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Wagman J, Chanda B, Chanda J, Saili K, Orange E, Mambo P, Muyabe R, Kaniki T, Mwenya M, Ng'andu M, Sakala J, Ngulube W, Miller J, Arnzen A, Silumbe K, Mwaanga G, Simubali L, Mungo A, Mburu MM, Simulundu E, Mambwe B, Kasaro R, Mulube C, Mwenda M, Hamainza B, Ashton RA, Eisele TP, Harris AF, Entwistle J, Yukich J, Slutsker L, Burkot TR, Littrell M. Entomological effects of attractive targeted sugar bait station deployment in Western Zambia: vector surveillance findings from a two-arm cluster randomized phase III trial. Malar J 2024; 23:214. [PMID: 39026236 PMCID: PMC11264679 DOI: 10.1186/s12936-024-05045-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Accepted: 07/16/2024] [Indexed: 07/20/2024] Open
Abstract
BACKGROUND Attractive targeted sugar bait (ATSB) stations are a novel tool with potential to complement current approaches to malaria vector control. To assess the public health value of ATSB station deployment in areas of high coverage with standard vector control, a two-arm cluster-randomized controlled trial (cRCT) of Sarabi ATSB® stations (Westham Ltd., Hod-Hasharon, Israel) was conducted in Western Province, Zambia, a high-burden location were Anopheles funestus is the dominant vector. The trial included 70 clusters and was designed to measure the effect of ATSBs on case incidence and infection prevalence over two 7-month deployments. Reported here are results of the vector surveillance component of the study, conducted in a subset of 20 clusters and designed to provide entomological context to guide overall interpretation of trial findings. METHODS Each month, 200 paired indoor-outdoor human landing catch (HLC) and 200 paired light trap (LT) collections were conducted to monitor An. funestus parity, abundance, biting rates, sporozoite prevalence, and entomological inoculation rates (EIR). RESULTS During the study 20,337 female An. funestus were collected, 11,229 from control and 9,108 from intervention clusters. A subset of 3,131 HLC specimens were assessed for parity: The mean non-parous proportion was 23.0% (95% CI 18.2-28.7%, total n = 1477) in the control and 21.2% (95% CI 18.8-23.9%, total n = 1654) in the intervention arm, an OR = 1.05 (95% CI 0.82-1.34; p = 0.688). A non-significant reduction in LT abundance (RR = 0.65 [95% CI 0.30-1.40, p = 0.267]) was associated with ATSB deployment. HLC rates were highly variable, but model results indicate a similar non-significant trend with a RR = 0.68 (95%CI 0.22-2.00; p = 0.479). There were no effects on sporozoite prevalence or EIR. CONCLUSIONS Anopheles funestus parity did not differ across study arms, but ATSB deployment was associated with a non-significant 35% reduction in vector LT density, results that are consistent with the epidemiological impact reported elsewhere. Additional research is needed to better understand how to maximize the potential impact of ATSB approaches in Zambia and other contexts. TRIAL REGISTRATION NUMBER This trial was registered with Clinicaltrials.gov (NCT04800055, 16 March 2021).
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Ruth A Ashton
- Centre for Applied Malaria Research and Evaluation, Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Thomas P Eisele
- Centre for Applied Malaria Research and Evaluation, Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | | | | | - Joshua Yukich
- Centre for Applied Malaria Research and Evaluation, Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | | | - Thomas R Burkot
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
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Orange E, Kyomuhangi I, Masuzyo M, Mwenya M, Mambo P, Saili K, Chishya C, Chanda J, Ashton RA, Eisele TP, Yukich J, Miller J, Silumbe K, Hamainza B, Wagman J, Arnzen A, Harris AF, Entwistle J, Slutsker L, Burkot TR, Littrell M. Deployment of attractive targeted sugar baits in western Zambia: installation, monitoring, removal, and disposal procedures during a Phase III cluster randomized controlled trial. Malar J 2024; 23:204. [PMID: 38982496 PMCID: PMC11234656 DOI: 10.1186/s12936-024-05030-w] [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: 04/05/2024] [Accepted: 06/28/2024] [Indexed: 07/11/2024] Open
Abstract
BACKGROUND Attractive Targeted Sugar Baits (ATSBs) offer a complementary vector control strategy to interventions targeting blood feeding or larval control by attacking the sugar feeding behaviour of adult mosquitoes using an attract-and-kill approach. Western Zambia was the first location to receive and deploy ATSB Sarabi version 1.2 stations in a Phase III cluster randomized controlled trial. This paper describes ATSB station installation, monitoring, removal, and disposal, quantifies ATSB station coverage, and reports major reasons for ATSB station replacement. METHODS ATSB stations were deployed during two annual transmission seasons, through scheduled installation and removal campaigns. During deployment, monitoring was conducted per protocol to maintain high coverage of the ATSB stations in good condition. Routine monitoring visits during the trial captured details on ATSB station damage necessitating replacement following pre-defined replacement criteria. Annual cross-sectional household surveys measured ATSB station coverage during peak malaria transmission. RESULTS A total of 67,945 ATSB stations were installed in Year 1 (41,695 initially installed+ 26,250 installed during monitoring) and 69,494 ATSB stations were installed in Year 2 (41,982 initially installed+ 27,512 installed during monitoring) across 35 intervention clusters to maintain high coverage of two ATSB stations in good condition per eligible household structure. The primary reasons for ATSB station replacement due to damage were holes/tears and presence of mold. Cross-sectional household surveys documented high coverage of ATSB stations across Year 1 and Year 2 with 93.1% of eligible structures having ≥ 2 ATSB stations in any condition. DISCUSSION ATSB station deployment and monitoring efforts were conducted in the context of a controlled cRCT to assess potential product efficacy. Damage to ATSB stations during deployment required replacement of a subset of stations. High coverage of eligible structures was maintained over the two-year study despite replacement requirements. Additional research is needed to better understand the impact of damage on ATSB station effectiveness under programmatic conditions, including thresholds of threats to physical integrity and biological deterioration on product efficacy. CONCLUSIONS Optimizing ATSB stations to address causes of damage and conducting implementation research to inform optimal delivery and cost-effective deployment will be important to facilitate scale-up of ATSB interventions.
