1
|
Sforzín A, Lucia A, Alzogaray RA. Two Lactones Non-toxic to Humans Are Effective Repellents for the German Cockroach. NEOTROPICAL ENTOMOLOGY 2024; 53:694-700. [PMID: 38478302 DOI: 10.1007/s13744-024-01139-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 02/09/2024] [Indexed: 05/07/2024]
Abstract
Lactones are cyclic esters of hydroxy carboxylic acids, present in several fruits and animals consumed by humans. There is evidence that some lactones modify insect behavior. The aim of the present study was to evaluate the repellent effect of four lactones (γ- and δ-nonalactone, and γ- and δ-dodecalactone) in first instar nymphs of the German cockroach, Blattella germanica (Linnaeus). To assess repellency, a nymph was placed on a circle of filter paper, half of which had been treated with lactone dissolved in acetone and the other half with acetone alone. The behavior of the nymph was recorded and the time the nymph spent in each half of the paper was quantified using Ethovision XT 10.1 software. Values of Distribution Coefficient (DC) were calculated: DC = (Tt - TA) / Tt, where Tt is the experimental time and TA is the time the nymph spent in the area treated with the repellent agent. DC can vary between 0 and 1. Values significantly higher than 0.5 indicate repellency. N,N-diethyl-meta-toluamide (DEET) was used as a positive control. DEET, δ- and γ-nonalactone caused repellency as from 77.9 µg/cm2, whereas γ- and δ-dodecalactone had a repellent effect starting at 779.0 µg/cm2. The values of DC for these concentrations were 0.89 (DEET), 0.86 (γ-nonalactone), 0.87 (δ-nonalactone), 0.83 (γ-dodecalactone), and 0.72 (δ-dodecalactone). To our knowledge, this is the first report of repellency produced by lactones in the German cockroach. This work allowed to identify two lactones that have a repellent effect similar to DEET.
Collapse
Affiliation(s)
- Analía Sforzín
- Centro de Investigaciones de Plagas e Insecticidas (UNIDEF-CITEDEF-CONICET-CIPEIN), Villa Martelli, Buenos Aires, Argentina. analia-s-@hotmail.com
| | - Alejandro Lucia
- Instituto de Ecología y Desarrollo Sustentable (INEDES), Luján, Buenos Aires, Argentina
| | - Raúl A Alzogaray
- Centro de Investigaciones de Plagas e Insecticidas (UNIDEF-CITEDEF-CONICET-CIPEIN), Villa Martelli, Buenos Aires, Argentina
- Escuela de Hábitat y Sostenibilidad (EHyS), Univ Nacional de San Martín, San Martín, Buenos Aires, Argentina
| |
Collapse
|
2
|
Torto B, Tchouassi DP. Chemical Ecology and Management of Dengue Vectors. ANNUAL REVIEW OF ENTOMOLOGY 2024; 69:159-182. [PMID: 37625116 DOI: 10.1146/annurev-ento-020123-015755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/27/2023]
Abstract
Dengue, caused by the dengue virus, is the most widespread arboviral infectious disease of public health significance globally. This review explores the communicative function of olfactory cues that mediate host-seeking, egg-laying, plant-feeding, and mating behaviors in Aedes aegypti and Aedes albopictus, two mosquito vectors that drive dengue virus transmission. Aedes aegypti has adapted to live in close association with humans, preferentially feeding on them and laying eggs in human-fabricated water containers and natural habitats. In contrast, Ae. albopictus is considered opportunistic in its feeding habits and tends to inhabit more vegetative areas. Additionally, the ability of both mosquito species to locate suitable host plants for sugars and find mates for reproduction contributes to their survival. Advances in chemical ecology, functional genomics, and behavioral analyses have improved our understanding of the underlying neural mechanisms and reveal novel and specific olfactory semiochemicals that these species use to locate and discriminate among resources in their environment. Physiological status; learning; and host- and habitat-associated factors, including microbial infection and abundance, shape olfactory responses of these vectors. Some of these semiochemicals can be integrated into the toolbox for dengue surveillance and control.
Collapse
Affiliation(s)
- Baldwyn Torto
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya; ,
| | - David P Tchouassi
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya; ,
| |
Collapse
|
3
|
Luker HA. A critical review of current laboratory methods used to evaluate mosquito repellents. FRONTIERS IN INSECT SCIENCE 2024; 4:1320138. [PMID: 38469342 PMCID: PMC10926509 DOI: 10.3389/finsc.2024.1320138] [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: 10/11/2023] [Accepted: 01/02/2024] [Indexed: 03/13/2024]
Abstract
Pathogens transmitted by mosquitoes threaten human health around the globe. The use of effective mosquito repellents can protect individuals from contracting mosquito-borne diseases. Collecting evidence to confirm and quantify the effectiveness of a mosquito repellent is crucial and requires thorough standardized testing. There are multitudes of methods to test repellents that each have their own strengths and weaknesses. Determining which type of test to conduct can be challenging and the collection of currently used and standardized methods has changed over time. Some of these methods can be powerful to rapidly screen numerous putative repellent treatments. Other methods can test mosquito responses to specific treatments and measure either spatial or contact repellency. A subset of these methods uses live animals or human volunteers to test the repellency of treatments. Assays can greatly vary in their affordability and accessibility for researchers and/or may require additional methods to confirm results. Here I present a critical review that covers some of the most frequently used laboratory assays from the last two decades. I discuss the experimental designs and highlight some of the strengths and weaknesses of each type of method covered.
Collapse
Affiliation(s)
- Hailey A. Luker
- Molecular Vector Physiology Laboratory, Department of Biology, New Mexico State University, Las Cruces, NM, United States
| |
Collapse
|
4
|
Hinze A, Pelletier J, Ghaninia M, Marois E, Hill SR, Ignell R. Knockout of OR39 reveals redundancy in the olfactory pathway regulating the acquisition of host seeking in Anopheles coluzzii. Proc Biol Sci 2023; 290:20232092. [PMID: 38018099 PMCID: PMC10685123 DOI: 10.1098/rspb.2023.2092] [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: 09/14/2023] [Accepted: 11/06/2023] [Indexed: 11/30/2023] Open
Abstract
The attraction of anthropophilic mosquitoes to human host cues, such as body odour and carbon dioxide, gradually increases during adult maturation. This acquisition of host-seeking behaviour correlates with age-dependent changes in odorant receptor (OR) transcript abundance and sensitivity of olfactory sensory neurons (OSNs). One OR gene of the human malaria vector, Anopheles coluzzii, AcolOR39, is significantly downregulated in mature females, and a cognate ligand of AcolOR39, sulcatone, a major component of human emanations, mediates the observed behavioural inhibition of newly emerged (teneral) females to human body odour. Knockout of AcolOR39, using CRISPR-Cas9 mutagenesis, selectively abolished sulcatone detection in OSNs, housed in trichoid sensilla. However, knockout of AcolOR39 altered neither the response rate nor the flight behaviour of teneral females in a wind tunnel, indicating the involvement of other genes, and thus a redundancy, in regulating the acquisition of host seeking in mosquitoes.
Collapse
Affiliation(s)
- Annika Hinze
- Disease Vector Group, Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp 750 07, Sweden
| | - Julien Pelletier
- Disease Vector Group, Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp 750 07, Sweden
| | - Majid Ghaninia
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Eric Marois
- Inserm, CNRS, Université de Strasbourg, Strasbourg 67070, France
| | - Sharon Rose Hill
- Disease Vector Group, Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp 750 07, Sweden
| | - Rickard Ignell
- Disease Vector Group, Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp 750 07, Sweden
| |
Collapse
|
5
|
Sarma DK, Kumar M, Dhurve J, Pal N, Sharma P, James MM, Das D, Mishra S, Shubham S, Kumawat M, Verma V, Tiwari RR, Nagpal R, Marotta F. Influence of Host Blood Meal Source on Gut Microbiota of Wild Caught Aedes aegypti, a Dominant Arboviral Disease Vector. Microorganisms 2022; 10:microorganisms10020332. [PMID: 35208787 PMCID: PMC8880539 DOI: 10.3390/microorganisms10020332] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/27/2022] [Accepted: 01/28/2022] [Indexed: 02/07/2023] Open
Abstract
Blood feeding is an important behavior of Aedes aegypti, a dominant arboviral disease vector, as it can establish and transmit viruses to humans. Bacteria associated with the mosquito gut can modulate the biological characteristics and behavior of disease vectors. In this study, we characterized the gut microbiota composition of human-blood-fed (HF), non-human-blood-fed (NHF) and non-fed (NF) field-collected Ae. aegypti mosquitoes, using a 16S metagenomic approach, to assess any association of bacterial taxa with the blood-feeding behavior of Ae. aegypti. A significant difference in the microbiota composition between the HF and NF mosquito group was observed. A significant association was observed in the relative abundance of families Rhodobacteraceae, Neisseriaceae and Dermacoccaceae in the HF group in contrast to NF and NHF Ae. aegypti mosquitoes, respectively. At the class level, two classes (Rhodobacterales and Neisseriales) were found to be in higher abundance in the HF mosquitoes compared to a single class of bacteria (Caulobacterales) in the NF mosquitoes. These results show that human-blood feeding may change the gut microbiota in wild Ae. aegypti populations. More research is needed to determine how changes in the midgut bacterial communities in response to human-blood-feeding affect the vectorial capacity of Ae. aegypti.
Collapse
Affiliation(s)
- Devojit Kumar Sarma
- ICMR—National Institute for Research in Environmental Health, Bhopal Bypass Road, Bhouri, Bhopal 462030, Madhya Pradesh, India; (M.K.); (J.D.); (N.P.); (P.S.); (M.M.J.); (D.D.); (S.M.); (S.S.); (M.K.); (R.R.T.)
- Correspondence: (D.K.S.); (F.M.)
| | - Manoj Kumar
- ICMR—National Institute for Research in Environmental Health, Bhopal Bypass Road, Bhouri, Bhopal 462030, Madhya Pradesh, India; (M.K.); (J.D.); (N.P.); (P.S.); (M.M.J.); (D.D.); (S.M.); (S.S.); (M.K.); (R.R.T.)
| | - Jigyasa Dhurve
- ICMR—National Institute for Research in Environmental Health, Bhopal Bypass Road, Bhouri, Bhopal 462030, Madhya Pradesh, India; (M.K.); (J.D.); (N.P.); (P.S.); (M.M.J.); (D.D.); (S.M.); (S.S.); (M.K.); (R.R.T.)
| | - Namrata Pal
- ICMR—National Institute for Research in Environmental Health, Bhopal Bypass Road, Bhouri, Bhopal 462030, Madhya Pradesh, India; (M.K.); (J.D.); (N.P.); (P.S.); (M.M.J.); (D.D.); (S.M.); (S.S.); (M.K.); (R.R.T.)
| | - Poonam Sharma
- ICMR—National Institute for Research in Environmental Health, Bhopal Bypass Road, Bhouri, Bhopal 462030, Madhya Pradesh, India; (M.K.); (J.D.); (N.P.); (P.S.); (M.M.J.); (D.D.); (S.M.); (S.S.); (M.K.); (R.R.T.)
| | - Meenu Mariya James
- ICMR—National Institute for Research in Environmental Health, Bhopal Bypass Road, Bhouri, Bhopal 462030, Madhya Pradesh, India; (M.K.); (J.D.); (N.P.); (P.S.); (M.M.J.); (D.D.); (S.M.); (S.S.); (M.K.); (R.R.T.)
| | - Deepanker Das
- ICMR—National Institute for Research in Environmental Health, Bhopal Bypass Road, Bhouri, Bhopal 462030, Madhya Pradesh, India; (M.K.); (J.D.); (N.P.); (P.S.); (M.M.J.); (D.D.); (S.M.); (S.S.); (M.K.); (R.R.T.)
| | - Sweta Mishra
- ICMR—National Institute for Research in Environmental Health, Bhopal Bypass Road, Bhouri, Bhopal 462030, Madhya Pradesh, India; (M.K.); (J.D.); (N.P.); (P.S.); (M.M.J.); (D.D.); (S.M.); (S.S.); (M.K.); (R.R.T.)
| | - Swasti Shubham
- ICMR—National Institute for Research in Environmental Health, Bhopal Bypass Road, Bhouri, Bhopal 462030, Madhya Pradesh, India; (M.K.); (J.D.); (N.P.); (P.S.); (M.M.J.); (D.D.); (S.M.); (S.S.); (M.K.); (R.R.T.)
| | - Manoj Kumawat
- ICMR—National Institute for Research in Environmental Health, Bhopal Bypass Road, Bhouri, Bhopal 462030, Madhya Pradesh, India; (M.K.); (J.D.); (N.P.); (P.S.); (M.M.J.); (D.D.); (S.M.); (S.S.); (M.K.); (R.R.T.)
