.
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19
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Zhao DZ, Wang XK, Zhao T, Li H, Xing D, Gao HT, Song F, Chen GH, Li CX. A Swin Transformer-based model for mosquito species identification. Sci Rep 2022; 12:18664. [PMID: 36333318 PMCID: PMC9636261 DOI: 10.1038/s41598-022-21017-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 09/21/2022] [Indexed: 11/06/2022] Open
Abstract
Mosquito transmit numbers of parasites and pathogens resulting in fatal diseases. Species identification is a prerequisite for effective mosquito control. Existing morphological and molecular classification methods have evitable disadvantages. Here we introduced Deep learning techniques for mosquito species identification. A balanced, high-definition mosquito dataset with 9900 original images covering 17 species was constructed. After three rounds of screening and adjustment-testing (first round among 3 convolutional neural networks and 3 Transformer models, second round among 3 Swin Transformer variants, and third round between 2 images sizes), we proposed the first Swin Transformer-based mosquito species identification model (Swin MSI) with 99.04% accuracy and 99.16% F1-score. By visualizing the identification process, the morphological keys used in Swin MSI were similar but not the same as those used by humans. Swin MSI realized 100% subspecies-level identification in Culex pipiens Complex and 96.26% accuracy for novel species categorization. It presents a promising approach for mosquito identification and mosquito borne diseases control.
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Affiliation(s)
- De-zhong Zhao
- grid.48166.3d0000 0000 9931 8406College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing, 100029 China ,grid.410740.60000 0004 1803 4911State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071 China
| | - Xin-kai Wang
- grid.410740.60000 0004 1803 4911State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071 China ,grid.22935.3f0000 0004 0530 8290Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, 100193 China
| | - Teng Zhao
- grid.410740.60000 0004 1803 4911State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071 China
| | - Hu Li
- grid.22935.3f0000 0004 0530 8290Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, 100193 China
| | - Dan Xing
- grid.410740.60000 0004 1803 4911State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071 China
| | - He-ting Gao
- grid.410740.60000 0004 1803 4911State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071 China
| | - Fan Song
- grid.22935.3f0000 0004 0530 8290Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, 100193 China
| | - Guo-hua Chen
- grid.48166.3d0000 0000 9931 8406College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing, 100029 China
| | - Chun-xiao Li
- grid.410740.60000 0004 1803 4911State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100071 China
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20
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Genomic Characterization of Twelve Lytic Bacteriophages Infecting Midgut Bacteria of Aedes aegypti. Curr Microbiol 2022; 79:385. [DOI: 10.1007/s00284-022-03092-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 10/15/2022] [Indexed: 11/06/2022]
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21
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Guo Z, Jing W, Liu J, Liu M. The global trends and regional differences in incidence of Zika virus infection and implications for Zika virus infection prevention. PLoS Negl Trop Dis 2022; 16:e0010812. [PMID: 36269778 PMCID: PMC9586358 DOI: 10.1371/journal.pntd.0010812] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 09/14/2022] [Indexed: 11/07/2022] Open
Abstract
Background Zika virus (ZIKV) infection has potential result in severe birth effects. An improved understanding of global trend and regional differences is needed. Methods Annual ZIKV infection episodes and incidence rates were collected from Global Burden of Disease Study 2019. Episodes changes and estimated annual percentage changes (EAPCs) of age-standardized incidence rate (ASR) were calculated. Top passenger airport-pairs were obtained from the International Air Transport Association to understand places susceptible to imported ZIKV cases. Results Globally, the ASR increased by an average of 72.85% (95%CI: 16.47% to 156.53%) per year from 2011 to 2015 and subsequently decreased from 20.25 per 100,000 in 2015 to 3.44 per 100,000 in 2019. Most of ZIKV infections clustered in Latin America. The proportion of episodes in Central and Tropical Latin America decreased in 2019 with sporadic episodes elsewhere. High Socio-Demographic Index (SDI) regions had more episodes in 2019 than in 2015. Additionally, 15–49 years group had the largest proportion of episodes, females had a higher number of episodes, and a higher incidence rate of 70 plus group was observed in males than females. Certain cities in Europe, North America and Latin America/Caribbean had a high population mobility in ZIKV outbreak areas considered a high risk of imported cases. Conclusions ZIKV infection is still a public health threat in Latin America and Caribbean and high SDI regions suffered an increasing trend of ZIKV infection. Interventions such as development of surveillance networks and vector-control should be attached to ZIKV control in these key regions. Reproductive suggestions should be taken to reduce ZIKV-related birth defects for the people of reproductive age who are facing a higher threat of ZIKV infection, especially females. Moreover, surveillance of travellers is needed to reverse the uptrends of travel-related imported ZIKV infection. More studies focusing on ZIKV should be performed to make targeted and effective prevention strategies in the future. Zika virus (ZIKV) infection is a mosquito-borne illness and has potential result in severe birth effects. Currently, ZIKV is still causing an unprecedented ongoing epidemic in Latin America and threatening North America and potentially the rest of the world. This is the first study to assess the global landscape, long-term trends and regional differences in the incidence of ZIKV infection using the data from Global Burden of Disease (GBD) Study 2019, including the description of ZIKV infection episodes by different sex and by different year group, as well as the relationship between international travellers and imported ZIKV cases. Our study can not only serve as complement to previous studies, but also provide a more comprehensive perspective of global ZIKV infection prevention strategies.