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Affiliation(s)
| | - Irene Kyomuhangi
- Centre for Applied Malaria Research and Evaluation, Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA
- Centre for Health Informatics Computing and Statistics, Lancaster University, Lancaster, UK
| | | | | | | | | | | | | | - Ruth A Ashton
- Centre for Applied Malaria Research and Evaluation, Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Thomas P Eisele
- Centre for Applied Malaria Research and Evaluation, Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Joshua Yukich
- Centre for Applied Malaria Research and Evaluation, Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | | | | | | | | | | | | | | | | | - Thomas R Burkot
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Qld, Australia
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Mysore K, Njoroge TM, Stewart ATM, Winter N, Hamid-Adiamoh M, Sun L, Feng RS, James LD, Mohammed A, Severson DW, Duman-Scheel M. Characterization of a novel RNAi yeast insecticide that silences mosquito 5-HT1 receptor genes. Sci Rep 2023; 13:22511. [PMID: 38110471 PMCID: PMC10728091 DOI: 10.1038/s41598-023-49799-3] [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: 09/08/2023] [Accepted: 12/12/2023] [Indexed: 12/20/2023] Open
Abstract
G protein-coupled receptors (GPCRs), which regulate numerous intracellular signaling cascades that mediate many essential physiological processes, are attractive yet underexploited insecticide targets. RNA interference (RNAi) technology could facilitate the custom design of environmentally safe pesticides that target GPCRs in select target pests yet are not toxic to non-target species. This study investigates the hypothesis that an RNAi yeast insecticide designed to silence mosquito serotonin receptor 1 (5-HTR1) genes can kill mosquitoes without harming non-target arthropods. 5-HTR.426, a Saccharomyces cerevisiae strain that expresses an shRNA targeting a site specifically conserved in mosquito 5-HTR1 genes, was generated. The yeast can be heat-inactivated and delivered to mosquito larvae as ready-to-use tablets or to adult mosquitoes using attractive targeted sugar baits (ATSBs). The results of laboratory and outdoor semi-field trials demonstrated that consumption of 5-HTR.426 yeast results in highly significant mortality rates in Aedes, Anopheles, and Culex mosquito larvae and adults. Yeast consumption resulted in significant 5-HTR1 silencing and severe neural defects in the mosquito brain but was not found to be toxic to non-target arthropods. These results indicate that RNAi insecticide technology can facilitate selective targeting of GPCRs in intended pests without impacting GPCR activity in non-targeted organisms. In future studies, scaled production of yeast expressing the 5-HTR.426 RNAi insecticide could facilitate field trials to further evaluate this promising new mosquito control intervention.
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Affiliation(s)
- Keshava Mysore
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN, 46617, USA
- The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, USA
| | - Teresia M Njoroge
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN, 46617, USA
- The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, USA
| | - Akilah T M Stewart
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN, 46617, USA
- The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, USA
| | - Nikhella Winter
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, Trinidad and Tobago, Spain
| | - Majidah Hamid-Adiamoh
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN, 46617, USA
- The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, USA
| | - Longhua Sun
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN, 46617, USA
- The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, USA
| | - Rachel Shui Feng
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, Trinidad and Tobago, Spain
| | - Lester D James
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, Trinidad and Tobago, Spain
| | - Azad Mohammed
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, Trinidad and Tobago, Spain
| | - David W Severson
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN, 46617, USA
- The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, USA
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, Trinidad and Tobago, Spain
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, IN, USA
| | - Molly Duman-Scheel
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN, 46617, USA.
- The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, USA.
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, IN, USA.
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Yukich J, Eisele TP, terKuile F, Ashton R, Staedke S, Harris AF, Johnson PCD, Sarrassat S, Lesosky M, Bradley J, Kleinschmidt I, Littrell M. Master statistical analysis plan: attractive targeted sugar bait phase III trials in Kenya, Mali, and Zambia. Trials 2023; 24:771. [PMID: 38031086 PMCID: PMC10685482 DOI: 10.1186/s13063-023-07762-7] [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: 05/30/2023] [Accepted: 10/30/2023] [Indexed: 12/01/2023] Open
Abstract
This manuscript is a master statistical analysis plan for each of three-cluster randomized controlled trials to evaluate the efficacy of attractive targeted sugar baits (ATSB) described in an already published protocol. The master SAP contains an overarching plan for all three trials, which can be adapted to trial-specific circumstances. The primary objective of the trials is to evaluate the efficacy of ATSB in the presence of universal vector control coverage with insecticide-treated nets (ITN) or indoor residual spraying (IRS) after two transmission seasons on clinical malaria incidence as compared with universal vector control coverage with ITN or IRS alone. The primary outcome measure is the incidence rate of clinical malaria, assessed in cohorts aged 12 months to less than 15 years (≥ 5 years to 15 years in Mali) during monthly follow-up visits. The primary unadjusted analysis will be conducted on the intention-to-treat analysis population without adjustment for any anticipated confounding variables. The primary outcome will be analyzed using a multi-level model constructed on a generalized linear model framework with a Poisson likelihood and a log link function. Random intercepts will be included for each study cluster and a fixed effect for study-arm. The analyst will be blinded to study arm assignment. Several secondary outcomes will be analyzed, as well as a pooled analysis (individual patient data meta-analysis) across the three trial sites. Additionally, a standard meta-analysis is expected to be conducted using combined data from all sites.