| | - Vinod Verma
- Stem Cell Research Centre, Department of Hematology, Sanjay Gandhi Post-Graduate Institute of Medical Sciences, Lucknow 226014, Uttar Pradesh, India;
| | - Rajnarayan R. Tiwari
- ICMR—National Institute for Research in Environmental Health, Bhopal Bypass Road, Bhouri, Bhopal 462030, Madhya Pradesh, India; (M.K.); (J.D.); (N.P.); (P.S.); (M.M.J.); (D.D.); (S.M.); (S.S.); (M.K.); (R.R.T.)
| | - Ravinder Nagpal
- Department of Nutrition & Integrative Physiology, College of Health & Human Sciences, Florida State University, Tallahassee, FL 32306, USA;
| | - Francesco Marotta
- ReGenera R&D International for Aging Intervention, 20144 Milano, Lombardia, Italy
- Correspondence: (D.K.S.); (F.M.)
| |
Collapse
|
6
|
Amoah B, McCann RS, Kabaghe AN, Mburu M, Chipeta MG, Moraga P, Gowelo S, Tizifa T, van den Berg H, Mzilahowa T, Takken W, van Vugt M, Phiri KS, Diggle PJ, Terlouw DJ, Giorgi E. Identifying Plasmodium falciparum transmission patterns through parasite prevalence and entomological inoculation rate. eLife 2021; 10:65682. [PMID: 34672946 PMCID: PMC8530514 DOI: 10.7554/elife.65682] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 09/30/2021] [Indexed: 11/13/2022] Open
Abstract
Background Monitoring malaria transmission is a critical component of efforts to achieve targets for elimination and eradication. Two commonly monitored metrics of transmission intensity are parasite prevalence (PR) and the entomological inoculation rate (EIR). Comparing the spatial and temporal variations in the PR and EIR of a given geographical region and modelling the relationship between the two metrics may provide a fuller picture of the malaria epidemiology of the region to inform control activities. Methods Using geostatistical methods, we compare the spatial and temporal patterns of Plasmodium falciparum EIR and PR using data collected over 38 months in a rural area of Malawi. We then quantify the relationship between EIR and PR by using empirical and mechanistic statistical models. Results Hotspots identified through the EIR and PR partly overlapped during high transmission seasons but not during low transmission seasons. The estimated relationship showed a 1-month delayed effect of EIR on PR such that at lower levels of EIR, increases in EIR are associated with rapid rise in PR, whereas at higher levels of EIR, changes in EIR do not translate into notable changes in PR. Conclusions Our study emphasises the need for integrated malaria control strategies that combine vector and human host managements monitored by both entomological and parasitaemia indices. Funding This work was supported by Stichting Dioraphte grant number 13050800.
Collapse
Affiliation(s)
- Benjamin Amoah
- Centre for Health Informatics, Computing, and Statistics (CHICAS), Lancaster Medical School, Lancaster University, Lancaster, United Kingdom
| | - Robert S McCann
- Laboratory of Entomology, Wageningen University and Research, Wageningen, Netherlands.,Department of Public Health, College of Medicine, University of Malawi, Blantyre, Malawi.,Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, United States
| | - Alinune N Kabaghe
- Department of Public Health, College of Medicine, University of Malawi, Blantyre, Malawi.,Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Monicah Mburu
- Laboratory of Entomology, Wageningen University and Research, Wageningen, Netherlands.,Department of Public Health, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Michael G Chipeta
- Department of Public Health, College of Medicine, University of Malawi, Blantyre, Malawi.,Malawi-Liverpool Wellcome Trust Research Programme, Blantyre, Malawi.,Big Data Institute, University of Oxford, Oxford, United Kingdom
| | - Paula Moraga
- Centre for Health Informatics, Computing, and Statistics (CHICAS), Lancaster Medical School, Lancaster University, Lancaster, United Kingdom.,Computer, Electrical and Mathematical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Steven Gowelo
- Laboratory of Entomology, Wageningen University and Research, Wageningen, Netherlands.,Department of Public Health, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Tinashe Tizifa
- Department of Public Health, College of Medicine, University of Malawi, Blantyre, Malawi.,Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Henk van den Berg
- Laboratory of Entomology, Wageningen University and Research, Wageningen, Netherlands
| | - Themba Mzilahowa
- Department of Public Health, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Willem Takken
- Laboratory of Entomology, Wageningen University and Research, Wageningen, Netherlands
| | - Michele van Vugt
- Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands
| | - Kamija S Phiri
- Department of Public Health, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Peter J Diggle
- Centre for Health Informatics, Computing, and Statistics (CHICAS), Lancaster Medical School, Lancaster University, Lancaster, United Kingdom
| | - Dianne J Terlouw
- Department of Public Health, College of Medicine, University of Malawi, Blantyre, Malawi.,Malawi-Liverpool Wellcome Trust Research Programme, Blantyre, Malawi.,Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Emanuele Giorgi
- Centre for Health Informatics, Computing, and Statistics (CHICAS), Lancaster Medical School, Lancaster University, Lancaster, United Kingdom
| |
Collapse
|
7
|
Skin bacterial volatiles: propelling the future of vector control. Trends Parasitol 2021; 38:15-22. [PMID: 34548253 DOI: 10.1016/j.pt.2021.08.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/27/2021] [Accepted: 08/27/2021] [Indexed: 12/27/2022]
Abstract
The skin microbiota plays an essential role in the protection against pathogens. It is our skin microbiota that makes us smell different from each other, rendering us more or less attractive to mosquitoes. Mosquitoes exploit skin bacterial odours to locate their hosts and are vectors of pathogens that can cause severe diseases such as malaria and dengue fever. A novel solution for long-lasting protection against insect vectors of disease could be attained by manipulating the bacterial commensals on human skin. The current options for protection against biting insects usually require topical application of repellents that evaporate within hours. We discuss possible routes for the use of commensal bacteria to create a microbial-based repellent.
Collapse
|
8
|
Borrego LG, Ramarosandratana N, Jeanneau E, Métay E, Ramanandraibe VV, Andrianjafy MT, Lemaire M. Effect of the Stereoselectivity of para-Menthane-3,8-diol Isomers on Repulsion toward Aedes albopictus. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:11095-11109. [PMID: 34514794 DOI: 10.1021/acs.jafc.1c03897] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Vector-borne diseases cause around 700,000 deaths every year. Insect repellents are one of the strategies to limit them. Para-menthane-3,8-diol (PMD), a natural compound, is one of the most promising alternatives to conventional synthetic repellents. This work describes a diastereodivergent method to synthesize each diastereoisomer of PMD from enantiopure citronellal and studies their repellence activity against Aedes albopictus. We found that cis-PMD is the kinetic control product of the cyclization of citronellal, while trans-PMD is the thermodynamic control product. X-ray diffraction analysis of crystals highlighted some differences in hydrogen-bond patterns between cis or trans isomers. The present paper demonstrates that (1R)-(+)-cis-PMD has the highest repellency index using a new evaluation system for 24 h. (1S)-(-)-cis-PMD has somewhat lower and (1S)-(+)-trans-PMD and (1R)-(-)-trans-PMD have a slight effect. Volunteer tests show that (1R)-(+)-cis-PMD is the most efficient. This effect could be ascribed to the interaction of PMD/insect odorant receptors and their physical properties, that is, the evaporation rate.
Collapse
Affiliation(s)
- Lorenzo G Borrego
- Université Claude Bernard Lyon 1/CNRS. Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, (ICBMS), 1 rue Victor Grignard, 69100 Villeurbanne, France
| | | | - Erwann Jeanneau
- Centre de Diffactrométrie Henri Longchambon, Université Claude Bernard Lyon 1, 5 rue de la doua, 69100 Villeurbanne, France
| | - Estelle Métay
- Université Claude Bernard Lyon 1/CNRS. Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, (ICBMS), 1 rue Victor Grignard, 69100 Villeurbanne, France
| | | | | | - Marc Lemaire
- Université Claude Bernard Lyon 1/CNRS. Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, (ICBMS), 1 rue Victor Grignard, 69100 Villeurbanne, France
- Faculté des Sciences, Laboratoire International Associé, Antananarivo 101, Madagascar
| |
Collapse
|
9
|
Sorokina M, McCaffrey KS, Deaton EE, Ma G, Ordovás JM, Perkins-Veazie PM, Steinbeck C, Levi A, Parnell LD. A Catalog of Natural Products Occurring in Watermelon- Citrullus lanatus. Front Nutr 2021; 8:729822. [PMID: 34595201 PMCID: PMC8476801 DOI: 10.3389/fnut.2021.729822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 08/09/2021] [Indexed: 12/18/2022] Open
Abstract
Sweet dessert watermelon (Citrullus lanatus) is one of the most important vegetable crops consumed throughout the world. The chemical composition of watermelon provides both high nutritional value and various health benefits. The present manuscript introduces a catalog of 1,679 small molecules occurring in the watermelon and their cheminformatics analysis for diverse features. In this catalog, the phytochemicals are associated with the literature describing their presence in the watermelon plant, and when possible, concentration values in various plant parts (flesh, seeds, leaves, roots, rind). Also cataloged are the chemical classes, molecular weight and formula, chemical structure, and certain physical and chemical properties for each phytochemical. In our view, knowing precisely what is in what we eat, as this catalog does for watermelon, supports both the rationale for certain controlled feeding studies in the field of precision nutrition, and plant breeding efforts for the development of new varieties with enhanced concentrations of specific phytochemicals. Additionally, improved and comprehensive collections of natural products accessible to the public will be especially useful to researchers in nutrition, cheminformatics, bioinformatics, and drug development, among other disciplines.
Collapse
Affiliation(s)
- Maria Sorokina
- Institute for Inorganic and Analytical Chemistry, Friedrich-Schiller University, Jena, Germany
| | | | - Erin E. Deaton
- Department of Horticulture, Plants for Human Health Institute, North Carolina State University, Kannapolis, NC, United States
| | - Guoying Ma
- Department of Horticulture, Plants for Human Health Institute, North Carolina State University, Kannapolis, NC, United States
| | - José M. Ordovás
- Nutrition and Genomics Laboratory, Jean Mayer-United States Department of Agriculture (JM-USDA) Human Nutrition Research Center on Aging at Tufts University, Boston, MA, United States
| | - Penelope M. Perkins-Veazie
- Department of Horticulture, Plants for Human Health Institute, North Carolina State University, Kannapolis, NC, United States
| | - Christoph Steinbeck
- Institute for Inorganic and Analytical Chemistry, Friedrich-Schiller University, Jena, Germany
| | - Amnon Levi
- United States Department of Agriculture (USDA), Agricultural Research Service, U.S. Vegetable Laboratory, Charleston, SC, United States
| | - Laurence D. Parnell
- United States Department of Agriculture (USDA), Agricultural Research Service, Nutrition and Genomics Laboratory, Jean Mayer-United States Department of Agriculture (JM-USDA) Human Nutrition Research Center on Aging at Tufts University, Boston, MA, United States
| |
Collapse
|
10
|
de Boer JG, Kuiper APS, Groot J, van Loon JJA. Avoidance of the Plant Hormone Cis-Jasmone by Aedes aegypti Depends On Mosquito Age in Both Plant and Human Odor Backgrounds. J Chem Ecol 2021; 47:810-818. [PMID: 34463894 PMCID: PMC8473350 DOI: 10.1007/s10886-021-01299-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 07/02/2021] [Accepted: 07/08/2021] [Indexed: 12/14/2022]
Abstract
Adults of many mosquito species feed on plants to obtain metabolic energy and to enhance reproduction. Mosquitoes primarily rely on olfaction to locate plants and are known to respond to a range of plant volatiles. We studied the olfactory response of the yellow fever mosquito Aedes aegypti to methyl jasmonate (MeJA) and cis-jasmone (CiJA), volatile compounds originating from the octadecanoid signaling pathway that plays a key role in plant defense against herbivores. Specifically, we investigated how Ae. aegypti of different ages responded to elevated levels of CiJA in two attractive odor contexts, either derived from Lima bean plants or human skin. Aedes aegypti females landed significantly less often on a surface with CiJA and MeJA compared to the solvent control, CiJA exerting a stronger reduction in landing than MeJA. Odor context (plant or human) had no significant main effect on the olfactory responses of Ae. aegypti females to CiJA. Mosquito age significantly affected the olfactory response, older females (7–9 d) responding more strongly to elevated levels of CiJA than young females (1–3 d) in either odor context. Our results show that avoidance of CiJA by Ae. aegypti is independent of odor background, suggesting that jasmonates are inherently aversive cues to these mosquitoes. We propose that avoidance of plants with elevated levels of jasmonates is adaptive to mosquitoes to reduce the risk of encountering predators that is higher on these plants, i.e. by avoiding ‘enemy-dense-space’.
