1
|
Tokumaru S, Tokushima Y, Ito S, Yamaguchi T, Shimoda M. Advanced methods for insect nets: red-colored nets contribute to sustainable agriculture. Sci Rep 2024; 14:2255. [PMID: 38355700 PMCID: PMC10866966 DOI: 10.1038/s41598-024-52108-1] [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: 05/23/2023] [Accepted: 01/13/2024] [Indexed: 02/16/2024] Open
Abstract
Development of advanced pest control methods that do not rely on insecticides is an important issue for sustainable agriculture. Particularly with regards to micro pests that are not only highly resistant to various insecticides but also because we are running out of options for which insecticide to use against them, resulting in enormous economic damage worldwide. Here we report that the effectiveness of the conventional insect net can be greatly advanced by changing their color to red that helps significantly reduce pesticide use. We demonstrate the red effect using Onion thrips, Thrips tabaci a main vector of Iris Yellow Spot Virus (IYSV) and Tomato Spotted Wilt Virus (TSWV) that cause serious damage to various vegetables. New red nets succeeded in suppressing the invasion rates and damages (white spots on the leaves) in a Welsh onion greenhouse with minimum use of pesticides. We discuss how red nets are compatible with labor-saving, sustainable agriculture and the future potential of "optical pest control" based on insect color vision and its behavioral response.
Collapse
Affiliation(s)
- Susumu Tokumaru
- Kyoto Prefectural Agriculture, Forestry and Fisheries Technology Center, Kameoka, Kyoto, 621-0806, Japan.
| | | | - Shun Ito
- Kyoto Prefectural Agriculture, Forestry and Fisheries Technology Center, Kameoka, Kyoto, 621-0806, Japan
| | - Terumi Yamaguchi
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Masami Shimoda
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan.
| |
Collapse
|
2
|
Abbott AJ, Matope A, Jones J, Voloshin V, Towers CE, Towers D, McCall PJ. Insecticidal roof barriers mounted on untreated bed nets can be as effective against Anopheles gambiae as regular insecticide-treated bed nets. Sci Rep 2023; 13:22080. [PMID: 38086842 PMCID: PMC10716170 DOI: 10.1038/s41598-023-48499-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Barrier bednets (BBnets), regular bednets with a vertical insecticidal panel to target mosquitoes above the bednet roof, where they are most active, have the potential to improve existing Insecticidal Treated Bednets (ITNs), by reducing the quantity of insecticide required per net, reducing the toxic risks to those using the net, potentially increasing insecticide choice. We evaluated the performance of PermaNet 3.0 (P3) and untreated (Ut) bed nets with and without pyrethroid and piperonyl butoxide roof barriers in killing pyrethroid-resistant and susceptible Anopheles gambiae, simultaneously video-recording mosquito flight tracks. Bioassay results showed that treated roof barriers, particularly the longitudinal P3 barrier (P3L) could be an effective addition to a bed net: P3 + P3L were consistently significantly more effective than the reference P3 bednet while performance of untreated nets could be raised to equal that of the reference P3 following the addition of a P3 barrier. The BBnet's potential to augment existing bednets and enhance their performance is considered.
Collapse
Affiliation(s)
- Anthony J Abbott
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Agnes Matope
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Jeff Jones
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Vitaly Voloshin
- Optical Engineering Group, School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
| | - Catherine E Towers
- Optical Engineering Group, School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
| | - David Towers
- Optical Engineering Group, School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
| | - Philip J McCall
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK.