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Affiliation(s)
- Joshua Yukich
- Tulane University School of Public Health and Tropical Medicine, New Orleans, USA.
| | - Thomas P Eisele
- Tulane University School of Public Health and Tropical Medicine, New Orleans, USA
| | - Feiko terKuile
- Tulane University School of Public Health and Tropical Medicine, New Orleans, USA
| | - Ruth Ashton
- Tulane University School of Public Health and Tropical Medicine, New Orleans, USA
| | - Sarah Staedke
- Tulane University School of Public Health and Tropical Medicine, New Orleans, USA
| | - Angela F Harris
- Tulane University School of Public Health and Tropical Medicine, New Orleans, USA
| | - Paul C D Johnson
- Tulane University School of Public Health and Tropical Medicine, New Orleans, USA
| | - Sophie Sarrassat
- Tulane University School of Public Health and Tropical Medicine, New Orleans, USA
| | - Maia Lesosky
- Tulane University School of Public Health and Tropical Medicine, New Orleans, USA
| | - John Bradley
- Tulane University School of Public Health and Tropical Medicine, New Orleans, USA
| | - Immo Kleinschmidt
- Tulane University School of Public Health and Tropical Medicine, New Orleans, USA
| | - Megan Littrell
- Tulane University School of Public Health and Tropical Medicine, New Orleans, USA
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Pullmann-Lindsley H, Bartlett-Miller A, Pitts RJ. Diols and sugar substitutes in attractive toxic sugar baits targeting Aedes aegypti and Aedes albopictus (Diptera: Culicidae) mosquitoes. JOURNAL OF MEDICAL ENTOMOLOGY 2023; 60:1022-1029. [PMID: 37348932 DOI: 10.1093/jme/tjad072] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 04/27/2023] [Accepted: 06/08/2023] [Indexed: 06/24/2023]
Abstract
Around the world, mosquitoes continue to transmit disease-causing pathogens and develop resistance to insecticides. We previously discovered that a generally regarded as safe (GRAS) compound, 1,2-propanediol, reduces adult mosquito survivorship when ingested. In this study, we assess and compare 5 more chemically related compounds for mosquito lethality and 8 GRAS sugar substitutes to determine toxicity. We conducted a series of feeding assays to determine if ingesting the compounds influenced mosquito mean survivorship in locally collected lab-reared populations of Aedes aegypti (Diptera, Culicidae, Linnaeus, 1762) and Aedes albopictus (Diptera, Culicidae, Skuse, 1894) mosquitoes. Our results indicate that 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,3-propanediol, DL-dithiothreitol, acesulfame potassium, allulose, erythritol, sodium saccharin, stevia, and sucralose significantly reduced the mean survivorship of one or both species. Short-term trials with the most toxic compounds revealed that they could substantially affect survivorship after 24 h. We also found that there were different responses in the 2 species and that in several experimental conditions, male mosquitoes expired to a greater extent than female mosquitoes. These findings indicate that several of the compounds are toxic to mosquitoes. Further study is required to determine their effectiveness in attractive toxic sugar baits (ATSBs) as a potential component of population control strategies.
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Affiliation(s)
| | - Ava Bartlett-Miller
- Department of Biology, Baylor University, 101 Bagby Avenue, Waco, TX 76706, USA
| | - Ronald Jason Pitts
- Department of Biology, Baylor University, 101 Bagby Avenue, Waco, TX 76706, USA
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Riske BF, Luckhart S, Riehle MA. Starving the Beast: Limiting Coenzyme A Biosynthesis to Prevent Disease and Transmission in Malaria. Int J Mol Sci 2023; 24:13915. [PMID: 37762222 PMCID: PMC10530615 DOI: 10.3390/ijms241813915] [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: 08/20/2023] [Revised: 09/07/2023] [Accepted: 09/08/2023] [Indexed: 09/29/2023] Open
Abstract
Malaria parasites must acquire all necessary nutrients from the vertebrate and mosquito hosts to successfully complete their life cycle. Failure to acquire these nutrients can limit or even block parasite development and presents a novel target for malaria control. One such essential nutrient is pantothenate, also known as vitamin B5, which the parasite cannot synthesize de novo and is required for the synthesis of coenzyme A (CoA) in the parasite. This review examines pantothenate and the CoA biosynthesis pathway in the human-mosquito-malaria parasite triad and explores possible approaches to leverage the CoA biosynthesis pathway to limit malaria parasite development in both human and mosquito hosts. This includes a discussion of sources for pantothenate for the mosquito, human, and parasite, examining the diverse strategies used by the parasite to acquire substrates for CoA synthesis across life stages and host resource pools and a discussion of drugs and alternative approaches being studied to disrupt CoA biosynthesis in the parasite. The latter includes antimalarial pantothenate analogs, known as pantothenamides, that have been developed to target this pathway during the human erythrocytic stages. In addition to these parasite-targeted drugs, we review studies of mosquito-targeted allosteric enzymatic regulators known as pantazines as an approach to limit pantothenate availability in the mosquito and subsequently deprive the parasite of this essential nutrient.
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Affiliation(s)
- Brendan F. Riske
- Department of Entomology, University of Arizona, Tucson, AZ 85721, USA;
| | - Shirley Luckhart
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843, USA;
- Department of Biological Sciences, University of Idaho, Moscow, ID 83843, USA
| | - Michael A. Riehle
- Department of Entomology, University of Arizona, Tucson, AZ 85721, USA;
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Njoroge TM, Hamid-Adiamoh M, Duman-Scheel M. Maximizing the Potential of Attractive Targeted Sugar Baits (ATSBs) for Integrated Vector Management. INSECTS 2023; 14:585. [PMID: 37504591 PMCID: PMC10380652 DOI: 10.3390/insects14070585] [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: 05/18/2023] [Revised: 06/23/2023] [Accepted: 06/24/2023] [Indexed: 07/29/2023]
Abstract
Due to the limitations of the human therapeutics and vaccines available to treat and prevent mosquito-borne diseases, the primary strategy for disease mitigation is through vector control. However, the current tools and approaches used for mosquito control have proven insufficient to prevent malaria and arboviral infections, such as dengue, Zika, and lymphatic filariasis, and hence, these diseases remain a global public health threat. The proven ability of mosquito vectors to adapt to various control strategies through insecticide resistance, invasive potential, and behavioral changes from indoor to outdoor biting, combined with human failures to comply with vector control requirements, challenge sustained malaria and arboviral disease control worldwide. To address these concerns, increased efforts to explore more varied and integrated control strategies have emerged. These include approaches that involve the behavioral management of vectors. Attractive targeted sugar baits (ATSBs) are a vector control approach that manipulates and exploits mosquito sugar-feeding behavior to deploy insecticides. Although traditional approaches have been effective in controlling malaria vectors indoors, preventing mosquito bites outdoors and around human dwellings is challenging. ATSBs, which can be used to curb outdoor biting mosquitoes, have the potential to reduce mosquito densities and clinical malaria incidence when used in conjunction with existing vector control strategies. This review examines the available literature regarding the utility of ATSBs for mosquito control, providing an overview of ATSB active ingredients (toxicants), attractants, modes of deployment, target organisms, and the potential for integrating ATSBs with existing vector control interventions.