Collapse
Affiliation(s)
- Jetske G de Boer
- Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.
| | - Aron P S Kuiper
- Laboratory of Entomology, Wageningen University, Wageningen, The Netherlands
| | - Joeri Groot
- Laboratory of Entomology, Wageningen University, Wageningen, The Netherlands
| | - Joop J A van Loon
- Laboratory of Entomology, Wageningen University, Wageningen, The Netherlands
| |
Collapse
|
11
|
Carnaghi M, Belmain SR, Hopkins RJ, Hawkes FM. Multimodal synergisms in host stimuli drive landing response in malaria mosquitoes. Sci Rep 2021; 11:7379. [PMID: 33795798 PMCID: PMC8016827 DOI: 10.1038/s41598-021-86772-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 03/18/2021] [Indexed: 02/01/2023] Open
Abstract
Anopheles mosquitoes transmit malaria, which affects one-fifth of the world population. A comprehensive understanding of mosquito behaviour is essential for the development of novel tools for vector control and surveillance. Despite abundant research on mosquito behaviour, little is known on the stimuli that drive malaria vectors during the landing phase of host-seeking. Using behavioural assays with a multimodal step approach we quantified both the individual and the combined effect of three host-associated stimuli in eliciting landing in Anopheles coluzzii females. We demonstrated that visual, olfactory and thermal sensory stimuli interact synergistically to increase the landing response. Furthermore, if considering only the final outcome (i.e. landing response), our insect model can bypass the absence of either a thermal or a visual stimulus, provided that at least one of these is presented simultaneously with the olfactory stimuli, suggesting that landing is the result of a flexible but accurate stimuli integration. These results have important implications for the development of mosquito control and surveillance tools.
Collapse
Affiliation(s)
- Manuela Carnaghi
- grid.55594.38Department of Agriculture Health and Environment, Natural Resources Institute, University of Greenwich at Medway, Kent, ME7 4TB UK
| | - Steven R. Belmain
- grid.55594.38Department of Agriculture Health and Environment, Natural Resources Institute, University of Greenwich at Medway, Kent, ME7 4TB UK
| | - Richard J. Hopkins
- grid.55594.38Department of Agriculture Health and Environment, Natural Resources Institute, University of Greenwich at Medway, Kent, ME7 4TB UK
| | - Frances M. Hawkes
- grid.55594.38Department of Agriculture Health and Environment, Natural Resources Institute, University of Greenwich at Medway, Kent, ME7 4TB UK
| |
Collapse
|
12
|
Dormont L, Mulatier M, Carrasco D, Cohuet A. Mosquito Attractants. J Chem Ecol 2021; 47:351-393. [PMID: 33725235 DOI: 10.1007/s10886-021-01261-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/18/2021] [Accepted: 03/02/2021] [Indexed: 01/01/2023]
Abstract
Vector control and personal protection against anthropophilic mosquitoes mainly rely on the use of insecticides and repellents. The search for mosquito-attractive semiochemicals has been the subject of intense studies for decades, and new compounds or odor blends are regularly proposed as lures for odor-baited traps. We present a comprehensive and up-to-date review of all the studies that have evaluated the attractiveness of volatiles to mosquitoes, including individual chemical compounds, synthetic blends of compounds, or natural host or plant odors. A total of 388 studies were analysed, and our survey highlights the existence of 105 attractants (77 volatile compounds, 17 organism odors, and 11 synthetic blends) that have been proved effective in attracting one or several mosquito species. The exhaustive list of these attractants is presented in various tables, while the most common mosquito attractants - for which effective attractiveness has been demonstrated in numerous studies - are discussed throughout the text. The increasing knowledge on compounds attractive to mosquitoes may now serve as the basis for complementary vector control strategies, such as those involving lure-and-kill traps, or the development of mass trapping. This review also points out the necessity of further improving the search for new volatile attractants, such as new compound blends in specific ratios, considering that mosquito attraction to odors may vary over the life of the mosquito or among species. Finally, the use of mosquito attractants will undoubtedly have an increasingly important role to play in future integrated vector management programs.
Collapse
Affiliation(s)
- Laurent Dormont
- CEFE, Univ Paul Valéry Montpellier 3, CNRS, Univ Montpellier, EPHE, IRD, Montpellier, France.
| | - Margaux Mulatier
- Institut Pasteur de Guadeloupe, Laboratoire d'étude sur le contrôle des vecteurs (LeCOV), Lieu-Dit Morne Jolivièrex, 97139, Les Abymes, Guadeloupe, France
| | - David Carrasco
- MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France
| | - Anna Cohuet
- MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France
| |
Collapse
|
13
|
Yan J, Gangoso L, Ruiz S, Soriguer R, Figuerola J, Martínez-de la Puente J. Understanding host utilization by mosquitoes: determinants, challenges and future directions. Biol Rev Camb Philos Soc 2021; 96:1367-1385. [PMID: 33686781 DOI: 10.1111/brv.12706] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 02/24/2021] [Accepted: 02/24/2021] [Indexed: 12/29/2022]
Abstract
Mosquito host utilization is a key factor in the transmission of vector-borne pathogens given that it greatly influences host-vector contact rates. Blood-feeding patterns of mosquitoes are not random, as some mosquitoes feed on particular species and/or individuals more than expected by chance. Mosquitoes use a number of cues including visual, olfactory, acoustic, and thermal stimuli emitted by vertebrate hosts to locate and identify their blood meal sources. Thus, differences in the quality/intensity of the released cues may drive host selection by mosquitoes at both inter- and intra-specific levels. Such patterns of host selection by mosquitoes in space and time can be structured by factors related to mosquitoes (e.g. innate host preference, behavioural plasticity), to hosts (e.g. emission of host-seeking cues, host availability) or to both (e.g. pathogen infection). In this study, we review current evidence, from phenomena to mechanisms, of how these factors influence host utilization by mosquitoes. We also review the methodologies commonly used in this research field and identify the major challenges for future studies. To bridge the knowledge gaps, we propose improvements to strengthen traditional approaches and the use of a functional trait-based approach to infer mosquito host utilization in natural communities.
Collapse
Affiliation(s)
- Jiayue Yan
- Doñana Biological Station, Spanish National Research Council (EBD-CSIC), C/Americo Vespucio 26, Seville, 41092, Spain.,Illinois Natural History Survey, University of Illinois, 1816 S Oak St., Champaign, IL, 61821, U.S.A
| | - Laura Gangoso
- Doñana Biological Station, Spanish National Research Council (EBD-CSIC), C/Americo Vespucio 26, Seville, 41092, Spain.,Department of Biodiversity, Ecology and Evolution, Faculty of Biology, Complutense University of Madrid, C/José Antonio Novais 2, Madrid, 28040, Spain
| | - Santiago Ruiz
- CIBER of Epidemiology and Public Health (CIBERESP), Av. Monforte de Lemos 3-5, Madrid, 28029, Spain.,Service of Mosquito Control, Diputación Provincial de Huelva, Ctra. Hospital Infanta Elena s/n, Huelva, 21007, Spain
| | - Ramón Soriguer
- Doñana Biological Station, Spanish National Research Council (EBD-CSIC), C/Americo Vespucio 26, Seville, 41092, Spain.,CIBER of Epidemiology and Public Health (CIBERESP), Av. Monforte de Lemos 3-5, Madrid, 28029, Spain
| | - Jordi Figuerola
- Doñana Biological Station, Spanish National Research Council (EBD-CSIC), C/Americo Vespucio 26, Seville, 41092, Spain.,CIBER of Epidemiology and Public Health (CIBERESP), Av. Monforte de Lemos 3-5, Madrid, 28029, Spain
| | - Josué Martínez-de la Puente
- Doñana Biological Station, Spanish National Research Council (EBD-CSIC), C/Americo Vespucio 26, Seville, 41092, Spain.,CIBER of Epidemiology and Public Health (CIBERESP), Av. Monforte de Lemos 3-5, Madrid, 28029, Spain.,Department of Parasitology, Faculty of Pharmacy, University of Granada (UGR), Campus Universitario de Cartuja, Granada, 18.071, Spain
| |
Collapse
|
14
|
Denz A, Njoroge MM, Tambwe MM, Champagne C, Okumu F, van Loon JJA, Hiscox A, Saddler A, Fillinger U, Moore SJ, Chitnis N. Predicting the impact of outdoor vector control interventions on malaria transmission intensity from semi-field studies. Parasit Vectors 2021; 14:64. [PMID: 33472661 PMCID: PMC7819244 DOI: 10.1186/s13071-020-04560-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 12/21/2020] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Semi-field experiments with human landing catch (HLC) measure as the outcome are an important step in the development of novel vector control interventions against outdoor transmission of malaria since they provide good estimates of personal protection. However, it is often infeasible to determine whether the reduction in HLC counts is due to mosquito mortality or repellency, especially considering that spatial repellents based on volatile pyrethroids might induce both. Due to the vastly different impact of repellency and mortality on transmission, the community-level impact of spatial repellents can not be estimated from such semi-field experiments. METHODS We present a new stochastic model that is able to estimate for any product inhibiting outdoor biting, its repelling effect versus its killing and disarming (preventing host-seeking until the next night) effects, based only on time-stratified HLC data from controlled semi-field experiments. For parameter inference, a Bayesian hierarchical model is used to account for nightly variation of semi-field experimental conditions. We estimate the impact of the products on the vectorial capacity of the given Anopheles species using an existing mathematical model. With this methodology, we analysed data from recent semi-field studies in Kenya and Tanzania on the impact of transfluthrin-treated eave ribbons, the odour-baited Suna trap and their combination (push-pull system) on HLC of Anopheles arabiensis in the peridomestic area. RESULTS Complementing previous analyses of personal protection, we found that the transfluthrin-treated eave ribbons act mainly by killing or disarming mosquitoes. Depending on the actual ratio of disarming versus killing, the vectorial capacity of An. arabiensis is reduced by 41 to 96% at 70% coverage with the transfluthrin-treated eave ribbons and by 38 to 82% at the same coverage with the push-pull system, under the assumption of a similar impact on biting indoors compared to outdoors. CONCLUSIONS The results of this analysis of semi-field data suggest that transfluthrin-treated eave ribbons are a promising tool against malaria transmission by An. arabiensis in the peridomestic area, since they provide both personal and community protection. Our modelling framework can estimate the community-level impact of any tool intervening during the mosquito host-seeking state using data from only semi-field experiments with time-stratified HLC.
Collapse
Affiliation(s)
- Adrian Denz
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.
- University of Basel, Petersplatz 1, Basel, Switzerland.
| | - Margaret M Njoroge
- Human Health Theme, International Centre of Insect Physiology and Ecology (icipe), 00100, Nairobi, Kenya
- Laboratory of Entomology, Wageningen University and Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
| | - Mgeni M Tambwe
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Clara Champagne
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland
- University of Basel, Petersplatz 1, Basel, Switzerland
| | - Fredros Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- School of Public Health, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa
- School of Life Science and Biotechnology, Nelson Mandela African Institution of Science and Technology, P.O. Box 447, Arusha, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Joop J A van Loon
- Laboratory of Entomology, Wageningen University and Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
| | - Alexandra Hiscox
- Laboratory of Entomology, Wageningen University and Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
- ARCTEC, London School of Hygiene and Tropical Medicine, Keppel Street, WC1E 7HT, London, UK
| | - Adam Saddler
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland
- University of Basel, Petersplatz 1, Basel, Switzerland
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Ulrike Fillinger
- Human Health Theme, International Centre of Insect Physiology and Ecology (icipe), 00100, Nairobi, Kenya
| | - Sarah J Moore
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland
- University of Basel, Petersplatz 1, Basel, Switzerland
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Nakul Chitnis
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland
- University of Basel, Petersplatz 1, Basel, Switzerland
| |
Collapse
|
15
|
Ellwanger JH, Cardoso JDC, Chies JAB. Variability in human attractiveness to mosquitoes. CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2021; 1:100058. [PMID: 35284885 PMCID: PMC8906108 DOI: 10.1016/j.crpvbd.2021.100058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 10/20/2021] [Accepted: 10/27/2021] [Indexed: 12/21/2022]
Abstract
Blood-feeding mosquitoes locate humans spatially by detecting a combination of human-derived chemical signals, including carbon dioxide, lactic acid, and other volatile organic compounds. Mosquitoes use these signals to differentiate humans from other animals. Spatial abiotic factors (e.g. humidity, heat) are also used by mosquitoes to find a host. Mosquitoes cause discomfort and harm to humans, being vectors of many pathogens. However, not all humans suffer from mosquito bites with the same frequency or intensity. Some individuals are more attractive to mosquitoes than others, and this has an important impact on the risk of infection by pathogens transmitted by these vectors, such as arboviruses and malaria parasites. Variability in human attractiveness to mosquitoes is partially due to individual characteristics in the composition and intensity in the release of mosquito attractants. The factors that determine these particularities are diverse, modestly understood and still quite controversial. Thus, this review discusses the role of pregnancy, infection with malaria parasites (Plasmodium spp.), skin microbiota, diet, and genetics in human attractiveness to mosquitoes. In brief, pregnancy and Plasmodium infection increase the host attractiveness to mosquitoes. Skin microbiota and human genetics (especially HLA alleles) modulate the production of mosquito attractants and therefore influence individual susceptibility to these insects. There is evidence pointing to a role of diet on human susceptibility to mosquitoes, with some dietary components having a bigger influence than others. In the last part of the review, other factors affecting human-mosquito interactions are debated, with a special focus on the role of mosquito genetics, pathogens and environmental factors (e.g. wind, environmental disturbances). This work highlights that individual susceptibility to mosquitoes is composed of interactions of different human-associated components, environmental factors, and mosquito characteristics. Understanding the importance of these factors, and how they interact with each other, is essential for the development of better mosquito control strategies and studies focused on infectious disease dynamics. Individual human attractiveness to mosquitoes is highly variable. Mosquito attractants released into the air vary from person to person. Variation in attractiveness to mosquitoes alters the risk of mosquito-borne infections. Pregnancy, malaria infection, skin microbiota and genetic factors alter the release of mosquito attractants. Environment and mosquito-related factors affect human–mosquito interactions.