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Affiliation(s)
- Zirui Guo
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China
| | - Wenzhan Jing
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China
| | - Jue Liu
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China
| | - Min Liu
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China
- * E-mail:
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22
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Species distribution models applied to mosquitoes: Use, quality assessment, and recommendations for best practice. Ecol Modell 2022. [DOI: 10.1016/j.ecolmodel.2022.110073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Buxton M, Cuthbert RN, Basinyi PL, Dalu T, Wasserman RJ, Nyamukondiwa C. Cattle dung in aquatic habitats alters mosquito predatory biocontrol dynamics. FOOD WEBS 2022. [DOI: 10.1016/j.fooweb.2022.e00241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Forson AO, Hinne IA, Dhikrullahi SB, Sraku IK, Mohammed AR, Attah SK, Afrane YA. The resting behavior of malaria vectors in different ecological zones of Ghana and its implications for vector control. Parasit Vectors 2022; 15:246. [PMID: 35804461 PMCID: PMC9270803 DOI: 10.1186/s13071-022-05355-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 06/10/2022] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND In sub-Saharan Africa there is widespread use of long-lasting insecticidal nets and indoor residual spraying to help control the densities of malaria vectors and decrease the incidence of malaria. This study was carried out to investigate the resting behavior, host preference and infection with Plasmodium falciparum of malaria vectors in Ghana in the context of the increasing insecticide resistance of malaria vectors in sub-Saharan Africa. METHODS Indoor and outdoor resting anopheline mosquitoes were sampled during the dry and rainy seasons in five sites in three ecological zones [Sahel savannah (Kpalsogo, Pagaza, Libga); coastal savannah (Anyakpor); and forest (Konongo)]. Polymerase chain reaction-based molecular diagnostics were used to determine speciation, genotypes for knockdown resistance mutations (L1014S and L1014F) and the G119S ace1 mutation, specific host blood meal origins and sporozoite infection in the field-collected mosquitoes. RESULTS Anopheles gambiae sensu lato (s.l.) predominated (89.95%, n = 1718), followed by Anopheles rufipes (8.48%, n = 162) and Anopheles funestus s.l. (1.57%, n = 30). Sibling species of the Anopheles gambiae s.l. revealed Anopheles coluzzii accounted for 63% (95% confidence interval = 57.10-68.91) and 27% (95% confidence interval = 21.66-32.55) was Anopheles gambiae s. s.. The mean resting density of An. gambiae s.l. was higher outdoors (79.63%; 1368/1718) than indoors (20.37%; 350/1718) (Wilcoxon rank sum test, Z = - 4.815, P < 0.0001). The kdr west L1014F and the ace1 mutation frequencies were higher in indoor resting An. coluzzii and An. gambiae in the Sahel savannah sites than in the forest and coastal savannah sites. Overall, the blood meal analyses revealed that a larger proportion of the malaria vectors preferred feeding on humans (70.2%) than on animals (29.8%) in all of the sites. Sporozoites were only detected in indoor resting An. coluzzii from the Sahel savannah (5.0%) and forest (2.5%) zones. CONCLUSIONS This study reports high outdoor resting densities of An. gambiae and An. coluzzii with high kdr west mutation frequencies, and the presence of malaria vectors indoors despite the use of long-lasting insecticidal nets and indoor residual spraying. Continuous monitoring of changes in the resting behavior of mosquitoes and the implementation of complementary malaria control interventions that target outdoor resting Anopheles mosquitoes are necessary in Ghana.