| |
Collapse
|
3
|
Borkens Y. Malaria & mRNA Vaccines: A Possible Salvation from One of the Most Relevant Infectious Diseases of the Global South. Acta Parasitol 2023; 68:916-928. [PMID: 37828249 PMCID: PMC10665248 DOI: 10.1007/s11686-023-00712-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: 10/10/2022] [Accepted: 08/01/2023] [Indexed: 10/14/2023]
Abstract
Malaria is one of the most dangerous infectious diseases in the world. It occurs in tropical and subtropical regions and affects about 40% of the world´s population. In endemic regions, an estimated 200 million people contract malaria each year. Three-quarters of all global deaths (about 600 per year) are children under 5 years of age. Thus, malaria is one of the most relevant tropical and also childhood diseases in the world. Thanks to various public health measures such as vector control through mosquito nets or the targeted use of insecticides as well as the use of antimalarial prophylaxis drugs, the incidence has already been successfully reduced in recent years. However, to reduce the risk of malaria and to protect children effectively, further measures are necessary. An important part of these measures is an effective vaccination against malaria. However, the history of research shows that the development of an effective malaria vaccine is not an easy undertaking and is associated with some complications. Research into possible vaccines began as early as the 1960s. However, the results achieved were rather sobering and the various vaccines fell short of their expectations. It was not until 2015 that the vaccine RTS,S/AS01 received a positive evaluation from the European Medicines Agency. Since then, the vaccine has been tested in Africa. However, with the COVID-19 pandemic, there are new developments in vaccine research that could also benefit malaria research. These include, among others, the so-called mRNA vaccines. Already in the early 1990s, an immune response triggered by an mRNA vaccine was described for the first time. Since then, mRNA vaccines have been researched and discussed for possible prophylaxis. However, it was not until the COVID-19 pandemic that these vaccines experienced a veritable progress. mRNA vaccines against SARS-CoV-2 were rapidly developed and achieved high efficacy in studies. Based on this success, it is not surprising that companies are also focusing on other diseases and pathogens. Besides viral diseases, such as influenza or AIDS, malaria is high on this list. Many pharmaceutical companies (including the German companies BioNTech and CureVac) have already confirmed that they are researching mRNA vaccines against malaria. However, this is not an easy task. The aim of this article is to describe and discuss possible antigens that could be considered for mRNA vaccination. However, this topic is currently still very speculative.
Collapse
Affiliation(s)
- Yannick Borkens
- Charité, Charitéplatz 1, 10117, Berlin, Germany.
- Humboldt-Universität zu Berlin, Unter den Linden 6, 10117, Berlin, Germany.
| |
Collapse
|
4
|
Facchinelli L, Alsharif B, Jones JD, Matope A, Barbosa RMR, Ayres CFJ, McCall PJ. Mapping Aedes aegypti indoor resting behavior reveals a preference vulnerable to householder-led vector control. PNAS NEXUS 2023; 2:pgad226. [PMID: 37497049 PMCID: PMC10368326 DOI: 10.1093/pnasnexus/pgad226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 05/04/2023] [Accepted: 06/28/2023] [Indexed: 07/28/2023]
Abstract
Many mosquito vectors rest inside human habitations, a behavioral trait that is exploited for vector control by indoor residual spraying (IRS) of interior walls with insecticide. Although IRS and its refined version targeted IRS are very effective against Aedes aegypti, they are expensive and logistically challenging to deliver in densely populated urban areas where outbreaks of dengue and other arboviruses are the greatest challenge. In experiments in Recife, Brazil, we set out to quantify the indoor resting behavior of Ae. aegypti at a level beyond that previously reported. We found that significantly more Ae. aegypti males, unfed and fed females visited the base of walls (height 0-20 cm, corresponding to 12.3% of the total wall surface) more frequently than upper wall areas, with the difference more pronounced at higher temperatures. When the lowest 20 cm of the walls was treated with an appropriate insecticide and colored black, we recorded up to 85% cumulative mortality after 24-h exposure in the experimental room. The findings are significant because feasibly, householders could treat this small and accessible target zone manually, without the need for visits by costly IRS teams or equipment, reducing insecticide use and enabling communities to actively protect their own indoor environment.