Collapse
Affiliation(s)
- Joel Henrique Ellwanger
- Laboratório de Imunobiologia e Imunogenética, Programa de Pós-Graduação em Genética e Biologia Molecular - PPGBM, Departamento de Genética, Universidade Federal do Rio Grande do Sul - UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
- Corresponding author.
| | - Jáder da Cruz Cardoso
- Divisão de Vigilância Ambiental em Saúde, Centro Estadual de Vigilância em Saúde, Secretaria da Saúde do Estado do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - José Artur Bogo Chies
- Laboratório de Imunobiologia e Imunogenética, Programa de Pós-Graduação em Genética e Biologia Molecular - PPGBM, Departamento de Genética, Universidade Federal do Rio Grande do Sul - UFRGS, Porto Alegre, Rio Grande do Sul, Brazil
| |
Collapse
|
16
|
Martinez J, Showering A, Oke C, Jones RT, Logan JG. Differential attraction in mosquito-human interactions and implications for disease control. Philos Trans R Soc Lond B Biol Sci 2020; 376:20190811. [PMID: 33357061 PMCID: PMC7776937 DOI: 10.1098/rstb.2019.0811] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Mosquito-borne diseases are a major burden on human health worldwide and their eradication through vector control methods remains challenging. In particular, the success of vector control interventions for targeting diseases such as malaria is under threat, in part due to the evolution of insecticide resistance, while for other diseases effective control solutions are still lacking. The rate at which mosquitoes encounter and bite humans is a key determinant of their capacity for disease transmission. Future progress is strongly reliant on improving our understanding of the mechanisms leading to a mosquito bite. Here, we review the biological factors known to influence the attractiveness of mosquitoes to humans, such as body odour, the skin microbiome, genetics and infection by parasites. We identify the knowledge gaps around the relative contribution of each factor, and the potential links between them, as well as the role of natural selection in shaping vector–host–parasite interactions. Finally, we argue that addressing these questions will contribute to improving current tools and the development of novel interventions for the future. This article is part of the theme issue ‘Novel control strategies for mosquito-borne diseases'.
Collapse
Affiliation(s)
- Julien Martinez
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Alicia Showering
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Catherine Oke
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Robert T Jones
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - James G Logan
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| |
Collapse
|
17
|
Loonen JACM, Dery DB, Musaka BZ, Bandibabone JB, Bousema T, van Lenthe M, Pop-Stefanija B, Fesselet JF, Koenraadt CJM. Identification of main malaria vectors and their insecticide resistance profile in internally displaced and indigenous communities in Eastern Democratic Republic of the Congo (DRC). Malar J 2020; 19:425. [PMID: 33228693 PMCID: PMC7684733 DOI: 10.1186/s12936-020-03497-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 11/15/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria remains a major public health concern in the Democratic Republic of the Congo (DRC) and its control is affected by recurrent conflicts. Médecins Sans Frontières (MSF) initiated several studies to better understand the unprecedented incidence of malaria to effectively target and implement interventions in emergency settings. The current study evaluated the main vector species involved in malaria transmission and their resistance to insecticides, with the aim to propose the most effective tools and strategies for control of local malaria vectors. METHODS This study was performed in 52 households in Shamwana (Katanga, 2014), 168 households in Baraka (South Kivu, 2015) and 269 households in Kashuga (North Kivu, 2017). Anopheles vectors were collected and subjected to standardized Word Health Organization (WHO) and Center for Disease Control (CDC) insecticide susceptibility bioassays. Mosquito species determination was done using PCR and Plasmodium falciparum infection in mosquitoes was assessed by ELISA targeting circumsporozoite protein. RESULTS Of 3517 Anopheles spp. mosquitoes collected, Anopheles gambiae sensu lato (s.l.) (29.6%) and Anopheles funestus (69.1%) were the main malaria vectors. Plasmodium falciparum infection rates for An. gambiae s.l. were 1.0, 2.1 and 13.9% for Shamwana, Baraka and Kashuga, respectively. Anopheles funestus showed positivity rates of 1.6% in Shamwana and 4.4% in Baraka. No An. funestus were collected in Kashuga. Insecticide susceptibility tests showed resistance development towards pyrethroids in all locations. Exposure to bendiocarb, malathion and pirimiphos-methyl still resulted in high mosquito mortality. CONCLUSIONS This is one of only few studies from these conflict areas in DRC to report insecticide resistance in local malaria vectors. The data suggest that current malaria prevention methods in these populations are only partially effective, and require additional tools and strategies. Importantly, the results triggered MSF to consider the selection of a new insecticide for indoor residual spraying (IRS) and a new long-lasting insecticide-treated net (LLIN). The reinforcement of correct usage of LLINs and the introduction of targeted larviciding were also included as additional vector control tools as a result of the studies.
Collapse
Affiliation(s)
| | - Dominic B Dery
- Médecins Sans Frontières (MSF), Amsterdam, The Netherlands
| | - Bertin Z Musaka
- Département de Biologie, Centre de Recherche en Sciences Naturelles (CRSN/Lwiro), Bukavu, South Kivu, Democratic Republic of the Congo
| | - Janvier B Bandibabone
- Département de Biologie, Centre de Recherche en Sciences Naturelles (CRSN/Lwiro), Bukavu, South Kivu, Democratic Republic of the Congo
| | - Teun Bousema
- Department of Medical Microbiology, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | | | | | | | | |
Collapse
|
18
|
Kemibala EE, Mafra-Neto A, Saroli J, Silva R, Philbert A, Ng'habi K, Foster WA, Dekker T, Mboera LEG. Is Anopheles gambiae attraction to floral and human skin-based odours and their combination modulated by previous blood meal experience? Malar J 2020; 19:318. [PMID: 32873302 PMCID: PMC7466419 DOI: 10.1186/s12936-020-03395-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/26/2020] [Indexed: 11/21/2022] Open
Abstract
Background Mosquitoes use odours to find energy resources, blood hosts and oviposition sites. While these odour sources are normally spatio-temporally segregated in a mosquito’s life history, here this study explored to what extent a combination of flower- and human-mimicking synthetic volatiles would attract the malaria vector Anopheles gambiae sensu stricto (s.s.) Methods In the laboratory and in large (80 m2) outdoor cages in Tanzania, nulliparous and parous A. gambiae s.s. were offered choices between a blend of human skin volatiles (Skin Lure), a blend of floral volatiles (Vectrax), or a combination thereof. The blends consisted of odours that induce distinct, non-overlapping activation patterns in the olfactory circuitry, in sensory neurons expressing olfactory receptors (ORs) and ionotropic receptors (IRs), respectively. Catches were compared between treatments. Results In the laboratory nulliparous and parous mosquitoes preferred skin odours and combinations thereof over floral odours. However, in semi-field settings nulliparous were significantly more caught with floral odours, whereas no differences were observed for parous females. Combining floral and human volatiles did not augment attractiveness. Conclusions Nulliparous and parous A. gambiae s.s. are attracted to combinations of odours derived from spatio-temporally segregated resources in mosquito life-history (floral and human volatiles). This is favourable as mosquito populations are comprised of individuals whose nutritional and developmental state steer them to diverging odours sources, baits that attract irrespective of mosquito status could enhance overall effectiveness and use in monitoring and control. However, combinations of floral and skin odours did not augment attraction in semi-field settings, in spite of the fact that these blends activate distinct sets of sensory neurons. Instead, mosquito preference appeared to be modulated by blood meal experience from floral to a more generic attraction to odour blends. Results are discussed both from an odour coding, as well as from an application perspective.
Collapse
Affiliation(s)
- Elison E Kemibala
- Ministry of Health, Community Development, Gender, Elderly and Children, Vector Control Training Centre, P.O. Box 136, Muheza, Tanzania. .,University of Dar es Salaam, Dar es Salaam, Tanzania.
| | | | - Jesse Saroli
- ISCA Technologies, 1230, West Spring St, Riverside, CA, 92507, USA
| | - Rodrigo Silva
- ISCA Technologies, 1230, West Spring St, Riverside, CA, 92507, USA
| | | | - Kija Ng'habi
- University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Woodbridge A Foster
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH, USA.,Department of Entomology, The Ohio State University, Columbus, OH, USA
| | - Teun Dekker
- Swedish University of Agricultural Sciences, Alnarp, Uppsala, Sweden.,BioInnovate AB, Lund, Sweden
| | - Leonard E G Mboera
- SACIDS Foundation for One Health, Sokoine University of Agriculture, Morogoro, Tanzania
| |
Collapse
|
19
|
Male swarming aggregation pheromones increase female attraction and mating success among multiple African malaria vector mosquito species. Nat Ecol Evol 2020; 4:1395-1401. [PMID: 32747772 DOI: 10.1038/s41559-020-1264-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 07/03/2020] [Indexed: 02/07/2023]
Abstract
Accumulating behavioural data indicate that aggregation pheromones may mediate the formation and maintenance of mosquito swarms. However, chemical cues possibly luring mosquitoes to swarms have not been adequately investigated, and the likely molecular incitants of these complex reproductive behaviours remain unknown. Here we show that males of the important malaria vector species Anopheles arabiensis and An. gambiae produce and release aggregation pheromones that attract individuals to the swarm and enhance mating success. We found that males of both species released significantly higher amounts of 3-hydroxy-2-butanone (acetoin), 6-methyl-5-hepten-2-one (sulcatone), octanal, nonanal and decanal during swarming in the laboratory. Feeding males with stable-isotope-labelled glucose revealed that the males produced these five compounds. A blend composed of synthetic analogues to these swarming odours proved highly attractive to virgin males and females of both species under laboratory conditions and substantially increased mating in five African malaria vectors (An. gambiae, An. coluzzii, An. arabiensis, An. merus and An. funestus) in semi-field experiments. Our results not only narrow a conspicuous gap in understanding a vital aspect of the chemical ecology of male mosquitoes but also demonstrate fundamental roles of rhythmic and metabolic genes in the physiology and behavioural regulation of these vectors. These identified aggregation pheromones have great potential for exploitation against these highly dangerous insects. Manipulating such pheromones could increase the efficacy of malaria-vector control programmes.
Collapse
|
20
|
Wooding M, Rohwer ER, Naudé Y. Chemical profiling of the human skin surface for malaria vector control via a non-invasive sorptive sampler with GC×GC-TOFMS. Anal Bioanal Chem 2020; 412:5759-5777. [PMID: 32681223 DOI: 10.1007/s00216-020-02799-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 06/26/2020] [Accepted: 07/01/2020] [Indexed: 12/28/2022]
Abstract
Volatile organic compounds (VOCs) and semi-VOCs detected on the human skin surface are of great interest to researchers in the fields of metabolomics, diagnostics, and skin microbiota and in the study of anthropophilic vector mosquitoes. Mosquitoes use chemical cues to find their host, and humans can be ranked for attractiveness to mosquitoes based on their skin chemical profile. Additionally, mosquitoes show a preference to bite certain regions on the human host. In this study, the chemical differences in the skin surface profiles of 20 human volunteers were compared based on inter-human attractiveness to mosquitoes, as well as inter- and intra-human mosquito biting site preference. A passive, non-invasive approach was followed to sample the wrist and ankle skin surface region. An in-house developed polydimethylsiloxane (PDMS) passive sampler was used to concentrate skin VOCs and semi-VOCs prior to thermal desorption directly in the GC inlet with comprehensive gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS). Compounds from a broad range of chemical classes were detected and identified as contributing to the differences in the surface skin chemical profiles. 5-Ethyl-1,2,3,4-tetrahydronaphthalene, 1,1'-oxybisoctane, 2-(dodecyloxy)ethanol, α,α-dimethylbenzene methanol, methyl salicylate, 2,6,10,14-tetramethylhexadecane, 1,2-benzenedicarboxylic acid, bis(2-methylpropyl) ester, 4-methylbenzaldehyde, 2,6-diisopropylnaphthalene, n-hexadecanoic acid, and γ-oxobenzenebutanoic acid ethyl ester were closely associated with individuals who perceived themselves as attractive for mosquitoes. Additionally, biological lead compounds as potential attractants or repellants in vector control strategies were tentatively identified. Results augment current knowledge on human skin chemical profiles and show the potential of using a non-invasive sampling approach to investigate anthropophilic mosquito-host interactions. Graphical abstract.