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Affiliation(s)
- Teresia Muthoni Njoroge
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, South Bend, IN 46556, USA
| | - Majidah Hamid-Adiamoh
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, South Bend, IN 46556, USA
| | - Molly Duman-Scheel
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, South Bend, IN 46556, USA
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Muyaga LL, Meza FC, Kahamba NF, Njalambaha RM, Msugupakulya BJ, Kaindoa EW, Ngowo HS, Okumu FO. Effects of vegetation densities on the performance of attractive targeted sugar baits (ATSBs) for malaria vector control: a semi-field study. Malar J 2023; 22:190. [PMID: 37344867 DOI: 10.1186/s12936-023-04625-z] [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: 09/05/2022] [Accepted: 06/16/2023] [Indexed: 06/23/2023] Open
Abstract
BACKGROUND Attractive targeted sugar baits (ATSBs) control sugar-feeding mosquitoes with oral toxicants, and may effectively complement core malaria interventions, such as insecticide-treated nets even where pyrethroid-resistance is widespread. The technology is particularly efficacious in arid and semi-arid areas. However, their performance remains poorly-understood in tropical areas with year-round malaria transmission, and where the abundant vegetation constitutes competitive sugar sources for mosquitoes. This study compared the efficacies of ATSBs (active ingredient: 2% boric acid) in controlled settings with different vegetation densities. METHODS Potted mosquito-friendly plants were introduced inside semi-field chambers (9.6 m by 9.6 m) to simulate densely-vegetated, sparsely-vegetated, and bare sites without any vegetation (two chambers/category). All chambers had volunteer-occupied huts. Laboratory-reared Anopheles arabiensis were released nightly (200/chamber) and host-seeking females recaptured using human landing catches outdoors (8.00 p.m.-9.00 p.m.) and CDC-light traps indoors (9.00 p.m.-6.00 a.m.). Additionally, resting mosquitoes were collected indoors and outdoors each morning using Prokopack aspirators. The experiments included a "before-and-after" set-up (with pre-ATSBs, ATSBs and post-ATSBs phases per chamber), and a "treatment vs. control" set-up (where similar chambers had ATSBs or no ATSBs). The experiments lasted 84 trap-nights. RESULTS In the initial tests when all chambers had no vegetation, the ATSBs reduced outdoor-biting by 69.7%, indoor-biting by 79.8% and resting mosquitoes by 92.8%. In tests evaluating impact of vegetation, the efficacy of ATSBs against host-seeking mosquitoes was high in bare chambers (outdoors: 64.1% reduction; indoors: 46.8%) but modest or low in sparsely-vegetated (outdoors: 34.5%; indoors: 26.2%) and densely-vegetated chambers (outdoors: 25.4%; indoors: 16.1%). Against resting mosquitoes, the ATSBs performed modestly across settings (non-vegetated chambers: 37.5% outdoors and 38.7% indoors; sparsely-vegetated: 42.9% outdoors and 37.5% indoors; densely-vegetated: 45.5% outdoors and 37.5% indoors). Vegetation significantly reduced the ATSBs efficacies against outdoor-biting and indoor-biting mosquitoes but not resting mosquitoes. CONCLUSION While vegetation can influence the performance of ATSBs, the devices remain modestly efficacious in both sparsely-vegetated and densely-vegetated settings. Higher efficacies may occur in places with minimal or completely no vegetation, but such environments are naturally unlikely to sustain Anopheles populations or malaria transmission in the first place. Field studies therefore remain necessary to validate the efficacies of ATSBs in the tropics.
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Affiliation(s)
- Letus L Muyaga
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania.
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK.
| | - Felician C Meza
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
| | - Najat F Kahamba
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Rukiyah M Njalambaha
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
| | - Betwel J Msugupakulya
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Emmanuel W Kaindoa
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- School of Life Sciences and Biotechnology, Nelson Mandela African Institution of Science and Technology, Arusha, United Republic of Tanzania
- Faculty of Health Sciences, School of Pathology, Centre for Emerging Zoonotic and Parasitic Diseases, Wits Research Institute for Malaria, University of the Witwatersrand, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Halfan S Ngowo
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Fredros O Okumu
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania.
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK.
- School of Life Sciences and Biotechnology, Nelson Mandela African Institution of Science and Technology, Arusha, United Republic of Tanzania.
- School of Public Health, University of the Witwatersrand, Johannesburg, South Africa.