Collapse
Affiliation(s)
| | - Bashir Alsharif
- Departamento de Entomologia, Instituto Aggeu Magalhães, Fiocruz Pernambuco, 50.740-465 Recife (PE), Brazil
| | - Jeff D Jones
- Vector Biology Department, Liverpool School of Tropical Medicine, L15QA, Liverpool, UK
| | - Agnes Matope
- Vector Biology Department, Liverpool School of Tropical Medicine, L15QA, Liverpool, UK
| | - Rôsangela M R Barbosa
- Departamento de Entomologia, Instituto Aggeu Magalhães, Fiocruz Pernambuco, 50.740-465 Recife (PE), Brazil
| | - Constância F J Ayres
- Departamento de Entomologia, Instituto Aggeu Magalhães, Fiocruz Pernambuco, 50.740-465 Recife (PE), Brazil
| | | |
Collapse
|
5
|
Perugini E, Guelbeogo WM, Guglielmo F, Poggi C, Gabrieli E, Ranson H, Della Torre A, Pombi M. The interplay between malaria vectors and human activity accounts for high residual malaria transmission in a Burkina Faso village with universal ITN coverage. Parasit Vectors 2023; 16:101. [PMID: 36922855 PMCID: PMC10015820 DOI: 10.1186/s13071-023-05710-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/22/2023] [Indexed: 03/17/2023] Open
Abstract
BACKGROUND Mosquito and human behaviour interaction is a key determinant of the maximum level of protection against malaria that can be provided by insecticide-treated nets (ITNs). Nevertheless, scant literature focuses on this interaction, overlooking a fundamental factor for efficient malaria control. This study aims to estimate malaria transmission risk in a Burkina Faso village by integrating vector biting rhythms with some key information about human habits. METHODS Indoor/outdoor human landing catches were conducted for 16 h (16:00-08:00) during 8 nights (September 2020) in Goden village. A survey about net usage and sleeping patterns was submitted to half the households (October-December 2020). A subsample of collected specimens of Anopheles gambiae sensu lato was molecularly processed for species identification, Plasmodium detection from heads-thoraxes and L1014F pyrethroid-resistance allele genotyping. Hourly mosquito abundance was statistically assessed by GLM/GAM, and the entomological inoculation rate (EIR) was corrected for the actual ITN usage retrieved from the questionnaire. RESULTS Malaria transmission was mainly driven by Anopheles coluzzii (68.7%) followed by A. arabiensis (26.2%). The overall sporozoite rate was 2% with L1014F estimated frequency of 0.68 (N = 1070 out of 15,201 A. gambiae s.l. collected). No major shift in mosquito biting rhythms in response to ITN or differences between indoor and outdoor catches were detected. Impressive high biting pressure (mean 30.3 mosquitoes/person/hour) was exerted from 20:00 to 06:00 with a peak at 4:00. Human survey revealed that nearly all inhabitants were awake before 20:00 and after 7:00 and at least 8.7% had no access to bednets. Adjusting for anthropological data, the EIR dropped from 6.7 to 1.2 infective bites/person/16 h. In a scenario of full net coverage and accounting only for the human sleeping patterns, the daily malaria transmission risk not targetable by ITNs was 0.69 infective bites. CONCLUSIONS The high mosquito densities and interplay between human/vector activities means that an estimated 10% of residual malaria transmission cannot be prevented by ITNs in the village. Locally tailored studies, like the current one, are essential to explore the heterogeneity of human exposure to infective bites and, consequently, to instruct the adoption of new vector control tools strengthening individual and community protection.
Collapse
Affiliation(s)
- Eleonora Perugini
- Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italy
| | - Wamdaogo M Guelbeogo
- Centre National de Recherche et Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Federica Guglielmo
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Cristiana Poggi
- Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italy
| | - Eugenio Gabrieli
- Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italy
| | - Hilary Ranson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Marco Pombi
- Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italy.
| |
Collapse
|
6
|
Killeen GF, Sougoufara S. Getting ahead of insecticide-resistant malaria vector mosquitoes. Lancet 2023; 401:410-411. [PMID: 36706777 DOI: 10.1016/s0140-6736(23)00102-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 12/15/2022] [Indexed: 01/26/2023]
Affiliation(s)
- Gerry F Killeen
- School of Biological, Earth, and Environmental Sciences, University College Cork, Cork T23 N73K, Ireland.