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Affiliation(s)
- Akua Obeng Forson
- Department of Medical Laboratory Science, School of Biomedical and Allied Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana
| | - Isaac A. Hinne
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Shittu B. Dhikrullahi
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Isaac Kwame Sraku
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Abdul Rahim Mohammed
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Simon K. Attah
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Yaw Asare Afrane
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
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Omotayo AI, Dogara MM, Sufi D, Shuaibu T, Balogun J, Dawaki S, Muktar B, Adeniyi K, Garba N, Namadi I, Adam HA, Adamu S, Abdullahi H, Sulaiman A, Oduola AO. High pyrethroid-resistance intensity in Culex quinquefasciatus (Say) (Diptera: Culicidae) populations from Jigawa, North-West, Nigeria. PLoS Negl Trop Dis 2022; 16:e0010525. [PMID: 35727843 PMCID: PMC9249174 DOI: 10.1371/journal.pntd.0010525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 07/01/2022] [Accepted: 05/20/2022] [Indexed: 11/26/2022] Open
Abstract
This study examined pyrethroid resistance intensity and mechanisms in Culex quinquefasciatus (Say) (Diptera: Culicidae) populations from Jigawa, North-West Nigeria. Resistance statuses to permethrin, lambda-cyhalothrin and alphacypermethrin were determined with both WHO and CDC resistance bioassays. Synergist assay was conducted by pre-exposing the populations to Piperonyl butoxide (PBO) using the WHO method. Resistance intensities to 2x, 5x and 10x of diagnostic concentrations were determined with the CDC bottle method. Species analysis and presence of knockdown mutation (Leu-Phe) were done using Polymerase Chain Reaction (PCR). Results showed that Cx. quinquefasciatus was the only Culex spp. present and “Kdr-west” mutation was not detected in all analyzed samples. Using WHO method, Cx. quinquefasciatus resistance to permethrin was detected in Dutse (12.2%) and Kafin-Hausa (77.78%). Lambda-cyhalothrin resistance was recorded only in Kafin-Hausa (83.95%) with resistance suspected in Ringim (90%). Resistance to alphacypermethrin was recorded in all locations. Pre-exposure to PBO led to 100% mortality to alphacypermethrin and lambda-cyhalothrin in Ringim while mortality to permethrin and alphacypermethrin in Dutse increased from 12.2% to 97.5% and 64.37% to 79.52% respectively. Using CDC bottle bioassay, resistance was also recorded in all populations and the result shows a significant positive correlation (R2 = 0.728, p = 0.026) with the result from the WHO bioassay. Results of resistance intensity revealed a very high level of resistance in Kafin-Hausa with susceptibility to lambda-cyhalothrin and alphacypermethrin not achieved at 10x of diagnostic doses. Resistance intensity was also high in Dutse with susceptibility to all insecticides not achieved at 5x of diagnostic doses. Widespread and high intensity of resistance in Cx. quinquefasciatus from North-West Nigeria is a major threat to the control of diseases transmitted by Culex and other mosquito species. It is a challenge that needs to be adequately addressed so as to prevent the failure of pyrethroid-based vector control tools. Development of resistance to insecticide by mosquitoes has been identified to be a major challenge in the prevention and control of diseases transmitted by mosquitoes. This informs this study that investigated the level of resistance of Culex mosquitoes from Jigawa, North-West Nigeria to Pyrethroids. The main type of Culex mosquitoes found in the sampled area was Cx. quinquefasciatus. The Cx. quinquefasciatus populations were found to be resistant to permethrin, lambda-cyhalothrin and alphacypermethrin. Resistance in Cx. quinquefasciatus from the three LGAs is more pronounced to alphacypermethrin. The methods employed by the mosquitoes in developing resistance involve detoxification of the insecticides by metabolic enzymes. Cx. quinquefasciatus from the three LGAs were observed to be highly resistant and can withstand multiple of the recommended doses. This development whereby Cx. quinquefasciatus populations were highly resistant to these recommended insecticides is of serious concern as it can lead to failure of all efforts geared towards prevention and control of diseases transmitted by Culex mosquitoes in North-West Nigeria.