Collapse
Affiliation(s)
- Madelien Wooding
- Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield, Pretoria, 0028, South Africa
| | - Egmont R Rohwer
- Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield, Pretoria, 0028, South Africa
| | - Yvette Naudé
- Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield, Pretoria, 0028, South Africa.
| |
Collapse
|
21
|
Bakker JW, Loy DE, Takken W, Hahn BH, Verhulst NO. Attraction of mosquitoes to primate odours and implications for zoonotic Plasmodium transmission. MEDICAL AND VETERINARY ENTOMOLOGY 2020; 34:17-26. [PMID: 31420992 PMCID: PMC7002228 DOI: 10.1111/mve.12402] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/18/2019] [Accepted: 07/24/2019] [Indexed: 05/05/2023]
Abstract
Vector-borne diseases often originate from wildlife and can spill over into the human population. One of the most important determinants of vector-borne disease transmission is the host preference of mosquitoes. Mosquitoes with a specialised host preference are guided by body odours to find their hosts in addition to carbon dioxide. Little is known about the role of mosquito host preference in the spillover of pathogenic agents from humans towards animals and vice versa. In the Republic of Congo, the attraction of mosquitoes to primate host odours was determined, as well as their possible role as malaria vectors, using odour-baited traps mimicking the potential hosts of mosquitoes. Most of the mosquito species caught showed a generalistic host preference. Anopheles obscurus was the most abundant Anopheles mosquito, with a generalistic host preference observed from the olfactory response and the detection of various Plasmodium parasites. Interestingly, Culex decens showed a much higher attraction towards chimpanzee odours than to human or cow odours. Human Plasmodium parasites were observed in both human and chimpanzee blood, although not in the Anopheles mosquitoes that were collected. Understanding the role of mosquito host preference for cross-species parasite transmission provides information that will help to determine the risk of spillover of vector-borne diseases.
Collapse
Affiliation(s)
- J. W. Bakker
- Laboratory of EntomologyWageningen University & ResearchWageningenThe Netherlands
| | - D. E. Loy
- Departments of Medicine and Microbiology, Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPAU.S.A.
| | - W. Takken
- Laboratory of EntomologyWageningen University & ResearchWageningenThe Netherlands
| | - B. H. Hahn
- Departments of Medicine and Microbiology, Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPAU.S.A.
| | - N. O. Verhulst
- Laboratory of EntomologyWageningen University & ResearchWageningenThe Netherlands
- National Centre for Vector Entomology, Institute of Parasitology, Vetsuisse FacultyUniversity of ZurichZurichSwitzerland
| |
Collapse
|
22
|
Meng X, Zhong P, Wang Y, Wang H, Tang H, Pan Y. Electrochemical Difunctionalization of Olefines: Access to Selenomethyl‐Substituted Cyclic Ethers or Lactones. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201901115] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Xiu‐Jin Meng
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences Guangxi Normal University Guilin 541004 People's Republic of China
| | - Ping‐Fu Zhong
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences Guangxi Normal University Guilin 541004 People's Republic of China
| | - Yu‐Mei Wang
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences Guangxi Normal University Guilin 541004 People's Republic of China
| | - Heng‐Shan Wang
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences Guangxi Normal University Guilin 541004 People's Republic of China
| | - Hai‐Tao Tang
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences Guangxi Normal University Guilin 541004 People's Republic of China
| | - Ying‐Ming Pan
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences Guangxi Normal University Guilin 541004 People's Republic of China
- Guangxi Key Laboratory of Agricultural Resources Chemistry and Biotechnology Yulin Normal University Yuilin 537000 People's Republic of China
| |
Collapse
|
23
|
Ciera L, Beladjal L, Van Landuyt L, Menger D, Holdinga M, Mertens J, Van Langenhove L, De Clerk K, Gheysens T. Electrospinning repellents in polyvinyl alcohol-nanofibres for obtaining mosquito-repelling fabrics. ROYAL SOCIETY OPEN SCIENCE 2019; 6:182139. [PMID: 31598223 PMCID: PMC6731725 DOI: 10.1098/rsos.182139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 07/24/2019] [Indexed: 06/10/2023]
Abstract
Recently, the use of repellents for preventing the transmission of mosquito-borne diseases is getting increasingly more attention. However, most of the current repellents are volatile in nature and must be frequently re-applied as their efficacy is only limited to a short period of time. Therefore, a slow release and abrasion-resistant mechanism is needed for prolonging the protection time of the repellents. The focus of this study is on the direct micro-encapsulation of repellents from an emulsion and integration of already encapsulated repellents into nanofibres via electrospinning. Different repellents were electrospun in polyvinyl alcohol (PVA) nanofibrous structures, namely p-menthane-3,8-diol micro-capsules, permethrin, chilli and catnip oil. The repellents were successfully incorporated in the nanofibres and the tensile properties of the resulting samples did not have a significant change. This means that the newly created textiles were identical to current PVA nanofibrous textiles with the added benefit of being mosquito repellent. Principally, all incorporated repellents in the nanofibrous structures showed a significantly reduced number of mosquito landings compared to the control. Consequently, the currently described method resulted in a new and very effective repelling textile material that can be used in the prevention against mosquito-associated diseases.
Collapse
Affiliation(s)
- Lucy Ciera
- The Technical University of Kenya, Nairobi, Kenya
| | - Lynda Beladjal
- Biology Department, Ghent University, Terrestrial Ecology Unit, Gent, Belgium
| | - Lieve Van Landuyt
- Textile Department, Ghent University, Technologiepark, Zwijnaarde, Belgium
| | - David Menger
- Laboratory of Entomology, Wageningen University, Wageningen, The Netherlands
| | - Maarten Holdinga
- Laboratory of Entomology, Wageningen University, Wageningen, The Netherlands
| | - Johan Mertens
- Biology Department, Ghent University, Terrestrial Ecology Unit, Gent, Belgium
| | | | - Karen De Clerk
- Textile Department, Ghent University, Technologiepark, Zwijnaarde, Belgium
| | - Tom Gheysens
- Textile Department, Ghent University, Technologiepark, Zwijnaarde, Belgium
- Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| |
Collapse
|
24
|
Olaide OY, Tchouassi DP, Yusuf AA, Pirk CWW, Masiga DK, Saini RK, Torto B. Zebra skin odor repels the savannah tsetse fly, Glossina pallidipes (Diptera: Glossinidae). PLoS Negl Trop Dis 2019; 13:e0007460. [PMID: 31181060 PMCID: PMC6586361 DOI: 10.1371/journal.pntd.0007460] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 06/20/2019] [Accepted: 05/11/2019] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND African trypanosomosis, primarily transmitted by tsetse flies, remains a serious public health and economic challenge in sub-Saharan Africa. Interventions employing natural repellents from non-preferred hosts of tsetse flies represent a promising management approach. Although zebras have been identified as non-preferred hosts of tsetse flies, the basis for this repellency is poorly understood. We hypothesized that zebra skin odors contribute to their avoidance by tsetse flies. METHODOLOGY/PRINCIPAL FINDINGS We evaluated the effect of crude zebra skin odors on catches of wild savannah tsetse flies (Glossina pallidipes Austen, 1903) using unbaited Ngu traps compared to the traps baited with two known tsetse fly management chemicals; a repellent blend derived from waterbuck odor, WRC (comprising geranylacetone, guaiacol, pentanoic acid and δ-octalactone), and an attractant comprising cow urine and acetone, in a series of Latin square-designed experiments. Coupled gas chromatography-electroantennographic detection (GC/EAD) and GC-mass spectrometry (GC/MS) analyses of zebra skin odors identified seven electrophysiologically-active components; 6-methyl-5-hepten-2-one, acetophenone, geranylacetone, heptanal, octanal, nonanal and decanal, which were tested in blends and singly for repellency to tsetse flies when combined with Ngu traps baited with cow urine and acetone in field trials. The crude zebra skin odors and a seven-component blend of the EAD-active components, formulated in their natural ratio of occurrence in zebra skin odor, significantly reduced catches of G. pallidipesby 66.7% and 48.9% respectively, and compared favorably with the repellency of WRC (58.1%- 59.2%). Repellency of the seven-component blend was attributed to the presence of the three ketones 6-methyl-5-hepten-2-one, acetophenone and geranylacetone, which when in a blend caused a 62.7% reduction in trap catch of G. pallidipes. CONCLUSIONS/SIGNIFICANCE Our findings reveal fundamental insights into tsetse fly ecology and the allomonal effect of zebra skin odor, and potential integration of the three-component ketone blend into the management toolkit for tsetse and African trypanosomosis control.
Collapse
Affiliation(s)
- Olabimpe Y. Olaide
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
- * E-mail: ,
| | - David P. Tchouassi
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Abdullahi A. Yusuf
- Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Christian W. W. Pirk
- Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Daniel K. Masiga
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Rajinder K. Saini
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Baldwyn Torto
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| |
Collapse
|
25
|
Optimal Strategies for Dengue Prevention and Control during Daily Commuting between Two Residential Areas. Processes (Basel) 2019. [DOI: 10.3390/pr7040197] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
: In this paper, we report an application for the mathematical theory of dynamic optimization for design of optimal strategies that account for daily commuting of human residents, aiming to reduce vector-borne infections (dengue) among human populations. Our analysis is based on a two-patch dengue transmission model amended with control variables that represent personal protection measures aimed at reduction of the number of contacts between mosquitoes and human hosts (e.g., the use of repellents, mosquito nets, or insecticide-treated clothing). As a result, we have proposed and numerically solved an optimal control problem to minimize the costs associated with the application of control measures, while also minimizing the total number of dengue-infected people in both residential areas. Our principal goal was to identify an optimal strategy for personal protection that renders the maximal number of averted human infections per unit of invested cost, and this goal has been accomplished on the grounds of cost-effectiveness analysis.
Collapse
|
26
|
Mburu MM, Zembere K, Hiscox A, Banda J, Phiri KS, van den Berg H, Mzilahowa T, Takken W, McCann RS. Assessment of the Suna trap for sampling mosquitoes indoors and outdoors. Malar J 2019; 18:51. [PMID: 30795766 PMCID: PMC6387520 DOI: 10.1186/s12936-019-2680-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 02/14/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Entomological monitoring is important for public health because it provides data on the distribution, abundance and host-seeking behaviour of disease vectors. Various methods for sampling mosquitoes exist, most of which are biased towards, or specifically target, certain portions of a mosquito population. This study assessed the Suna trap, an odour-baited trap for sampling host-seeking mosquitoes both indoors and outdoors. METHODS Two separate field experiments were conducted in villages in southern Malawi. The efficiency of the Suna trap in sampling mosquitoes was compared to that of the human landing catch (HLC) indoors and outdoors and the Centers for Disease, Control and Prevention Light Trap (CDC-LT) indoors. Potential competition between two Suna traps during simultaneous use of the traps indoors and outdoors was assessed by comparing mosquito catch sizes across three treatments: one trap indoors only; one trap outdoors only; and one trap indoors and one trap outdoors used simultaneously at the same house. RESULTS The efficiency of the Suna trap in sampling female anophelines was similar to that of HLC indoors (P = 0.271) and HLC outdoors (P = 0.125), but lower than that of CDC-LT indoors (P = 0.001). Anopheline catch sizes in the Suna trap used alone indoors were similar to indoor Suna trap catch sizes when another Suna trap was simultaneously present outdoors (P = 0.891). Similarly, catch sizes of female anophelines with the Suna trap outdoors were similar to those that were caught outdoors when another Suna trap was simultaneously present indoors (P = 0.731). CONCLUSIONS The efficiency of the Suna trap in sampling mosquitoes was equivalent to that of the HLC. Whereas the CDC-LT was more efficient in collecting female anophelines indoors, the use of this trap outdoors is limited given the requirement of setting it next to an occupied bed net. As demonstrated in this research, outdoor collections are also essential because they provide data on the relative contribution of outdoor biting to malaria transmission. Therefore, the Suna trap could serve as an alternative to the HLC and the CDC-LT, because it does not require the use of humans as natural baits, allows standardised sampling conditions across sampling points, and can be used outdoors. Furthermore, using two Suna traps simultaneously indoors and outdoors does not interfere with the sampling efficiency of either trap, which would save a considerable amount of time, energy, and resources compared to setting the traps indoors and then outdoors in two consecutive nights.