| | - Seynabou Sougoufara
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, UK
| |
Collapse
|
7
|
Unwin HJT, Sherrard-Smith E, Churcher TS, Ghani AC. Quantifying the direct and indirect protection provided by insecticide treated bed nets against malaria. Nat Commun 2023; 14:676. [PMID: 36750566 PMCID: PMC9905482 DOI: 10.1038/s41467-023-36356-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 01/27/2023] [Indexed: 02/09/2023] Open
Abstract
Long lasting insecticidal nets (LLINs) provide both direct and indirect protection against malaria. As pyrethroid resistance evolves in mosquito vectors, it will be useful to understand how the specific benefits LLINs afford individuals and communities may be affected. Here we use modelling to show that there is no minimum LLIN usage needed for users and non-users to benefit from community protection. Modelling results also indicate that pyrethroid resistance in local mosquitoes will likely diminish the direct and indirect benefits from insecticides, leaving the barrier effects intact, but LLINs are still expected to provide enhanced benefit over untreated nets even at high levels of pyrethroid resistance.
Collapse
Affiliation(s)
- H Juliette T Unwin
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, UK.
| | - Ellie Sherrard-Smith
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, UK
| | - Thomas S Churcher
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, UK
| | - Azra C Ghani
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, UK
| |
Collapse
|
8
|
Lissenden N, Armistead JS, Gleave K, Irish SR, Martin JL, Messenger LA, Moore SJ, Ngufor C, Protopopoff N, Oxborough R, Spiers A, Lees RS. Developing Consensus Standard Operating Procedures (SOPs) to Evaluate New Types of Insecticide-Treated Nets. INSECTS 2021; 13:7. [PMID: 35055850 PMCID: PMC8778287 DOI: 10.3390/insects13010007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 12/15/2021] [Accepted: 12/17/2021] [Indexed: 11/30/2022]
Abstract
In response to growing concerns over the sustained effectiveness of pyrethroid-only based control tools, new products are being developed and evaluated. Some examples of these are dual-active ingredient (AI) insecticide-treated nets (ITNs) which contain secondary insecticides, or synergist ITNs which contain insecticide synergist, both in combination with a pyrethroid. These net types are often termed 'next-generation' insecticide-treated nets. Several of these new types of ITNs are being evaluated in large-scale randomized control trials (RCTs) and pilot deployment schemes at a country level. However, no methods for measuring the biological durability of the AIs or synergists on these products are currently recommended. In this publication, we describe a pipeline used to collate and interrogate several different methods to produce a singular 'consensus standard operating procedure (SOP)', for monitoring the biological durability of three new types of ITNs: pyrethroid + piperonyl butoxide (PBO), pyrethroid + pyriproxyfen (PPF), and pyrethroid + chlorfenapyr (CFP). This process, convened under the auspices of the Innovation to Impact programme, sought to align methodologies used for conducting durability monitoring activities of next-generation ITNs.
Collapse
Affiliation(s)
- Natalie Lissenden
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (K.G.); (R.S.L.)
- Innovation to Impact, Pembroke Place, Liverpool L3 5QA, UK;
| | - Jennifer S. Armistead
- U.S. President’s Malaria Initiative, U.S. Agency for International Development, Washington, DC 20547, USA;
| | - Katherine Gleave
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (K.G.); (R.S.L.)
| | - Seth R. Irish
- U.S. President’s Malaria Initiative, Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA; (S.R.I.); (L.A.M.)
| | - Jackline L. Martin
- Kilimanjaro Christian Medical University College, National Institute for Medical Research, Moshi P.O. Box 2240, Tanzania;
| | - Louisa A. Messenger
- U.S. President’s Malaria Initiative, Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA; (S.R.I.); (L.A.M.)
| | - Sarah J. Moore
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania;
- Nelson Mandela African Institution of Science and Technology, Arusha P.O. Box 477, Tanzania
- Vector Biology Unit, Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051 Basel, Switzerland
- Faculty of Science, University of Basel, St. Petersplatz 1, 4002 Basel, Switzerland
| | - Corine Ngufor
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK; (C.N.); (N.P.)