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Chanda J, Wagman J, Chanda B, Kaniki T, Ng’andu M, Muyabe R, Mwenya M, Sakala J, Miller J, Mwaanga G, Simubali L, Mburu MM, Simulundu E, Mungo A, Fraser K, Mwandigha L, Ashton R, Yukich J, Harris AF, Burkot TR, Orange E, Littrell M, Entwistle J. Feeding rates of malaria vectors from a prototype attractive sugar bait station in Western Province, Zambia: results of an entomological validation study. Malar J 2023; 22:70. [PMID: 36855105 PMCID: PMC9974387 DOI: 10.1186/s12936-023-04491-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 02/13/2023] [Indexed: 03/02/2023] Open
Abstract
BACKGROUND Attractive targeted sugar bait (ATSB) stations are a promising new approach to malaria vector control that could compliment current tools by exploiting the natural sugar feeding behaviors of mosquitoes. Recent proof of concept work with a prototype ATSB® Sarabi Bait Station (Westham Co., Hod-Hasharon, Israel) has demonstrated high feeding rates and significant reductions in vector density, human biting rate, and overall entomological inoculation rate for Anopheles gambiae sensu lato (s.l.) in the tropical savannah of western Mali. The study reported here was conducted in the more temperate, rainier region of Western Province, Zambia and was designed to confirm the primary vector species in region and to estimate corresponding rates of feeding from prototype attractive sugar bait (ASB) Sarabi Bait Stations. METHODS The product evaluated was the Sarabi v1.1.1 ASB station, which did not include insecticide but did include 0.8% uranine as a dye allowing for the detection, using UV fluorescence light microscopy, of mosquitoes that have acquired a sugar meal from the ASB. A two-phase, crossover study design was conducted in 10 village-based clusters in Western Province, Zambia. One study arm initially received 2 ASB stations per eligible structure while the other initially received 3. Primary mosquito sampling occurred via indoor and outdoor CDC Miniature UV Light Trap collection from March 01 through April 09, 2021 (Phase 1) and from April 19 to May 28, 2021 (Phase 2). RESULTS The dominant vector in the study area is Anopheles funestus s.l., which was the most abundant species group collected (31% of all Anophelines; 45,038/144,5550), had the highest sporozoite rate (3.16%; 66 positives out of 2,090 tested), and accounted for 94.3% (66/70) of all sporozoite positive specimens. Of those An. funestus specimens further identified to species, 97.2% (2,090/2,150) were An. funestus sensu stricto (s.s.). Anopheles gambiae s.l. (96.8% of which were Anopheles arabiensis) is a likely secondary vector and Anopheles squamosus may play a minor role in transmission. Overall, 21.6% (9,218/42,587) of An. funestus specimens and 10.4% (201/1,940) of An. gambiae specimens collected were positive for uranine, translating into an estimated daily feeding rate of 8.9% [7.7-9.9%] for An. funestus (inter-cluster range of 5.5% to 12.7%) and 3.9% [3.3-4.7%] for An. gambiae (inter-cluster range of 1.0-5.2%). Feeding rates were no different among mosquitoes collected indoors or outdoors, or among mosquitoes from clusters with 2 or 3 ASBs per eligible structure. Similarly, there were no correlations observed between feeding rates and the average number of ASB stations per hectare or with weekly rainfall amounts. CONCLUSIONS Anopheles funestus and An. gambiae vector populations in Western Province, Zambia readily fed from the prototype Sarabi v1.1.1 ASB sugar bait station. Observed feeding rates are in line with those thought to be required for ATSB stations to achieve reductions in malaria transmission when used in combination with conventional control methods (IRS or LLIN). These results supported the decision to implement a large-scale, epidemiological cluster randomized controlled trial of ATSB in Zambia, deploying 2 ATSB stations per eligible structure.
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Affiliation(s)
| | | | | | | | | | | | | | - Jimmy Sakala
- PATH, Lusaka, Zambia ,Present Address: Jhpeigo, Lusaka, Zambia
| | | | | | | | | | | | | | - Keith Fraser
- grid.7445.20000 0001 2113 8111Imperial College London, London, UK
| | - Lazaro Mwandigha
- grid.7445.20000 0001 2113 8111Imperial College London, London, UK ,grid.4991.50000 0004 1936 8948Present Address: University of Oxford, Oxford, UK
| | - Ruth Ashton
- grid.265219.b0000 0001 2217 8588School of Public Health and Tropical Medicine, Tulane University, New Orleans, USA
| | - Joshua Yukich
- grid.265219.b0000 0001 2217 8588School of Public Health and Tropical Medicine, Tulane University, New Orleans, USA
| | | | - Thomas R. Burkot
- grid.1011.10000 0004 0474 1797Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - Erica Orange
- grid.415269.d0000 0000 8940 7771PATH, Seattle, USA
| | - Megan Littrell
- grid.416809.20000 0004 0423 0663PATH, Washington, DC USA
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Doumbia S, Toure M, Sogoba N, Alifrangis M, Diakite M, Diarra A, Keita M, Konaté D, Diawara SI, Thiam SM, Keita S, Tounkara M, Cissé I, Sanogo V, Magassa MH, Barry AE, Winch PJ, Marker HC, Shaffer JG, Traoré SF, Müller GC, Cui L, Beier JC, Mihigo J. The West Africa ICEMR Partnerships for Guiding Policy to Improve the Malaria Prevention and Control. Am J Trop Med Hyg 2022; 107:84-89. [PMID: 36228908 PMCID: PMC9662222 DOI: 10.4269/ajtmh.21-1330] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 07/06/2022] [Indexed: 12/01/2022] Open
Abstract
The Mali National Malaria Control Program (NMCP) recently established a phased set of goals for eliminating malaria in Mali by 2030. Over the past decade, the scale-up of NMCP-led malaria control interventions has led to considerable progress, as evidenced by multiple malariometric indicators. The West Africa International Center of Excellence in Malaria Research (WA-ICEMR) is a multidisciplinary research program that works closely with the NMCP and its partners to address critical research needs for malaria control. This coordinated effort includes assessing the effectiveness of control interventions based on key malaria research topics, including immune status, parasite genetic diversity, insecticide and drug resistance, diagnostic accuracy, malaria vector populations and biting behaviors, and vectorial capacity. Several signature accomplishments of the WA-ICEMR include identifying changing malaria age demographic profiles, testing innovative approaches to improve control strategies, and providing regular reporting on drug and insecticide resistance status. The NMCP and WA-ICEMR partnership between the WA-ICEMR and the NMCP offers a comprehensive research platform that informs the design and implementation of malaria prevention and control research programs. These efforts build local expertise and capacity for the next generation of malaria researchers and guide local policy, which is crucial in sustaining efforts toward eliminating malaria in West Africa.