Collapse
Affiliation(s)
- Monicah M Mburu
- College of Medicine, University of Malawi, Blantyre, Malawi. .,Laboratory of Entomology, Wageningen University and Research, Wageningen, The Netherlands.
| | | | - Alexandra Hiscox
- Laboratory of Entomology, Wageningen University and Research, Wageningen, The Netherlands
| | - Jomo Banda
- College of Medicine, University of Malawi, Blantyre, Malawi.,MAC Communicable Diseases Action Centre, Blantyre, Malawi
| | - Kamija S Phiri
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - Henk van den Berg
- Laboratory of Entomology, Wageningen University and Research, Wageningen, The Netherlands
| | - Themba Mzilahowa
- College of Medicine, University of Malawi, Blantyre, Malawi.,MAC Communicable Diseases Action Centre, Blantyre, Malawi
| | - Willem Takken
- Laboratory of Entomology, Wageningen University and Research, Wageningen, The Netherlands
| | - Robert S McCann
- College of Medicine, University of Malawi, Blantyre, Malawi.,Laboratory of Entomology, Wageningen University and Research, Wageningen, The Netherlands
| |
Collapse
|
27
|
Batista EPA, Ngowo H, Opiyo M, Shubis GK, Meza FC, Siria DJ, Eiras AE, Okumu FO. Field evaluation of the BG-Malaria trap for monitoring malaria vectors in rural Tanzanian villages. PLoS One 2018; 13:e0205358. [PMID: 30296287 PMCID: PMC6175526 DOI: 10.1371/journal.pone.0205358] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 09/24/2018] [Indexed: 11/19/2022] Open
Abstract
BG-Malaria (BGM) trap is a simple adaptation of the widely-used BG-Sentinel trap (BGS). It is proven to be highly effective for trapping the Brazilian malaria vector, Anopheles darlingi, in field conditions, and the African vector, Anopheles arabiensis, under controlled semi-field environments, but has not been field-tested in Africa. Here, we validated the BGM for field sampling of malaria vectors in south-eastern Tanzania. Using a series of Latin-Square experiments conducted nightly (6pm-7am) in rural villages, we compared mosquito catches between BGM, BGS and human landing catches (HLC). We also compared BGMs baited with different attractants (Ifakara-blend, Mbita-blend, BG-Lure and CO2). Lastly, we tested BGMs baited with Ifakara-blend from three odour-dispensing methods (BG-Cartridge, BG-Sachet and Nylon strips). One-tenth of the field-collected female Anopheles gambiae s.l. and Anopheles funestus were dissected to assess parity. BGM captured more An. gambiae s.l. than BGS (p < 0.001), but HLC caught more than either trap (p < 0.001). However, BGM captured more An. funestus than HLC. Proportions of parous An. gambiae s.l. and An. funestus consistently exceeded 50%, with no significant difference between methods. While the dominant species caught by HLC was An. gambiae s.l. (56.0%), followed by Culex spp. (33.1%) and Mansonia spp. (6.0%), the BGM caught mostly Culex (81.6%), followed by An. gambiae s.l. (10.6%) and Mansonia (5.8%). The attractant-baited BGMs were all significantly superior to un-baited controls (p < 0.001), although no difference was found between the specific attractants. The BG-Sachet was the most efficient dispenser for capturing An. gambiae s.l. (14.5(2.75–42.50) mosquitoes/trap/night), followed by BG-Cartridge (7.5(1.75–26.25)). The BGM caught more mosquitoes than BGS in field-settings, but sampled similar species diversity and physiological states as BGS. The physiological states of malaria vectors caught in BGM and BGS were similar to those naturally attempting to bite humans (HLC). The BGM was most efficient when baited with Ifakara blend, dispensed from BG-Sachet. We conclude that though BGM traps have potential for field-sampling of host-seeking African malaria vectors with representative physiological states, both BGM and BGS predominantly caught more culicines than Anopheles, compared to HLC, which caught mostly An. gambiae s.l.
Collapse
Affiliation(s)
- Elis P. A. Batista
- Laboratório de Ecologia Química de Insetos Vetores, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- * E-mail:
| | - Halfan Ngowo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Mercy Opiyo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Gasper K. Shubis
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Felician C. Meza
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Doreen J. Siria
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Alvaro E. Eiras
- Laboratório de Ecologia Química de Insetos Vetores, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Fredros O. Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Republic of South Africa
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| |
Collapse
|
28
|
Tavares DDS, Salgado VR, Miranda JC, Mesquita PRR, Rodrigues FDM, Barral-Netto M, de Andrade JB, Barral A. Attraction of phlebotomine sandflies to volatiles from skin odors of individuals residing in an endemic area of tegumentary leishmaniasis. PLoS One 2018; 13:e0203989. [PMID: 30248113 PMCID: PMC6152958 DOI: 10.1371/journal.pone.0203989] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 09/02/2018] [Indexed: 01/24/2023] Open
Abstract
Background Many studies have investigated what could attract insects of medical importance and a crucial role has lately been attributed to human skin odors. Most of these researches have been concerned with mosquitoes, e.g., vectors of dengue and malaria. Little is known about volatile organic compounds (VOCs) from human skin odors and their effects on leishmania vectors. Objective The present study aimed to identify the VOCs from human skin that can be attractive to female anthropophilic phlebotomine sandflies. Results Forty-two VOCs were identified from skin odors of 33 male volunteers, seven of which were tested in wind tunnel assays employing field-captured phlebotomine sandflies (75.4% identified as Lutzomyia intermedia). Hexane and (E)-oct-3-en-1-ol (octenol) were used as negative and positive controls, respectively. 2-Phenylacetaldehyde (hereafter called phenylacetaldehyde), 6-methylhept-5-en-2-one (also known as sulcatone), nonadecane and icosane were found to activate female phlebotomine sandflies, but only phenylacetaldehyde, 6-methylhepten-5-en-2-one and icosane elicited attraction responses. Conclusions These results suggest that phenylacetaldehyde, 6-methylhepten-5-en-2-one and icosane may be suitable candidates for attractiveness experimentation in the field which can be an important tool to develop strategies concerning human beings protection against phlebotomine sandflies bites and consequently against leishmaniasis.
Collapse
Affiliation(s)
- Diva da Silva Tavares
- Instituto Gonçalo Moniz—Fiocruz–Salvador, Bahia—Brazil
- Faculdade de Medicina da Universidade Federal da Bahia (UFBA)–Salvador, Bahia–Brazil
- Faculdade de Medicina do Centro Universitário Christus (UNICHRISTUS)–Fortaleza, Ceará –Brazil
- * E-mail: (DDST); (AB)
| | | | | | - Paulo R. R. Mesquita
- Instituto de Química da Universidade Federal da Bahia (UFBA)–Salvador, Bahia–Brazil
| | | | - Manoel Barral-Netto
- Instituto Gonçalo Moniz—Fiocruz–Salvador, Bahia—Brazil
- Faculdade de Medicina da Universidade Federal da Bahia (UFBA)–Salvador, Bahia–Brazil
- Instituto Nacional de Ciência e Tecnologia de Investigação em Imunologia (iii-INCT)–Salvador, Bahia–Brazil
| | - Jailson Bittencourt de Andrade
- Instituto de Química da Universidade Federal da Bahia (UFBA)–Salvador, Bahia–Brazil
- Instituto Nacional de Ciência e Tecnologia em Energia e Ambiente (INCT-EA)–Salvador, Bahia–Brazil
| | - Aldina Barral
- Instituto Gonçalo Moniz—Fiocruz–Salvador, Bahia—Brazil
- Faculdade de Medicina da Universidade Federal da Bahia (UFBA)–Salvador, Bahia–Brazil
- Instituto Nacional de Ciência e Tecnologia de Investigação em Imunologia (iii-INCT)–Salvador, Bahia–Brazil
- * E-mail: (DDST); (AB)
| |
Collapse
|
29
|
Roodt AP, Naudé Y, Stoltz A, Rohwer E. Human skin volatiles: Passive sampling and GC × GC-ToFMS analysis as a tool to investigate the skin microbiome and interactions with anthropophilic mosquito disease vectors. J Chromatogr B Analyt Technol Biomed Life Sci 2018; 1097-1098:83-93. [PMID: 30212730 DOI: 10.1016/j.jchromb.2018.09.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/16/2018] [Accepted: 09/01/2018] [Indexed: 12/18/2022]
Abstract
Volatile organic compounds (VOCs) emanating from the surfaces of human skin are of great interest to researchers in medical and forensic fields, as well as to biologists studying the ecology of blood-feeding insect vectors of human disease. Research involving the comparison of relative abundances of VOCs emanating from human skin is currently limited by the methodology used for sample collection and pre-concentration. The use of in-house developed silicone rubber (polydimethylsiloxane (PDMS)) passive sampling devices constructed in the form of bracelets and anklets was explored to address this need. The easy-to-use samplers were employed as non-invasive passive sampling devices for the non-targeted collection and concentration of volatile human skin emissions prior to thermal desorption thereof coupled with comprehensive gas chromatographic time-of-flight mass spectrometric (GC × GC-TOFMS) analysis. Compounds collected were from a wide range of compound classes. Several compounds, notably cyclic ketones, identified have not been previously reported in skin volatile literature. Comparison of normalized unique mass peak area signals has revealed relative quantitative differences and similarities between the samples collected from two individuals' wrists and as well as between an individual's wrist and ankle. The sampling method was evaluated based on its ability to provide many candidate compounds for potential biomarker discovery. The results show the ability of the new sampling method for augmenting the current knowledge on human skin volatile emissions. The samplers are both easy to use and economical. Applications explored include the study of the complex relationships between the human skin microbiome and the attractiveness of individuals to anthropophilic blood host seeking mosquitoes.
Collapse
Affiliation(s)
- Alexis P Roodt
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa
| | - Yvette Naudé
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa.
| | - Anton Stoltz
- Division of Infectious Diseases, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Egmont Rohwer
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa
| |
Collapse
|
30
|
Abstract
Malaria parasites (Plasmodium) can change the attractiveness of their vertebrate hosts to Anopheles vectors, leading to a greater number of vector-host contacts and increased transmission. Indeed, naturally Plasmodium-infected children have been shown to attract more mosquitoes than parasite-free children. Here, we demonstrate Plasmodium-induced increases in the attractiveness of skin odor in Kenyan children and reveal quantitative differences in the production of specific odor components in infected vs. parasite-free individuals. We found the aldehydes heptanal, octanal, and nonanal to be produced in greater amounts by infected individuals and detected by mosquito antennae. In behavioral experiments, we demonstrated that these, and other, Plasmodium-induced aldehydes enhanced the attractiveness of a synthetic odor blend mimicking "healthy" human odor. Heptanal alone increased the attractiveness of "parasite-free" natural human odor. Should the increased production of these aldehydes by Plasmodium-infected humans lead to increased mosquito biting in a natural setting, this would likely affect the transmission of malaria.
Collapse
|
31
|
Spitzen J, Takken W. Keeping track of mosquitoes: a review of tools to track, record and analyse mosquito flight. Parasit Vectors 2018; 11:123. [PMID: 29499744 PMCID: PMC5834890 DOI: 10.1186/s13071-018-2735-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 02/21/2018] [Indexed: 12/13/2022] Open
Abstract
The health impact of mosquito-borne diseases causes a huge burden on human societies. Recent vector control campaigns have resulted in promising declines in incidence and prevalence of these diseases, notably malaria, but resistance to insecticides and drugs are on the rise, threatening to overturn these gains. Moreover, several vector-borne diseases have re-emerged, requiring prompt and effective response measures. To improve and properly implement vector control interventions, the behaviour of the vectors must be well understood with detailed examination of mosquito flight being an essential component. Current knowledge on mosquito behaviour across its life history is briefly presented, followed by an overview of recent developments in automated tracking techniques for detailed interpretation of mosquito behaviour. These techniques allow highly accurate recording and observation of mating, feeding and oviposition behaviour. Software programmes built with specific algorithms enable quantification of these behaviours. For example, the crucial role of heat on host landing and the multimodal integration of carbon dioxide (CO2) with other host cues, has been unravelled based on three-dimensional tracking of mosquito flight behaviour. Furthermore, the behavioural processes underlying house entry and subsequent host searching and finding can be better understood by analysis of detailed flight recordings. Further potential of these technologies to solve knowledge gaps is discussed. The use of tracking techniques can support or replace existing monitoring tools and provide insights on mosquito behaviour that can lead to innovative and more effective vector-control measures.