- Centre de Recherche Entomologique de Cotonou, Cotonou BP 2604, Benin
| | - Natacha Protopopoff
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK; (C.N.); (N.P.)
| | | | - Angus Spiers
- Innovation to Impact, Pembroke Place, Liverpool L3 5QA, UK;
| | - Rosemary S. Lees
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (K.G.); (R.S.L.)
- Innovation to Impact, Pembroke Place, Liverpool L3 5QA, UK;
| |
Collapse
|
9
|
Ingham VA, Brown F, Ranson H. Transcriptomic analysis reveals pronounced changes in gene expression due to sub-lethal pyrethroid exposure and ageing in insecticide resistance Anopheles coluzzii. BMC Genomics 2021; 22:337. [PMID: 33971808 PMCID: PMC8111724 DOI: 10.1186/s12864-021-07646-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 04/23/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria control is heavily reliant on the use of insecticides that target and kill the adult female Anopheline vector. The intensive use of insecticides of the pyrethroid class has led to widespread resistance in mosquito populations. The intensity of pyrethroid resistance in some settings in Africa means mosquitoes can contact bednets treated with this insecticide class multiple times with minimal mortality effects. Furthermore, both ageing and diel cycle have been shown to have large impacts on the resistance phenotype. Together, these traits may affect other aspects of vector biology controlling the vectorial capacity or fitness of the mosquito. RESULTS Here we show that sublethal exposure of a highly resistant Anopheles coluzzii population originally from Burkina Faso to the pyrethroid deltamethrin results in large and sustained changes to transcript expression. We identify five clear patterns in the data showing changes to transcripts relating to: DNA repair, respiration, translation, behaviour and oxioreductase processes. Further, we highlight differential regulation of transcripts from detoxification families previously linked with insecticide resistance, in addition to clear down-regulation of the oxidative phosphorylation pathway both indicative of changes in metabolism post-exposure. Finally, we show that both ageing and diel cycle have major effects on known insecticide resistance related transcripts. CONCLUSION Sub-lethal pyrethroid exposure, ageing and the diel cycle results in large-scale changes in the transcriptome of the major malaria vector Anopheles coluzzii. Our data strongly supports further phenotypic studies on how transcriptional changes such as reduced expression of the oxidative phosphorylation pathway or pyrethroid induced changes to redox state might impact key mosquito traits, such as vectorial capacity and life history traits.
Collapse
Affiliation(s)
- V A Ingham
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L35QA, UK. .,Present Address: Parasitology Unit, Centre for Infectious Diseases, Universitätsklinikum, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany.
| | - F Brown
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L35QA, UK.,Department of Epidemiology and Population Health, Institute of Infection and Global Health, Faculty of Health and Life Sciences, Leahurst Campus, University of Liverpool, Neston, CH647TE, UK
| | - H Ranson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L35QA, UK
| |
Collapse
|
10
|
Hall ML, McCall P, Towers CE, Towers DP. Improved three-dimensional localization of multiple small objects in close proximity in digital holography. APPLIED OPTICS 2021; 60:A285-A295. [PMID: 33690380 DOI: 10.1364/ao.404432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/17/2020] [Indexed: 06/12/2023]
Abstract
Using intensity gradient- or sparsity-based focus metrics, the ability to accurately localize the three-dimensional (3D) position of a small object in a digital holographic reconstruction of a large field of view is hindered in the presence of multiple nearby objects. A more accurate alternative method for 3D localization, based on evaluation of the complex reconstructed volume, is proposed. Simulations and experimental data demonstrate a reduction in depth positional error for single objects and a notably improved axial resolution of multiple objects in close proximity.