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Affiliation(s)
- Ahmed Idowu Omotayo
- Molecular Entomology and Vector Control Research Laboratory, Department of Public Health and Epidemiology, Nigeria Institute of Medical Research, Yaba, Lagos, Nigeria
- Department of Zoology, Faculty of Life Sciences, University of Ilorin, Ilorin, Kwara State, Nigeria
- * E-mail:
| | - Musa Mustapha Dogara
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Danjuma Sufi
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Tasiu Shuaibu
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Joshua Balogun
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Salwa Dawaki
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Bature Muktar
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Kamoru Adeniyi
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Nura Garba
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Isah Namadi
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Hafiz Abdullahi Adam
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Shuaibu Adamu
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
| | - Hamza Abdullahi
- Department of Biological Sciences, Federal University Kashere, Gombe State, Nigeria
| | - Abubakar Sulaiman
- Department of Biological Sciences, Federal University Dutse, Dutse, Jigawa State, Nigeria
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Attractive Sugar Bait Formulation for Development of Attractive Toxic Sugar Bait for Control of Aedes aegypti (Linnaeus). J Trop Med 2022; 2022:2977454. [PMID: 35832334 PMCID: PMC9273391 DOI: 10.1155/2022/2977454] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/26/2022] [Indexed: 11/17/2022] Open
Abstract
Background Attractive toxic sugar bait (ATSB), based on “attract and kill” approach, is a novel and promising strategy for mosquito control. Formulation of an attractive sugar bait (ASB) solution by selecting an efficient olfaction stimulant and preparation of an optimized sugar-attractant dosage is a significant component for the success of the approach. Methods Current study evaluated relative potential of nine ASBs, formulated by combination of sugar and fresh fruit juices (guava, mango, muskmelon, orange, papaya, pineapple, plum, sweet lemon, and watermelon) in attracting Aedes aegypti adults. Freshly extracted and 48-hour-fermented juices were combined with 10% sucrose solution (w/v) in 1 : 1 ratio. Cage bioassays were conducted against two laboratory strains (susceptible: AND-Aedes aegypti; deltamethrin-selected: AND-Aedes aegypti-DL10) and two field-collected strains (Shahdara strain of Aedes aegypti: SHD-Delhi; Govindpuri strain of Aedes aegypti: GVD-Delhi). Each of the nine ASBs was assayed, individually or in groups of three, for its attraction potential based on the relative number of mosquito landings. The data were analysed for statistical significance using PASW (SPSS) software 19.0 program. Results The prescreening bioassay with individual ASB revealed significantly higher efficacy of ASB containing guava/plum/mango juice than that containing six other juices (p < 0.05) against both the laboratory and field strains. The bioassay with three ASBs kept in one cage, one of the effective ASBs and two others randomly selected ASBs, also showed good attractancy of the guava/plum/mango juice-ASB (p < 0.05). The postscreening assays with these three ASBs revealed maximum attractant potential of guava juice-sucrose combination for all the four strains of Ae. aegypti. Conclusion. Guava juice-ASB showed the highest attractancy against both laboratory and field-collected strains of Ae. aegypti and can be used to formulate ATSB by combining with a toxicant. The field studies with these formulations will ascertain their efficacy and possible use in mosquito management programs.
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Mg-LDH Nanoclays Intercalated Fennel and Green Tea Active Ingredient: Field and Laboratory Evaluation of Insecticidal Activities against Culex pipiens and Their Non-Target Organisms. Molecules 2022; 27:molecules27082424. [PMID: 35458623 PMCID: PMC9028813 DOI: 10.3390/molecules27082424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 03/26/2022] [Accepted: 03/31/2022] [Indexed: 12/05/2022] Open
Abstract
(1) Background: Mosquito control with essential oils is a growing demand. This work evaluated the novel larvicidal and adulticidal activity of fennel and green tea oils and their Layered double hydroxides (LDHs) nanohybrid against Culex pipiens (Cx. pipiens) in both laboratory and field conditions and evaluated their effect against non-target organisms; (2) Methods: Two types of nanoclays, MgAl-LDH and NiAl-LDH were synthesized and characterized using PXRD, TEM and SEM, whereas their elemental analysis was accomplished by SEM-EDX; (3) Results: Mg and Ni LDHs were synthesized by the co-precipitation method. The adsorption and desorption of active ingredients were conducted using LC MS/MS, with reference to the SEM-EXD analysis. The desorption process of MgAl-LDH intercalated green tea oil was conducted using ethanol, and reveled significant peaks related to polyphenols and flavonoids like Vanillin, Catechin, Daidzein, Ellagic acid, Naringenin, Myricetin and Syringic acid with concentrations of 0.76, 0.73, 0.67, 0.59, 0.52, 0.44 and 0.42 μg/g, respectively. The larvicidal LC50 values of fennel oil, Mg-LDH-F, and Ni-LDH-F were 843.88, 451.95, 550.12 ppm, respectively, whereas the corresponding values of green tea were 938.93, 530.46, and 769.94 ppm. The larval reduction percentage of fennel oil and Mg-LDH-F reached 90.1 and 96.2%, 24 h PT and their persistence reached five and seven days PT, respectively. The reduction percentage of green tea oil and Mg-LDH-GT reached 88.00 and 92.01%, 24 h PT and their persistence reached five and six days PT, respectively. Against adults, Mg-LDH-GT and Ni-LDH-GT were less effective than green tea oil as their LC95 values were 5.45, 25.90, and 35.39%, respectively. The reduction in adult density PT with fennel oil, Mg-LDH-F, green tea oil, and Mg-LDH-GT reached 83.1, 100, 77.0, and 99.0%, respectively, 24 h PT and were effective for three days. Mg-LDH-GT and Mg-LDH-F increased the predation Cybister tripunctatus (71% and 69%), respectively; (4) Conclusions: For the first time, Mg-LDH-GT and Mg-LDH-F was the best system loaded with relatively good desorption release to its active ingredients and significantly affected Cx. pipiens larvae and adults in both laboratory and field circumstances, and it could be included in mosquito control.