Collapse
Affiliation(s)
- Jeroen Spitzen
- Laboratory of Entomology, Wageningen University and Research, PO Box 16, 6700 AA Wageningen, The Netherlands
| | - Willem Takken
- Laboratory of Entomology, Wageningen University and Research, PO Box 16, 6700 AA Wageningen, The Netherlands
| |
Collapse
|
32
|
Abstract
Basic science holds enormous power for revealing the biological mechanisms of disease and, in turn, paving the way toward new, effective interventions. Recognizing this power, the 2011 Research Agenda for Malaria Eradication included key priorities in fundamental research that, if attained, could help accelerate progress toward disease elimination and eradication. The Malaria Eradication Research Agenda (malERA) Consultative Panel on Basic Science and Enabling Technologies reviewed the progress, continuing challenges, and major opportunities for future research. The recommendations come from a literature of published and unpublished materials and the deliberations of the malERA Refresh Consultative Panel. These areas span multiple aspects of the Plasmodium life cycle in both the human host and the Anopheles vector and include critical, unanswered questions about parasite transmission, human infection in the liver, asexual-stage biology, and malaria persistence. We believe an integrated approach encompassing human immunology, parasitology, and entomology, and harnessing new and emerging biomedical technologies offers the best path toward addressing these questions and, ultimately, lowering the worldwide burden of malaria.
Collapse
|
33
|
Semi-field assessment of the BG-Malaria trap for monitoring the African malaria vector, Anopheles arabiensis. PLoS One 2017; 12:e0186696. [PMID: 29045484 PMCID: PMC5646867 DOI: 10.1371/journal.pone.0186696] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 10/05/2017] [Indexed: 11/19/2022] Open
Abstract
Odour-baited technologies are increasingly considered for effective monitoring of mosquito populations and for the evaluation of vector control interventions. The BG-Malaria trap (BGM), which is an upside-down variant of the widely used BG-Sentinel trap (BGS), has been demonstrated to be effective to sample the Brazilian malaria vector, Anopheles darlingi. We evaluated the BGM as an improved method for sampling the African malaria vectors, Anopheles arabiensis. Experiments were conducted inside a large semi-field cage to compare trapping efficiencies of BGM and BGS traps, both baited with the synthetic attractant, Ifakara blend, supplemented with CO2. We then compared BGMs baited with either of four synthetic mosquito lures, Ifakara blend, Mbita blend, BG-lure or CO2, and an unbaited BGM. Lastly, we compared BGMs baited with the Ifakara blend dispensed via either nylon strips, BG cartridges (attractant-infused microcapsules encased in cylindrical plastic cartridge) or BG sachets (attractant-infused microcapsules encased in plastic sachets). All tests were conducted between 6P.M. and 7A.M., with 200–600 laboratory-reared An. arabiensis released nightly in the test chamber. The median number of An. arabiensis caught by the BGM per night was 83, IQR:(73.5–97.75), demonstrating clear superiority over BGS (median catch = 32.5 (25.25–37.5)). Compared to unbaited controls, BGMs baited with Mbita blend caught most mosquitoes (45 (29.5–70.25)), followed by BGMs baited with CO2 (42.5 (27.5–64)), Ifakara blend (31 (9.25–41.25)) and BG lure (16 (4–22)). BGM caught 51 (29.5–72.25) mosquitoes/night, when the attractants were dispensed using BG-Cartridges, compared to BG-Sachet (29.5 (24.75–40.5)), and nylon strips (27 (19.25–38.25)), in all cases being significantly superior to unbaited controls (p < 000.1). The findings demonstrate potential of the BGM as a sampling tool for African malaria vectors over the standard BGS trap. Its efficacy can be optimized by selecting appropriate odour baits and odour-dispensing systems.
Collapse
|
34
|
McCann RS, van den Berg H, Diggle PJ, van Vugt M, Terlouw DJ, Phiri KS, Di Pasquale A, Maire N, Gowelo S, Mburu MM, Kabaghe AN, Mzilahowa T, Chipeta MG, Takken W. Assessment of the effect of larval source management and house improvement on malaria transmission when added to standard malaria control strategies in southern Malawi: study protocol for a cluster-randomised controlled trial. BMC Infect Dis 2017; 17:639. [PMID: 28938876 PMCID: PMC5610449 DOI: 10.1186/s12879-017-2749-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 09/19/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Due to outdoor and residual transmission and insecticide resistance, long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) will be insufficient as stand-alone malaria vector control interventions in many settings as programmes shift toward malaria elimination. Combining additional vector control interventions as part of an integrated strategy would potentially overcome these challenges. Larval source management (LSM) and structural house improvements (HI) are appealing as additional components of an integrated vector management plan because of their long histories of use, evidence on effectiveness in appropriate settings, and unique modes of action compared to LLINs and IRS. Implementation of LSM and HI through a community-based approach could provide a path for rolling-out these interventions sustainably and on a large scale. METHODS/DESIGN We will implement community-based LSM and HI, as additional interventions to the current national malaria control strategies, using a randomised block, 2 × 2 factorial, cluster-randomised design in rural, southern Malawi. These interventions will be continued for two years. The trial catchment area covers about 25,000 people living in 65 villages. Community participation is encouraged by training community volunteers as health animators, and supporting the organisation of village-level committees in collaboration with The Hunger Project, a non-governmental organisation. Household-level cross-sectional surveys, including parasitological and entomological sampling, will be conducted on a rolling, 2-monthly schedule to measure outcomes over two years (2016 to 2018). Coverage of LSM and HI will also be assessed throughout the trial area. DISCUSSION Combining LSM and/or HI together with the interventions currently implemented by the Malawi National Malaria Control Programme is anticipated to reduce malaria transmission below the level reached by current interventions alone. Implementation of LSM and HI through a community-based approach provides an opportunity for optimum adaptation to the local ecological and social setting, and enhances the potential for sustainability. TRIAL REGISTRATION Registered with The Pan African Clinical Trials Registry on 3 March 2016, trial number PACTR201604001501493.
Collapse
Affiliation(s)
- Robert S McCann
- Wageningen University and Research, Wageningen, The Netherlands. .,College of Medicine, University of Malawi, Blantyre, Malawi. .,Laboratory of Entomology, Wageningen University and Research, PO Box 16, 6700, AA, Wageningen, The Netherlands.
| | | | | | - Michèle van Vugt
- Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Dianne J Terlouw
- Liverpool School of Tropical Medicine, Liverpool, UK.,Malawi-Liverpool Wellcome Trust, Blantyre, Malawi
| | - Kamija S Phiri
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - Aurelio Di Pasquale
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Nicolas Maire
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Steven Gowelo
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - Monicah M Mburu
- Wageningen University and Research, Wageningen, The Netherlands.,College of Medicine, University of Malawi, Blantyre, Malawi
| | - Alinune N Kabaghe
- College of Medicine, University of Malawi, Blantyre, Malawi.,Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Michael G Chipeta
- College of Medicine, University of Malawi, Blantyre, Malawi.,Lancaster University, Lancaster, UK.,Malawi-Liverpool Wellcome Trust, Blantyre, Malawi
| | - Willem Takken
- Wageningen University and Research, Wageningen, The Netherlands
| |
Collapse
|
35
|
Odours of Plasmodium falciparum-infected participants influence mosquito-host interactions. Sci Rep 2017; 7:9283. [PMID: 28839251 PMCID: PMC5570919 DOI: 10.1038/s41598-017-08978-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 07/17/2017] [Indexed: 11/29/2022] Open
Abstract
Malaria parasites are thought to influence mosquito attraction to human hosts, a phenomenon that may enhance parasite transmission. This is likely mediated by alterations in host odour because of its importance in mosquito host-searching behaviour. Here, we report that the human skin odour profile is affected by malaria infection. We compared the chemical composition and attractiveness to Anopheles coluzzii mosquitoes of skin odours from participants that were infected by Controlled Human Malaria Infection with Plasmodium falciparum. Skin odour composition differed between parasitologically negative and positive samples, with positive samples collected on average two days after parasites emerged from the liver into the blood, being associated with low densities of asexual parasites and the absence of gametocytes. We found a significant reduction in mosquito attraction to skin odour during infection for one experiment, but not in a second experiment, possibly due to differences in parasite strain. However, it does raise the possibility that infection can affect mosquito behaviour. Indeed, several volatile compounds were identified that can influence mosquito behaviour, including 2- and 3-methylbutanal, 3-hydroxy-2-butanone, and 6-methyl-5-hepten-2-one. To better understand the impact of our findings on Plasmodium transmission, controlled studies are needed in participants with gametocytes and higher parasite densities.
Collapse
|
36
|
Briët OJT, Yukich JO, Pfeiffer C, Miller W, Jaeger MS, Khanna N, Oppong S, Nardini P, Ahorlu CK, Keating J. The effect of small solar powered 'Bͻkͻͻ' net fans on mosquito net use: results from a randomized controlled cross-over trial in southern Ghana. Malar J 2017; 16:12. [PMID: 28049477 PMCID: PMC5209841 DOI: 10.1186/s12936-016-1654-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 12/15/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Long-lasting insecticidal nets (LLINs) are ineffective malaria transmission prevention tools if they are unused. Discomfort due to heat is the most commonly reported reason for not using nets, but this problem is largely unaddressed. With increasing rural electrification and the dropping price of solar power, fans could improve comfort inside nets and be affordable to populations in malaria endemic areas. Here, results are presented from a pilot randomized controlled cross-over study testing the effect of fans on LLIN use. METHODS Eighty-three households from two rural communities in Greater Accra, Ghana, randomized into three groups, participated in a 10-month cross-over trial. After a screening survey to identify eligible households, all households received new LLINs. Bͻkͻͻ net fan systems (one fan per member) were given to households in Group 1 and water filters were given to households in Group 2. At mid-point, Group 1 and 2 crossed over interventions. Households in Group 1 and 2 participated in fortnightly surveys on households' practices related to nets, fans and water filters, while households in Group 3 were surveyed only at screening, mid-point and study end. Entomological and weather data were collected throughout the study. Analysis took both 'per protocol' (PP) and 'intention to treat' (ITT) approaches. The mid- and end-point survey data from Group 1 and 2 were analysed using Firth logistic regressions. Fortnightly survey data from all groups were analysed using logistic regressions with random effects. RESULTS Provision of fans to households appeared to increase net use in this study. Although the increase in net use explained by fans was not significant in the primary analyses (ITT odds ratio 3.24, p > 0.01; PP odds ratio = 1.17, p > 0.01), it was significant in secondary PP analysis (odds ratio = 1.95, p < 0.01). Net use was high at screening and even higher after provision of new LLINs and with follow up. Fan use was 90-100% depending on the fortnightly visit. CONCLUSIONS This pilot study could not provide definitive evidence that fans increase net use. A larger study with additional statistical power is needed to assess this association across communities with diverse environmental and socio-demographic characteristics.
Collapse
Affiliation(s)
- Olivier J. T. Briët
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Joshua O. Yukich
- Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, USA
- Center for Applied Malaria Research and Evaluation, Tulane University, New Orleans, USA
| | - Constanze Pfeiffer
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | | | - Mulako S. Jaeger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Nitin Khanna
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | | | | | - Collins K. Ahorlu
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Joseph Keating
- Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, USA
- Center for Applied Malaria Research and Evaluation, Tulane University, New Orleans, USA
| |
Collapse
|
37
|
McBride CS. Genes and Odors Underlying the Recent Evolution of Mosquito Preference for Humans. Curr Biol 2016; 26:R41-6. [PMID: 26766234 DOI: 10.1016/j.cub.2015.11.032] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Mosquito species that specialize in biting humans are few but dangerous. They include the African malaria vectors Anopheles gambiae and Anopheles coluzzii, as well as Aedes aegypti, the cosmopolitan vector of dengue, chikungunya, and yellow fever. These mosquitoes have evolved a remarkable innate preference for human odor that helps them find and bite us. Here I review what is known about this important evolutionary adaptation, from its historical documentation to its chemical and molecular basis.
Collapse
Affiliation(s)
- Carolyn S McBride
- Princeton Neuroscience Institute, Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
| |
Collapse
|
38
|
Verhulst NO, Weldegergis BT, Menger D, Takken W. Attractiveness of volatiles from different body parts to the malaria mosquito Anopheles coluzzii is affected by deodorant compounds. Sci Rep 2016; 6:27141. [PMID: 27251017 PMCID: PMC4890431 DOI: 10.1038/srep27141] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 05/13/2016] [Indexed: 01/27/2023] Open
Abstract
Mosquitoes display biting preferences among different sites of the human body. In addition to height or convection currents, body odour may play a role in the selection of these biting sites. Previous studies have shown that skin emanations are important host-finding cues for mosquitoes. In this study, skin emanations were collected from armpits, hands and feet; the volatile profiles were analysed and tested for their attractiveness to the malaria mosquito Anopheles coluzzii. Skin emanations collected from armpits were less attractive to An. coluzzii compared to hands or/and feet. The difference may have been caused by deodorant residues, which were found in the armpit samples and not in those of hands and feet. In a subsequent experiment, volunteers were asked to avoid using skincare products for five days, and thereafter, no differences in attractiveness of the body parts to mosquitoes were found. The detected deodorant compound isopropyl tetradecanoate inhibited mosquito landings in a repellent bioassay. It is concluded that the volatiles emanated from different body parts induced comparable levels of attraction in mosquitoes, and that skincare products may reduce a person’s attractiveness to mosquitoes.