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Affiliation(s)
- Seydou Doumbia
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Mahamoudou Toure
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Nafomon Sogoba
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Michael Alifrangis
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark; Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Mahamadou Diakite
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Ayouba Diarra
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Moussa Keita
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Drissa Konaté
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sory I. Diawara
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sidibé M’Baye Thiam
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Soumba Keita
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Moctar Tounkara
- Department of Public Health, Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Idrissa Cissé
- National Malaria Control Program, Ministry of Health, Bamako, Mali
| | - Vincent Sanogo
- National Malaria Control Program, Ministry of Health, Bamako, Mali
| | | | | | - Peter J. Winch
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Hannah C. Marker
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Jeffrey G. Shaffer
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana
| | - Sékou F. Traoré
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Günter C. Müller
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Liwang Cui
- Division of Infectious Diseases and Internal Medicine, Department of Internal Medicine, University of South Florida, Tampa, Florida
| | - John C. Beier
- Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, Florida
| | - Jules Mihigo
- U.S. President’s Malaria Initiative, United States Agency for International Development Office, Bamako, Mali
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Doumbia S, Sogoba N, Diakite M, Toure M, Keita M, Konaté D, Diawara SI, Diarra A, Sanogo D, Kane F, Diakite SAS, Traore K, Thiam SM, Traoré SF, Cisse I, Mihigo J, Coulibaly MB, Dabitao D, Alifrangis M, Barry AE, Müller GC, Beier JC, Shaffer JG. A Decade of Progress Accelerating Malaria Control in Mali: Evidence from the West Africa International Center of Excellence for Malaria Research. Am J Trop Med Hyg 2022; 107:75-83. [PMID: 36228923 PMCID: PMC9662231 DOI: 10.4269/ajtmh.21-1309] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 07/06/2022] [Indexed: 11/07/2022] Open
Abstract
This article highlights over a decade of signature achievements by the West Africa International Centers for Excellence in Malaria Research (WA-ICEMR) and its partners toward guiding malaria prevention and control strategies. Since 2010, the WA-ICEMR has performed longitudinal studies to monitor and assess malaria control interventions with respect to space-time patterns, vector transmission indicators, and drug resistance markers. These activities were facilitated and supported by the Mali National Malaria Control Program. Research activities included large-scale active and passive surveillance and expanded coverage of universal long-lasting insecticide-treated bed nets and seasonal malaria chemoprevention (SMC). The findings revealed substantial declines in malaria occurrence after the scale-up of control interventions in WA-ICEMR study sites. WA-ICEMR studies showed that SMC using sulfadoxine-pyrimethamine plus amodiaquine was highly effective in preventing malaria among children under 5 years of age. An alternative SMC regimen (dihydroartemisinin plus piperaquine) was shown to be potentially more effective and provided advantages for acceptability and compliance over the standard SMC regimen. Other findings discussed in this article include higher observed multiplicity of infection rates for malaria in historically high-endemic areas, continued antimalarial drug sensitivity to Plasmodium falciparum, high outdoor malaria transmission rates, and increased insecticide resistance over the past decade. The progress achieved by the WA-ICEMR and its partners highlights the critical need for maintaining current malaria control interventions while developing novel strategies to disrupt malaria transmission. Enhanced evaluation of these strategies through research partnerships is particularly needed in the wake of reported artemisinin resistance in Southeast Asia and East Africa.
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Affiliation(s)
- Seydou Doumbia
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Nafomon Sogoba
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Mahamadou Diakite
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Mahamoudou Toure
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Moussa Keita
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Drissa Konaté
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sory I. Diawara
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Ayouba Diarra
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Daouda Sanogo
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Fousseyni Kane
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Seidina A. S. Diakite
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Karim Traore
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sidibé M’Baye Thiam
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sékou F. Traoré
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Idrissa Cisse
- National Malaria Control Program, Ministry of Health, Bamako, Mali
| | - Jules Mihigo
- U.S. President’s Malaria Initiative, United States Agency for International Development Office, Bamako, Mali
| | - Mamadou B. Coulibaly
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Djeneba Dabitao
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Michael Alifrangis
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark; Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | | | - Günter C. Müller
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
- University Clinical Research Center, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - John C. Beier
- Miller School of Medicine, University of Miami, Miami, Florida
| | - Jeffrey G. Shaffer
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana
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An efficient and biodegradable alginate-gelatin hydrogel beads as bait against Aedes aegypti and Aedes albopictus. Int J Biol Macromol 2022; 224:1460-1470. [DOI: 10.1016/j.ijbiomac.2022.10.233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 10/17/2022] [Accepted: 10/25/2022] [Indexed: 11/05/2022]
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Eisele TP, Kleinschmidt I, Sarrassat S, terKuile F, Miller J, Chanda J, Silumbe K, Samuels A, Janssen J, Ogwang C, Bradley J, Orange E, Yukich J, Ashton R, Kyomuhangi I, Harris AF, Doumbia S, Toure M, Moumine M, Majambere S, Mburu MM, Mwaanga G, Simubali L, Simulundu E, Bennett A, Slutsker L, Muller G, Ochomo E, Gimnig J, Johnson PCD, Wagman J, Littrell M. Attractive targeted sugar bait phase III trials in Kenya, Mali, and Zambia. Trials 2022; 23:640. [PMID: 35945599 PMCID: PMC9361277 DOI: 10.1186/s13063-022-06555-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 07/16/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) target night-time indoor biting mosquitoes and effectively reduce malaria transmission in rural settings across Africa, but additional vector control tools are needed to interrupt transmission. Attractive targeted sugar baits (ATSBs) attract and kill mosquitoes, including those biting outdoors. Deployment of ATSBs incorporating the insecticide dinotefuran was associated with major reductions in mosquito density and longevity in Mali. The impact of this promising intervention on malaria transmission and morbidity now needs to be determined in a range of transmission settings. METHODS/DESIGN We will conduct three similar stand-alone, open-label, two-arm, cluster-randomized, controlled trials (cRCTs) in Mali, Kenya, and Zambia to determine the impact of ATSB + universal vector control versus universal vector control alone on clinical malaria. The trials will use a "fried-egg" design, with primary outcomes measured in the core area of each cluster to reduce spill-over effects. All household structures in the ATSB clusters will receive two ATSBs, but the impact will be measured in the core of clusters. Restricted randomization will be used. The primary outcome is clinical malaria incidence among children aged 5-14 years in Mali and 1-14 years in Kenya and Zambia. A key secondary outcome is malaria parasite prevalence across all ages. The trials will include 76 clusters (38 per arm) in Mali and 70 (35 per arm) in each of Kenya and Zambia. The trials are powered to detect a 30% reduction in clinical malaria, requiring a total of 3850 person-years of follow-up in Mali, 1260 person-years in Kenya, and 1610 person-years in Zambia. These sample sizes will be ascertained using two seasonal 8-month cohorts in Mali and two 6-month seasonal cohorts in Zambia. In Kenya, which has year-round transmission, four 6-month cohorts will be used (total 24 months of follow-up). The design allows for one interim analysis in Mali and Zambia and two in Kenya. DISCUSSION Strengths of the design include the use of multiple study sites with different transmission patterns and a range of vectors to improve external validity, a large number of clusters within each trial site, restricted randomization, between-cluster separation to minimize contamination between study arms, and an adaptive trial design. Noted threats to internal validity include open-label design, risk of contamination between study arms, risk of imbalance of covariates across study arms, variation in durability of ATSB stations, and potential disruption resulting from the COVID-19 pandemic. TRIAL REGISTRATION Zambia: ClinicalTrials.gov NCT04800055 . Registered on March 15, 2021 Mali: ClinicalTrials.gov NCT04149119 . Registered on November 4, 2019 Kenya: ClinicalTrials.gov NCT05219565 . Registered on February 2, 2022.