Collapse
|
11
|
Jones J, Murray GPD, McCall PJ. A minimal 3D model of mosquito flight behaviour around the human baited bed net. Malar J 2021; 20:24. [PMID: 33413370 PMCID: PMC7792054 DOI: 10.1186/s12936-020-03546-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 12/12/2020] [Indexed: 02/08/2023] Open
Abstract
Background Advances in digitized video-tracking and behavioural analysis have enabled accurate recording and quantification of mosquito flight and host-seeking behaviours, facilitating development of individual (agent) based models at much finer spatial scales than previously possible. Methods Quantified behavioural parameters were used to create a novel virtual testing model, capable of accurately simulating indoor flight behaviour by a virtual population of host-seeking mosquitoes as they interact with and respond to simulated stimuli from a human-occupied bed net. The model is described, including base mosquito behaviour, state transitions, environmental representation and host stimulus representation. Results In the absence of a bed net and human host bait, flight distribution of the model population was relatively uniform throughout the arena. Introducing an unbaited untreated bed net induced a change in distribution with an increase in landing events on the net surface, predominantly on the sides of the net. Adding the presence of a simulated human bait dramatically impacted flight distribution patterns, exploratory foraging and, the number and distribution of landing positions on the net, which were determined largely by the orientation of the human within. The model replicates experimental results with free-flying living mosquitoes at human-occupied bed nets, where contact occurs predominantly on the top surface of the net. This accuracy is important as it quantifies exposure to the lethal insecticide residues that may be unique to the net roof (or theoretically any other surface). Number of net contacts and height of contacts decreased with increasing attractant dispersal noise. Conclusions Results generated by the model are an accurate representation of actual mosquito behaviour recorded at and around a human-occupied bed net in untreated and insecticide-treated nets. This fine-grained model is highly flexible and has significant potential for in silico screening of novel bed net designs, potentially reducing time and cost and accelerating the deployment of new and more effective tools for protecting against malaria in sub-Saharan Africa.
Collapse
Affiliation(s)
- Jeff Jones
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA, Liverpool, UK
| | - Gregory P D Murray
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA, Liverpool, UK
| | - Philip J McCall
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA, Liverpool, UK.
| |
Collapse
|
12
|
Shepard DS, Odumah JU, Awolola ST. Cost-Effectiveness of PBO versus Conventional Long-Lasting Insecticidal Bed Nets in Preventing Symptomatic Malaria in Nigeria: Results of a Pragmatic Randomized Trial. Am J Trop Med Hyg 2020; 104:979-986. [PMID: 33350366 PMCID: PMC7941848 DOI: 10.4269/ajtmh.20-0956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/26/2020] [Indexed: 11/19/2022] Open
Abstract
Insecticide treated nets (ITNs) have been the major tool in halving malaria’s burden since 2000, but pyrethroid insecticide resistance threatens their ongoing effectiveness. In 2017, the WHO concluded that long-lasting ITNs (LLINs) with a synergist, piperonyl butoxide (PBO), provided additional public health benefit over conventional (pyrethroid-only) LLINs alone in areas of moderate insecticide resistance and endorsed them as a new class of vector control products. We performed an economic appraisal of PBO nets compared with conventional LLINs in 2019 US$ from prevention and health systems perspectives (including treatment cost offsets). We used data from a pragmatic randomized 2012–2014 trial in Nigeria with epidemiological outcomes in an area with confirmed pyrethroid resistance. Each village had 50 months of epidemiologic data, analyzed by village by month, using negative binomial regression. Compared with LLINs, although adding $0.90 per net delivered, PBO nets reduced symptomatic malaria cases by 33.4% (95% CI 10.2–50.6%). From a prevention perspective, the incremental cost-effectiveness ratio was $11 (95% CI $8–$37) per disability-adjusted life year averted. From the health systems perspective, PBO nets were significantly cost-saving relative to conventional LLINs. The benefit–cost analysis found that the added economic benefits of PBO nets over LLINs were $201 (95% CI $61–$304) for every $1 in incremental costs. Growing pyrethroid resistance is likely to strengthen the economic value of PBO nets over LLINs. Beyond their contribution to reducing malaria, PBO nets deliver outstanding economic returns for a small additional cost above conventional LLINs in locations with insecticide resistance.