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Nanostructured Lipid Carriers (NLC) for Biologically Active Green Tea and Fennel Natural Oils Delivery: Larvicidal and Adulticidal Activities against Culex pipiens. Molecules 2022; 27:molecules27061939. [PMID: 35335302 PMCID: PMC8951010 DOI: 10.3390/molecules27061939] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/10/2022] [Accepted: 03/14/2022] [Indexed: 01/24/2023] Open
Abstract
(1) Background: The control of mosquitoes with essential oils is a growing demand. (2) Methods: This study evaluated the novel larvicidal and adulticidal activity of fennel and green tea oils and their nanostructured lipid carriers (NLC) against Culex pipiens (C. pipiens) in the laboratory, field conditions and evaluated their effect against non-target organisms. SLN type II nanoformulations were synthesized and characterized using dynamic light scattering (DLS), zeta potential and transmission electron microscope. (3) Results: The synthesized NLCs showed spherical shaped, homogenous, narrow, and monomodal particle size distribution. The mortality percent (MO%) post-treatment (PT) with 2000 ppm for 24 h with fennel oil and NLC fennel (NLC-F) reached 85% (LC50 = 643.81 ppm) and 100% (LC50 = 251.71), whereas MO% for green tea oil and NLC green tea (NLC-GT) were 80% (LC50 = 746.52 ppm) and 100% (LC50 = 278.63 ppm), respectively. Field trial data showed that the larval reduction percent of fennel oil and NLC-F reached 89.8% and 97.4%, 24 h PT and the reduction percent of green tea oil and NLC-GT reached 89% and 93%, 24 h PT with persistence reached 8 and 7 days, for NLC-F and NLC-GT, respectively. The adulticidal effects showed that NLC-F and NLC-GT (100% mortality) were more effective than fennel and green tea oils (90.0% and 83.33%), with 24 h PT, respectively. Moreover, their reduction of adult density after spraying with LC95 X2 for 15 min, with fennel oil, NLC-F, and green tea oil, NLC-GT were 83.6%, 100%, 79.1%, and 100%, respectively, with persistence (>50%) lasting for three days. The predation rate of the mosquitofish, Gambusia affinis, and the bug, Sphaerodema urinator, was not affected in both oil and its NLC, while the predation rate of the beetle, Cybister tripunctatus increased (66% and 68.3%) by green tea oil and NLC-GT, respectively. (4) Conclusions: NLCs nanoformulation encapsulated essential oils was prepared successfully with unique properties of size, morphology, and stability. In vitro larvicidal and adulticidal effects against C. pipiens supported with field evaluations have been performed using essential oils and their nanoformulations. The biological evaluation of nanoformulations manifested potential results toward both larvicidal and adulticidal compared to the essential oils themselves, especially NLC encapsulated fennel oil which had promising larvicidal and adulticidal activity.
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Baz MM, Selim A, Radwan IT, Alkhaibari AM, Khater HF. Larvicidal and adulticidal effects of some Egyptian oils against Culex pipiens. Sci Rep 2022; 12:4406. [PMID: 35292687 PMCID: PMC8924206 DOI: 10.1038/s41598-022-08223-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 02/24/2022] [Indexed: 01/10/2023] Open
Abstract
Mosquitoes and mosquito-borne diseases represent an increasing global challenge. Plant extract and/or oils could serve as alternatives to synthetic insecticides. The larvicidal effects of 32 oils (1000 ppm) were screened against the early 4th larvae of Culex pipiens and the best oils were evaluated against adults and analyzed by gas chromatography-mass spectrometry (GC mass) and HPLC. All oils had larvicidal activity (60.0-100%, 48 h Post-treatment, and their Lethal time 50 (LT50) values ranged from 9.67 (Thymus vulgaris) to 37.64 h (Sesamum indicum). Oils were classified as a highly effective group (95-100% mortalities), including Allium sativum, Anethum graveolens, Camellia sinensis, Foeniculum vulgare, Nigella sativa, Salvia officinalis, T. vulgaris, and Viola odorata. The moderately effective group (81-92% mortalities) included Boswellia serrata, Cuminum cyminum, Curcuma aromatic, Allium sativum, Melaleuca alternifolia, Piper nigrum, and Simmondsia chinensis. The least effective ones were C. sativus and S. indicum. Viola odorata, Anethum graveolens, T. vulgaris, and N. sativa provide 100% adult mortalities PT with 10, 25, 20, and 25%. The mortality percentages of the adults subjected to 10% of oils (H group) were 48.89%, 88.39%, 63.94%, 51.54%, 92.96%, 44.44%, 72.22%, and 100% for A. sativum, An. graveolens, C. sinensis, F. vulgare, N. sativa, S. officinalis, T. vulgaris, and V. odorata, respectively. Camellia sinensis and F. vulgare were the most potent larvicides whereas V. odorata, T. vulgaris, An. graveolens and N. sativa were the best adulticides and they could be used for integrated mosquito control.