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Ferreira TN, Brazil RP, McDowell MA, Cunha-Júnior EF, Costa PRR, Netto CD, Santos ECT, Genta FA. Effects of anti-Leishmania compounds in the behavior of the sand fly vector Lutzomyia longipalpis. PEST MANAGEMENT SCIENCE 2022; 78:2792-2805. [PMID: 35411662 DOI: 10.1002/ps.6900] [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: 10/14/2021] [Revised: 03/25/2022] [Accepted: 04/12/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Leishmaniasis is an infectious parasitic disease caused by pathogens of the genus Leishmania transmitted through the bite of adult female sand flies. To reduce case numbers, it is necessary to combine different control approaches, especially those aimed at the sand fly vectors. Innovative forms of control with the use of attractive sugar baits explored the fact that adult sand flies need to feed on sugars of plant origin. Leishmania parasites develop in the gut of sand flies, interacting with the sugars in the diet of adults. Recent studies have shown that sugar baits containing plant-derived compounds can reduce sand fly survival, the number of parasites per gut, and the percentage of infected sand flies. Several synthetic compounds produced from naphthoquinones and pterocarpans have anti-parasitic activity on Leishmania amazonensis and/or Leishmania infantum in cell culture. This work aimed to assess the inclusion of these compounds in sugar baits for blocking transmission, targeting the development of the Leishmania parasite inside the sand fly vector. RESULTS We evaluated the attractant or repellent properties of these compounds, as well as of the reference compound N,N'-diethyl-m-toluamide (DEET), in sugar baits. We also observed changes in feeding preference caused by these compounds, looking for anti-feeding or stimulation of ingestion. Pterocarpanquinone L4 and pentamidine showed attractant and repellent properties, respectively. CONCLUSION Based on the effects in feeding preference and intake volume, pterocarpanquinone L6, and the pyrazole-derived compound P8 were chosen as the most promising compounds for the future development of anti-Leishmania sugar baits. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- Tainá Neves Ferreira
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - Reginaldo Peçanha Brazil
- Laboratório de Doenças Parasitárias, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, Brazil
| | - Mary Ann McDowell
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Edézio Ferreira Cunha-Júnior
- Laboratório de Imunoparasitologia, Unidade Integrada de Pesquisa em Produtos Bioativos e Biociências, Universidade Federal do Rio de Janeiro, Campus UFRJ-Macaé, Macaé, Brazil
| | - Paulo Roberto Ribeiro Costa
- Laboratório de Química Bioorgânica, Instituto de Pesquisas de Produtos Naturais, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Chaquip Daher Netto
- Laboratório de Química, Universidade Federal do Rio de Janeiro, Macaé, Brazil
| | - Eduardo Caio Torres Santos
- Laboratório de Bioquímica de Tripanossomatídeos, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - Fernando Ariel Genta
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, Brazil
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Mysore K, Sun L, Hapairai LK, Wang CW, Igiede J, Roethele JB, Scheel ND, Scheel MP, Li P, Wei N, Severson DW, Duman-Scheel M. A Yeast RNA-Interference Pesticide Targeting the Irx Gene Functions as a Broad-Based Mosquito Larvicide and Adulticide. INSECTS 2021; 12:insects12110986. [PMID: 34821787 PMCID: PMC8622680 DOI: 10.3390/insects12110986] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 10/28/2021] [Accepted: 10/28/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary It is critical that we identify new methods of preventing mosquito-borne infectious diseases, which threaten millions of people worldwide. In this investigation, we describe characterization of a new insecticide that turns off the mosquito Iroquois (Irx) gene, which is required for mosquito survival. The pesticide is synthesized in yeast, which can be fed to adult mosquitoes in a sugar bait solution or to juvenile mosquitoes that eat the yeast when it is placed in water where mosquitoes breed. Although the yeast kills several different types of mosquitoes, it was not found to affect the survival of other types of arthropods that consumed the yeast. These results indicate that yeast insecticides could one day be used for environmentally friendly mosquito control and disease prevention. Abstract Concerns for widespread insecticide resistance and the unintended impacts of insecticides on nontarget organisms have generated a pressing need for mosquito control innovations. A yeast RNAi-based insecticide that targets a conserved site in mosquito Irx family genes, but which has not yet been identified in the genomes of nontarget organisms, was developed and characterized. Saccharomyces cerevisiae constructed to express short hairpin RNA (shRNA) matching the target site induced significant Aedes aegypti larval death in both lab trials and outdoor semi-field evaluations. The yeast also induced high levels of mortality in adult females, which readily consumed yeast incorporated into an attractive targeted sugar bait (ATSB) during simulated field trials. A conserved requirement for Irx function as a regulator of proneural gene expression was observed in the mosquito brain, suggesting a possible mode of action. The larvicidal and adulticidal properties of the yeast were also verified in Aedes albopictus, Anopheles gambiae, and Culexquinquefasciatus mosquitoes, but the yeast larvicide was not toxic to other nontarget arthropods. These results indicate that further development and evaluation of this technology as an ecofriendly control intervention is warranted, and that ATSBs, an emerging mosquito control paradigm, could potentially be enriched through the use of yeast-based RNAi technology.
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Affiliation(s)
- Keshava Mysore
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA; (K.M.); (L.S.); (L.K.H.); (J.B.R.); (M.P.S.); (P.L.); (D.W.S.)