Collapse
Affiliation(s)
- Donald S Shepard
- Heller School for Social Policy and Management, Brandeis University, Waltham, Massachusetts
| | - John U Odumah
- Heller School for Social Policy and Management, Brandeis University, Waltham, Massachusetts
| | - Samson T Awolola
- Molecular Entomology and Vector Control Research Laboratory, Nigerian Institute of Medical Research, Yaba Lagos, Nigeria
| |
Collapse
|
13
|
Hol FJH, Lambrechts L, Prakash M. BiteOscope, an open platform to study mosquito biting behavior. eLife 2020; 9:e56829. [PMID: 32960173 PMCID: PMC7535929 DOI: 10.7554/elife.56829] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 09/05/2020] [Indexed: 01/16/2023] Open
Abstract
Female mosquitoes need a blood meal to reproduce, and in obtaining this essential nutrient they transmit deadly pathogens. Although crucial for the spread of mosquito-borne diseases, blood feeding remains poorly understood due to technological limitations. Indeed, studies often expose human subjects to assess biting behavior. Here, we present the biteOscope, a device that attracts mosquitoes to a host mimic which they bite to obtain an artificial blood meal. The host mimic is transparent, allowing high-resolution imaging of the feeding mosquito. Using machine learning, we extract detailed behavioral statistics describing the locomotion, pose, biting, and feeding dynamics of Aedes aegypti, Aedes albopictus, Anopheles stephensi, and Anopheles coluzzii. In addition to characterizing behavioral patterns, we discover that the common insect repellent DEET repels Anopheles coluzzii upon contact with their legs. The biteOscope provides a new perspective on mosquito blood feeding, enabling the high-throughput quantitative characterization of this lethal behavior.
Collapse
Affiliation(s)
- Felix JH Hol
- Department of Bioengineering, Stanford UniversityStanfordUnited States
- Insect-Virus Interactions Unit, Institut Pasteur, UMR2000, CNRSParisFrance
- Center for research and Interdisciplinarity, U1284 INSERM, Université de ParisParisFrance
| | - Louis Lambrechts
- Insect-Virus Interactions Unit, Institut Pasteur, UMR2000, CNRSParisFrance
| | - Manu Prakash
- Department of Bioengineering, Stanford UniversityStanfordUnited States
| |
Collapse
|
14
|
Voloshin V, Kröner C, Seniya C, Murray GPD, Guy A, Towers CE, McCall PJ, Towers DP. Diffuse retro-reflective imaging for improved video tracking of mosquitoes at human baited bednets. ROYAL SOCIETY OPEN SCIENCE 2020; 7:191951. [PMID: 32537200 PMCID: PMC7277285 DOI: 10.1098/rsos.191951] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 04/06/2020] [Indexed: 05/09/2023]
Abstract
Robust imaging techniques for tracking insects have been essential tools in numerous laboratory and field studies on pests, beneficial insects and model systems. Recent innovations in optical imaging systems and associated signal processing have enabled detailed characterization of nocturnal mosquito behaviour around bednets and improvements in bednet design, a global essential for protecting populations against malaria. Nonetheless, there remain challenges around ease of use for large-scale in situ recordings and extracting data reliably in the critical areas of the bednet where the optical signal is attenuated. Here, we introduce a retro-reflective screen at the back of the measurement volume, which can simultaneously provide diffuse illumination, and remove optical alignment issues while requiring only one-sided access to the measurement space. The illumination becomes significantly more uniform, although noise removal algorithms are needed to reduce the effects of shot noise, particularly across low-intensity bednet regions. By systematically introducing mosquitoes in front of and behind the bednet in laboratory experiments, we are able to demonstrate robust tracking in these challenging areas. Overall, the retro-reflective imaging set-up delivers mosquito segmentation rates in excess of 90% compared to less than 70% with backlit systems.
Collapse
Affiliation(s)
- Vitaly Voloshin
- School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
| | - Christian Kröner
- School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
| | | | | | - Amy Guy
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | | | - Philip J. McCall
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - David P. Towers
- School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
| |
Collapse
|
15
|
Lines J. Malaria nets shape up for resistance. Nat Microbiol 2019; 5:6-7. [PMID: 31857730 DOI: 10.1038/s41564-019-0646-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jo Lines
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK.
| |
Collapse
|