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Affiliation(s)
- Mohamed M. Baz
- grid.411660.40000 0004 0621 2741Department of Entomology, Faculty of Science, Benha University, Benha, 13518 Egypt
| | - Abdelfattah Selim
- grid.411660.40000 0004 0621 2741Department of Animal Medicine (Infectious Diseases), Faculty of Veterinary Medicine, Benha University, Toukh, 13736 Egypt
| | - Ibrahim Taha Radwan
- grid.440865.b0000 0004 0377 3762Supplementary General Sciences Department, Faculty of Oral and Dental Medicine, Future University in Egypt, P.O. Box 11835, Cairo, Egypt
| | - Abeer Mousa Alkhaibari
- grid.440760.10000 0004 0419 5685Department of Biology, Faculty of Science, University of Tabuk, Tabuk, 71491 Kingdom of Saudi Arabia
| | - Hanem F. Khater
- grid.411660.40000 0004 0621 2741Department of Parasitology, Faculty of Veterinary Medicine, Benha University, Toukh, 13736 Egypt
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Telleria EL, Azevedo-Brito DA, Kykalová B, Tinoco-Nunes B, Pitaluga AN, Volf P, Traub-Csekö YM. Leishmania infantum Infection Modulates the Jak-STAT Pathway in Lutzomyia longipalpis LL5 Embryonic Cells and Adult Females, and Affects Parasite Growth in the Sand Fly. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.747820] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Phlebotomine sand flies (Diptera, Psychodidae) belonging to the Lutzomyia genus transmit zoonoses in the New World. Lutzomyia longipalpis is the main vector of Leishmania infantum, which is the causative agent of visceral leishmaniasis in Brazil. To identify key molecular aspects involved in the interaction between vector and pathogens and contribute to developing disease transmission controls, we investigated the sand fly innate immunity mediated by the Janus kinase/signal transducer and activator of transcription (Jak-STAT) pathway in response to L. infantum infection. We used two study models: L. longipalpis LL5 embryonic cells co-cultured with L. infantum and sand fly females artificially infected with the parasite. We used qPCR to follow the L. longipalpis gene expression of molecules involved in the Jak-STAT pathway. Also, we modulated the Jak-STAT mediated immune response to understand its role in Leishmania parasite infection. For that, we used RNAi to silence the pathway regulators, protein inhibitor of activated STATs (PIAS) in LL5 cells, and STAT in adult females. In addition, the pathway suppression effect on parasite development within the vector was assessed by light microscopy in late-phase infection. The silencing of the repressor PIAS in LL5 cells led to a moderate increase in a protein tyrosine phosphatase 61F (PTP61F) expression. It suggests a compensatory regulation between these two repressors. L. infantum co-culture with LL5 cells upregulated repressors PIAS, suppressor of cytokine signaling (SOCS), and PTP61F. It also downmodulated virus-induced RNA-1 (VIR-1), a pathway effector, indicating that the parasite could repress the Jak-STAT pathway in LL5 cells. In Leishmania-infected L. longipalpis females, STAT and the antimicrobial peptide attacin were downregulated on the third day post-infection, suggesting a correlation that favors the parasite survival at the end of blood digestion in the sand fly. The antibiotic treatment of infected females showed that the reduction of gut bacteria had little effect on the Jak-STAT pathway regulation. STAT gene silencing mediated by RNAi reduced the expression of inducible nitric oxide synthase (iNOS) and favored Leishmania growth in sand flies on the first day post-infection. These results indicate that STAT participated in the iNOS regulation with subsequent effect on parasite survival.