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA; (C.-W.W.); (J.I.); (N.D.S.); (N.W.)
| | - Longhua Sun
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA; (K.M.); (L.S.); (L.K.H.); (J.B.R.); (M.P.S.); (P.L.); (D.W.S.)
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA; (C.-W.W.); (J.I.); (N.D.S.); (N.W.)
| | - Limb K. Hapairai
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA; (K.M.); (L.S.); (L.K.H.); (J.B.R.); (M.P.S.); (P.L.); (D.W.S.)
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA; (C.-W.W.); (J.I.); (N.D.S.); (N.W.)
| | - Chien-Wei Wang
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA; (C.-W.W.); (J.I.); (N.D.S.); (N.W.)
- Department of Civil and Environmental Engineering and Earth Sciences, The University of Notre Dame, Notre Dame, IN 46556, USA
| | - Jessica Igiede
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA; (C.-W.W.); (J.I.); (N.D.S.); (N.W.)
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, IN 46556, USA
| | - Joseph B. Roethele
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA; (K.M.); (L.S.); (L.K.H.); (J.B.R.); (M.P.S.); (P.L.); (D.W.S.)
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA; (C.-W.W.); (J.I.); (N.D.S.); (N.W.)
| | - Nicholas D. Scheel
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA; (C.-W.W.); (J.I.); (N.D.S.); (N.W.)
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, IN 46556, USA
| | - Max P. Scheel
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA; (K.M.); (L.S.); (L.K.H.); (J.B.R.); (M.P.S.); (P.L.); (D.W.S.)
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA; (C.-W.W.); (J.I.); (N.D.S.); (N.W.)
| | - Ping Li
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA; (K.M.); (L.S.); (L.K.H.); (J.B.R.); (M.P.S.); (P.L.); (D.W.S.)
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA; (C.-W.W.); (J.I.); (N.D.S.); (N.W.)
| | - Na Wei
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA; (C.-W.W.); (J.I.); (N.D.S.); (N.W.)
- Department of Civil and Environmental Engineering and Earth Sciences, The University of Notre Dame, Notre Dame, IN 46556, USA
| | - David W. Severson
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA; (K.M.); (L.S.); (L.K.H.); (J.B.R.); (M.P.S.); (P.L.); (D.W.S.)
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA; (C.-W.W.); (J.I.); (N.D.S.); (N.W.)
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, IN 46556, USA
- Department of Life Sciences, The University of the West Indies, St. Augustine, Trinidad, Trinidad and Tobago
| | - Molly Duman-Scheel
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA; (K.M.); (L.S.); (L.K.H.); (J.B.R.); (M.P.S.); (P.L.); (D.W.S.)
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA; (C.-W.W.); (J.I.); (N.D.S.); (N.W.)
- Correspondence:
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16
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Stromsky VE, Hajkazemian M, Vaisbourd E, Mozūraitis R, Noushin Emami S. Plasmodium metabolite HMBPP stimulates feeding of main mosquito vectors on blood and artificial toxic sources. Commun Biol 2021; 4:1161. [PMID: 34620990 PMCID: PMC8497504 DOI: 10.1038/s42003-021-02689-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 09/16/2021] [Indexed: 02/08/2023] Open
Abstract
Recent data show that parasites manipulate the physiology of mosquitoes and human hosts to increase the probability of transmission. Here, we investigate phagostimulant activity of Plasmodium-metabolite, (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), in the primary vectors of multiple human diseases, Anopheles coluzzii, An. arabiensis, An. gambiae s.s., Aedes aegypti, and Culex pipiens/Culex torrentium complex species. The addition of 10 µM HMBPP to blood meals significantly increased feeding in all the species investigated. Moreover, HMBPP also exhibited a phagostimulant property in plant-based-artificial-feeding-solution made of beetroot juice adjusted to neutral pH similar to that of blood. The addition of AlbuMAXTM as a lipid/protein source significantly improved the feeding rate of An. gambiae s.l. females providing optimised plant-based-artificial-feeding-solution for delivery toxins to control vector populations. Among natural and synthetic toxins tested, only fipronil sulfone did not reduce feeding. Overall, the toxic-plant-based-artificial-feeding-solution showed potential as an effector in environmentally friendly vector-control strategies.
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Affiliation(s)
- Viktoria E Stromsky
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Melika Hajkazemian
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Elizabeth Vaisbourd
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Raimondas Mozūraitis
- Laboratory of Chemical and Behavioural Ecology, Institute of Ecology, Nature Research Centre, Vilnius, Lithuania
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - S Noushin Emami
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.
- Molecular Attraction AB, Elektravägen 10, 126 30 Hägersten, Stockholm, Sweden.
- Natural Resources Institute, FES, University of Greenwich, London, UK.
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17
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A Broad-Based Mosquito Yeast Interfering RNA Pesticide Targeting Rbfox1 Represses Notch Signaling and Kills Both Larvae and Adult Mosquitoes. Pathogens 2021; 10:pathogens10101251. [PMID: 34684200 PMCID: PMC8541554 DOI: 10.3390/pathogens10101251] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 12/03/2022] Open
Abstract
Prevention of mosquito-borne infectious diseases will require new classes of environmentally safe insecticides and novel mosquito control technologies. Saccharomyces cerevisiae was engineered to express short hairpin RNA (shRNA) corresponding to mosquito Rbfox1 genes. The yeast induced target gene silencing, resulting in larval death that was observed in both laboratory and outdoor semi-field trials conducted on Aedes aegypti. High levels of mortality were also observed during simulated field trials in which adult females consumed yeast delivered through a sugar bait. Mortality correlated with defects in the mosquito brain, in which a role for Rbfox1 as a positive regulator of Notch signaling was identified. The larvicidal and adulticidal activities of the yeast were subsequently confirmed in trials conducted on Aedes albopictus, Anopheles gambiae, and Culex quinquefasciatus, yet the yeast had no impact on survival of select non-target arthropods. These studies indicate that yeast RNAi pesticides targeting Rbfox1 could be further developed as broad-based mosquito larvicides and adulticides for deployment in integrated biorational mosquito control programs. These findings also suggest that the species-specificity of attractive targeted sugar baits, a new paradigm for vector control, could potentially be enhanced through RNAi technology, and specifically through the use of yeast-based interfering RNA pesticides.
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