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Khalil SMS, Munawar K, Alahmed AM, Mohammed AMA. RNAi-Mediated Screening of Selected Target Genes Against Culex quinquefasciatus (Diptera: Culicidae). JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:2177-2185. [PMID: 34197598 DOI: 10.1093/jme/tjab114] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Indexed: 06/13/2023]
Abstract
Culex quinquefasciatus, a member of the Culex pipiens complex, is widespread in Saudi Arabia and other parts of the world. It is a vector for lymphatic filariasis, Rift Valley fever, and West Nile virus. Studies have shown the deleterious effect of RNA interference (RNAi)-mediated knockdown of various lethal genes in model and agricultural pest insects. RNAi was proposed as a tool for mosquito control with a focus on Aedes aegypti and Anopheles gambiae. In this study, we examined the effect of RNAi of selected target genes on both larval mortality and adult emergence of Cx. quinquefasciatus through two delivery methods: soaking and nanoparticles. Ten candidate genes were selected for RNAi based on their known lethal effect in other insects. Disruption of three genes, chitin synthase-1, inhibitor of apoptosis 1, and vacuolar adenosine triphosphatase, resulted in the highest mortality among the selected genes using the two treatment methods. Silencing the other seven genes resulted in a medium to low mortality in both assays. These three genes are also active against a wide range of insects and could be used for RNAi-based mosquito control in the future.
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Affiliation(s)
- Sayed M S Khalil
- Plant Protection Department, College of Food and Agricultural Sciences, King Saud University, Riyadh, Saudi Arabia
- Agricultural Genetic Engineering Research Institute, Agricultural Research Center, 9 Gamaa Street, Giza, Egypt
| | - Kashif Munawar
- Plant Protection Department, College of Food and Agricultural Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Azzam M Alahmed
- Plant Protection Department, College of Food and Agricultural Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Ahmed M A Mohammed
- Agricultural Genetic Engineering Research Institute, Agricultural Research Center, 9 Gamaa Street, Giza, Egypt
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Akorli J, Akorli EA, Tetteh SNA, Amlalo GK, Opoku M, Pwalia R, Adimazoya M, Atibilla D, Pi-Bansa S, Chabi J, Dadzie SK. Microsporidia MB is found predominantly associated with Anopheles gambiae s.s and Anopheles coluzzii in Ghana. Sci Rep 2021; 11:18658. [PMID: 34545153 PMCID: PMC8452686 DOI: 10.1038/s41598-021-98268-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 09/07/2021] [Indexed: 11/16/2022] Open
Abstract
A vertically transmitted microsporidian, Microsporidia MB, with the ability to disrupt Plasmodium development was reported in Anopheles arabiensis from Kenya, East Africa. To demonstrate its range of incidence, archived DNA samples from 7575 Anopheles mosquitoes collected from Ghana were screened. MB prevalence was observed at 1.8%. An. gambiae s.s constituted 87% of positive mosquitoes while the remaining were from An. coluzzii. Both sibling species had similar positivity rates (24% and 19%; p = 0.42) despite the significantly higher number of An. gambiae s.s analysed (An. gambiae s.s = 487; An. coluzzii = 94; p = 0.0005). The microsporidian was also more prevalent in emerged adults from field-collected larvae than field-caught adults (p < 0.0001) suggestive of an efficient vertical transmission and/or horizontal transfer among larvae. This is the first report of Microsporidia MB in Anopheles mosquitoes in West Africa. It indicates possible widespread among malaria vector species and warrants investigations into the symbiont’s diversity across sub-Saharan Africa.
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Affiliation(s)
- Jewelna Akorli
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana.
| | - Esinam Abla Akorli
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Seraphim Naa Afoley Tetteh
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Godwin Kwame Amlalo
- Vestergaard-NMIMR Vector Labs, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Millicent Opoku
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Rebecca Pwalia
- Vestergaard-NMIMR Vector Labs, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Michelle Adimazoya
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Dorcas Atibilla
- Entomology Unit, Department of Clinical Laboratory, Kintampo Health Research Centre, P.O. Box 200, Kintampo, Ghana
| | - Sellase Pi-Bansa
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Joseph Chabi
- Vestergaard-NMIMR Vector Labs, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
| | - Samuel Kweku Dadzie
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
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Taktak NEM, Badawy MEI, Awad OM, Abou El-Ela NE, Abdallah SM. Enhanced mosquitocidal efficacy of pyrethroid insecticides by nanometric emulsion preparation towards Culex pipiens larvae with biochemical and molecular docking studies. J Egypt Public Health Assoc 2021; 96:21. [PMID: 34264427 PMCID: PMC8282878 DOI: 10.1186/s42506-021-00082-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 06/02/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND The growing threat of vector-borne diseases and environmental pollution with conventional pesticides has led to the search for nanotechnology applications to prepare alternative products. METHODS In the current study, four pyrethroid insecticides include alpha-cypermethrin, deltamethrin, lambda-cyhalothrin, and permethrin were incorporated into stable nanoemulsions. The optimization of nanoemulsions is designed based on the active ingredient, solvent, surfactant, sonication time, sonication cycle, and sonication energy by factorial analysis. The nanoscale emulsions' droplet size and morphology were measured by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. The toxicity of nanoemulsions against Culex pipiens larvae was evaluated and compared with the technical and commercial formulations. The in vitro assay of adenosine triphosphatase (ATPase), carboxylesterase (CaE), and glutathione-S-transferase (GST) were also investigated. Furthermore, molecular docking was examined to assess the binding interactions between the tested pyrethroids and the target enzymes. Also, an ecotoxicological assessment of potential effects of the tested products on the freshwater alga Raphidocelis subcapitata was determined according to OECD and EPA methods. The emulsifible concentration (EC50) and NOEC (no observed effect concentration) values were estimated for each insecticide and graded according to the GHS to determine the risk profile in aquatic life. RESULTS The mean droplet diameter and zeta potential of the prepared pyrethroid nanoemulsions were found to be in the range of 72.00-172.00 nm and - 0.539 to - 15.40 mV, respectively. All insecticides' nanoemulsions showed significantly high toxicity (1.5-2-fold) against C. pipiens larvae compared to the technical and EC. The biochemical activity data proved that all products significantly inhibited ATPase. However, GST and CaE were significantly activated. Docking results proved that the pyrethroids exhibited a higher binding affinity with CaE and GST than ATPase. The docking scores ranged from - 4.33 to - 10.01 kcal/mol. Further, the biosafety studies of the nanopesticides in comparison with the active ingredient and commercial EC were carried out against the freshwater alga R. subcapitata and the mosquitocidal concentration of nanopesticides was found to be non-toxic. CONCLUSION The mosquitocidal efficacy of nano-pyrethroids formulated in a greener approach could become an alternative to using conventional pesticide application in an environmentally friendly manner.
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Affiliation(s)
- Nehad E M Taktak
- Department of Tropical Health, High Institute of Public Health, Alexandria University, 165 El-Horreya Ave., 21561-El-Hadara, Alexandria, Egypt
| | - Mohamed E I Badawy
- Department of Pesticide Chemistry and Technology, Laboratory of Pesticide Residues Analysis, Faculty of Agriculture, Alexandria University, 21545-El-Shatby, Alexandria, Egypt.
| | - Osama M Awad
- Department of Tropical Health, High Institute of Public Health, Alexandria University, 165 El-Horreya Ave., 21561-El-Hadara, Alexandria, Egypt
| | - Nadia E Abou El-Ela
- Department of Tropical Health, High Institute of Public Health, Alexandria University, 165 El-Horreya Ave., 21561-El-Hadara, Alexandria, Egypt
| | - Salwa M Abdallah
- Mammalian and Aquatic Toxicology Department, Central Agricultural Pesticides Laboratory (CAPL), Agricultural Research Center (ARC), Dokki, 12618, Egypt
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Huxley PJ, Murray KA, Pawar S, Cator LJ. The effect of resource limitation on the temperature dependence of mosquito population fitness. Proc Biol Sci 2021; 288:20203217. [PMID: 33906411 PMCID: PMC8079993 DOI: 10.1098/rspb.2020.3217] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/31/2021] [Indexed: 12/27/2022] Open
Abstract
Laboratory-derived temperature dependencies of life-history traits are increasingly being used to make mechanistic predictions for how climatic warming will affect vector-borne disease dynamics, partially by affecting abundance dynamics of the vector population. These temperature-trait relationships are typically estimated from juvenile populations reared on optimal resource supply, even though natural populations of vectors are expected to experience variation in resource supply, including intermittent resource limitation. Using laboratory experiments on the mosquito Aedes aegypti, a principal arbovirus vector, combined with stage-structured population modelling, we show that low-resource supply in the juvenile life stages significantly depresses the vector's maximal population growth rate across the entire temperature range (22-32°C) and causes it to peak at a lower temperature than at high-resource supply. This effect is primarily driven by an increase in juvenile mortality and development time, combined with a decrease in adult size with temperature at low-resource supply. Our study suggests that most projections of temperature-dependent vector abundance and disease transmission are likely to be biased because they are based on traits measured under optimal resource supply. Our results provide compelling evidence for future studies to consider resource supply when predicting the effects of climate and habitat change on vector-borne disease transmission, disease vectors and other arthropods.
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Affiliation(s)
- Paul J. Huxley
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, UK
| | - Kris A. Murray
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, UK
- MRC Unit The Gambia at London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - Samraat Pawar
- Department of Life Sciences, Imperial College London, Ascot, UK
| | - Lauren J. Cator
- Department of Life Sciences, Imperial College London, Ascot, UK
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