Collapse
Affiliation(s)
- Niels O Verhulst
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH Wageningen, the Netherlands
| | - Berhane T Weldegergis
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH Wageningen, the Netherlands
| | - David Menger
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH Wageningen, the Netherlands
| | - Willem Takken
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH Wageningen, the Netherlands
| |
Collapse
|
39
|
Orsborne J, DeRaedt Banks S, Hendy A, Gezan SA, Kaur H, Wilder-Smith A, Lindsay SW, Logan JG. Personal Protection of Permethrin-Treated Clothing against Aedes aegypti, the Vector of Dengue and Zika Virus, in the Laboratory. PLoS One 2016; 11:e0152805. [PMID: 27187593 PMCID: PMC4871372 DOI: 10.1371/journal.pone.0152805] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 03/18/2016] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The dengue and Zika viruses are primarily transmitted by Aedes aegypti mosquitoes, which are most active during day light hours and feed both in and outside of the household. Personal protection technologies such as insecticide-treated clothing could provide individual protection. Here we assessed the efficacy of permethrin-treated clothing on personal protection in the laboratory. METHODS The effect of washing on treated clothing, skin coverage and protection against resistant and susceptible Ae. aegypti was assessed using modified WHO arm-in-cage assays. Coverage was further assessed using free-flight room tests to investigate the protective efficacy of unwashed factory-dipped permethrin-treated clothing. Clothing was worn as full coverage (long sleeves and trousers) and partial coverage (short sleeves and shorts). Residual permethrin on the skin and its effect on mosquitoes was measured using modified WHO cone assays and quantified using high-pressure liquid chromatography (HPLC) analysis. RESULTS In the arm-in-cage assays, unwashed clothing reduced landing by 58.9% (95% CI 49.2-66.9) and biting by 28.5% (95% CI 22.5-34.0), but reduced to 18.5% (95% CI 14.7-22.3) and 11.1% (95% CI 8.5-13.8) respectively after 10 washes. Landing and biting for resistant and susceptible strains was not significantly different (p<0.05). In free-flight room tests, full coverage treated clothing reduced landing by 24.3% (95% CI 17.4-31.7) and biting by 91% (95% CI 82.2-95.9) with partial coverage reducing landing and biting by 26.4% (95% CI 20.3-31.2) and 49.3% (95% CI 42.1-59.1) respectively with coverage type having no significant difference on landing (p<0.05). Residual permethrin was present on the skin in low amounts (0.0041mg/cm2), but still produced a KD of >80% one hour after wearing treated clothing. CONCLUSION Whilst partially covering the body with permethrin-treated clothing provided some protection against biting, wearing treated clothing with long sleeves and trousers provided the highest form of protection. Washing treated clothing dramatically reduced protection provided. Permethrin-treated clothing could provide protection to individuals from Ae. aegypti that show permethrin resistance. Additionally, it could continue to provide protection even after the clothing has been worn. Field trials are urgently needed to determine whether clothing can protect against dengue and Zika.
Collapse
Affiliation(s)
- James Orsborne
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
- arctec, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Sarah DeRaedt Banks
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Adam Hendy
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Salvador A. Gezan
- SFRC, University of Florida, Gainesville, Florida, United States of America
| | - Harparkash Kaur
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Annelies Wilder-Smith
- Department of Global Health and Epidemiology, Umea University, Umea, Sweden
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Steve W. Lindsay
- School of Biological and Biomedical Sciences, Durham University, Durham, United Kingdom
| | - James G. Logan
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
- arctec, London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail:
| |
Collapse
|
40
|
Suh E, Choe DH, Saveer AM, Zwiebel LJ. Suboptimal Larval Habitats Modulate Oviposition of the Malaria Vector Mosquito Anopheles coluzzii. PLoS One 2016; 11:e0149800. [PMID: 26900947 PMCID: PMC4768836 DOI: 10.1371/journal.pone.0149800] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/04/2016] [Indexed: 01/08/2023] Open
Abstract
Selection of oviposition sites by gravid females is a critical behavioral step in the reproductive cycle of Anopheles coluzzii, which is one of the principal Afrotropical malaria vector mosquitoes. Several studies suggest this decision is mediated by semiochemicals associated with potential oviposition sites. To better understand the chemosensory basis of this behavior and identify compounds that can modulate oviposition, we examined the generally held hypothesis that suboptimal larval habitats give rise to semiochemicals that negatively influence the oviposition preference of gravid females. Dual-choice bioassays indicated that oviposition sites conditioned in this manner do indeed foster significant and concentration dependent aversive effects on the oviposition site selection of gravid females. Headspace analyses derived from aversive habitats consistently noted the presence of dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS) and 6-methyl-5-hepten-2-one (sulcatone) each of which unitarily affected An. coluzzii oviposition preference. Electrophysiological assays across the antennae, maxillary palp, and labellum of gravid An. coluzzii revealed differential responses to these semiochemicals. Taken together, these findings validate the hypothesis in question and suggest that suboptimal environments for An. coluzzii larval development results in the release of DMDS, DMTS and sulcatone that impact the response valence of gravid females.
Collapse
Affiliation(s)
- Eunho Suh
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Dong-Hwan Choe
- Department of Entomology, University of California, Riverside, California, United States of America
| | - Ahmed M. Saveer
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Laurence J. Zwiebel
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Pharmacology, Vanderbilt Brain Institute, Program in Developmental Biology, and Institutes of Chemical Biology and Global Health, Vanderbilt University Medical Center, Tennessee, United States of America
- * E-mail:
| |
Collapse
|
41
|
Menger DJ, Omusula P, Wouters K, Oketch C, Carreira AS, Durka M, Derycke JL, Loy DE, Hahn BH, Mukabana WR, Mweresa CK, van Loon JJA, Takken W, Hiscox A. Eave Screening and Push-Pull Tactics to Reduce House Entry by Vectors of Malaria. Am J Trop Med Hyg 2016; 94:868-78. [PMID: 26834195 DOI: 10.4269/ajtmh.15-0632] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 10/31/2015] [Indexed: 11/07/2022] Open
Abstract
Long-lasting insecticidal nets and indoor residual spraying have contributed to a decline in malaria over the last decade, but progress is threatened by the development of physiological and behavioral resistance of mosquitoes against insecticides. Acknowledging the need for alternative vector control tools, we quantified the effects of eave screening in combination with a push-pull system based on the simultaneous use of a repellent (push) and attractant-baited traps (pull). Field experiments in western Kenya showed that eave screening, whether used in combination with an attractant-baited trap or not, was highly effective in reducing house entry by malaria mosquitoes. The magnitude of the effect varied for different mosquito species and between two experiments, but the reduction in house entry was always considerable (between 61% and 99%). The use of outdoor, attractant-baited traps alone did not have a significant impact on mosquito house entry but the high number of mosquitoes trapped outdoors indicates that attractant-baited traps could be used for removal trapping, which would enhance outdoor as well as indoor protection against mosquito bites. As eave screening was effective by itself, addition of a repellent was of limited value. Nevertheless, repellents may play a role in reducing outdoor malaria transmission in the peridomestic area.
Collapse
Affiliation(s)
- David J Menger
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands; International Centre of Insect Physiology and Ecology, Nairobi, Kenya; Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal; Devan-Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Maia, Portugal; Devan Chemicals NV, Ronse, Belgium; Utexbel NV, Ronse, Belgium; Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Philemon Omusula
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands; International Centre of Insect Physiology and Ecology, Nairobi, Kenya; Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal; Devan-Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Maia, Portugal; Devan Chemicals NV, Ronse, Belgium; Utexbel NV, Ronse, Belgium; Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Karlijn Wouters
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands; International Centre of Insect Physiology and Ecology, Nairobi, Kenya; Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal; Devan-Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Maia, Portugal; Devan Chemicals NV, Ronse, Belgium; Utexbel NV, Ronse, Belgium; Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Charles Oketch
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands; International Centre of Insect Physiology and Ecology, Nairobi, Kenya; Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal; Devan-Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Maia, Portugal; Devan Chemicals NV, Ronse, Belgium; Utexbel NV, Ronse, Belgium; Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Ana S Carreira
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands; International Centre of Insect Physiology and Ecology, Nairobi, Kenya; Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal; Devan-Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Maia, Portugal; Devan Chemicals NV, Ronse, Belgium; Utexbel NV, Ronse, Belgium; Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Maxime Durka
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands; International Centre of Insect Physiology and Ecology, Nairobi, Kenya; Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal; Devan-Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Maia, Portugal; Devan Chemicals NV, Ronse, Belgium; Utexbel NV, Ronse, Belgium; Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Jean-Luc Derycke
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands; International Centre of Insect Physiology and Ecology, Nairobi, Kenya; Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal; Devan-Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Maia, Portugal; Devan Chemicals NV, Ronse, Belgium; Utexbel NV, Ronse, Belgium; Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Dorothy E Loy
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands; International Centre of Insect Physiology and Ecology, Nairobi, Kenya; Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal; Devan-Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Maia, Portugal; Devan Chemicals NV, Ronse, Belgium; Utexbel NV, Ronse, Belgium; Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Beatrice H Hahn
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands; International Centre of Insect Physiology and Ecology, Nairobi, Kenya; Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal; Devan-Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Maia, Portugal; Devan Chemicals NV, Ronse, Belgium; Utexbel NV, Ronse, Belgium; Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Wolfgang R Mukabana
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands; International Centre of Insect Physiology and Ecology, Nairobi, Kenya; Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal; Devan-Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Maia, Portugal; Devan Chemicals NV, Ronse, Belgium; Utexbel NV, Ronse, Belgium; Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Collins K Mweresa
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands; International Centre of Insect Physiology and Ecology, Nairobi, Kenya; Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal; Devan-Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Maia, Portugal; Devan Chemicals NV, Ronse, Belgium; Utexbel NV, Ronse, Belgium; Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Joop J A van Loon
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands; International Centre of Insect Physiology and Ecology, Nairobi, Kenya; Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal; Devan-Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Maia, Portugal; Devan Chemicals NV, Ronse, Belgium; Utexbel NV, Ronse, Belgium; Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Willem Takken
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands; International Centre of Insect Physiology and Ecology, Nairobi, Kenya; Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal; Devan-Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Maia, Portugal; Devan Chemicals NV, Ronse, Belgium; Utexbel NV, Ronse, Belgium; Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Alexandra Hiscox
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands; International Centre of Insect Physiology and Ecology, Nairobi, Kenya; Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal; Devan-Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Maia, Portugal; Devan Chemicals NV, Ronse, Belgium; Utexbel NV, Ronse, Belgium; Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| |
Collapse
|
42
|
Homan T, Maire N, Hiscox A, Di Pasquale A, Kiche I, Onoka K, Mweresa C, Mukabana WR, Ross A, Smith TA, Takken W. Spatially variable risk factors for malaria in a geographically heterogeneous landscape, western Kenya: an explorative study. Malar J 2016; 15:1. [PMID: 26729363 PMCID: PMC4700570 DOI: 10.1186/s12936-015-1044-1] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 12/09/2015] [Indexed: 11/17/2022] Open
Abstract
Background Large reductions in malaria transmission and mortality have been achieved over the last decade, and this has mainly been attributed to the scale-up of long-lasting insecticidal bed nets and indoor residual spraying with insecticides. Despite these gains considerable residual, spatially heterogeneous, transmission remains. To reduce transmission in these foci, researchers need to consider the local demographical, environmental and social context, and design an appropriate set of interventions. Exploring spatially variable risk factors for malaria can give insight into which human and environmental characteristics play important roles in sustaining malaria transmission. Methods On Rusinga Island, western Kenya, malaria infection was tested by rapid diagnostic tests during two cross-sectional surveys conducted 3 months apart in 3632 individuals from 790 households. For all households demographic data were collected by means of questionnaires. Environmental variables were derived using Quickbird satellite images. Analyses were performed on 81 project clusters constructed by a traveling salesman algorithm, each containing 50–51 households. A standard linear regression model was fitted containing multiple variables to determine how much of the spatial variation in malaria prevalence could be explained by the demographic and environmental data. Subsequently, a geographically-weighted regression (GWR) was performed assuming non-stationarity of risk factors. Special attention was taken to investigate the effect of residual spatial autocorrelation and local multicollinearity. Results Combining the data from both surveys, overall malaria prevalence was 24 %. Scan statistics revealed two clusters which had significantly elevated numbers of malaria cases compared to the background prevalence across the rest of the study area. A multivariable linear model including environmental and household factors revealed that higher socioeconomic status, outdoor occupation and population density were associated with increased malaria risk. The local GWR model improved the model fit considerably and the relationship of malaria with risk factors was found to vary spatially over the island; in different areas of the island socio-economic status, outdoor occupation and population density were found to be positively or negatively associated with malaria prevalence. Discussion Identification of risk factors for malaria that vary geographically can provide insight into the local epidemiology of malaria. Examining spatially variable relationships can be a helpful tool in exploring which set of targeted interventions could locally be implemented. Supplementary malaria control may be directed at areas, which are identified as at risk. For instance, areas with many people that work outdoors at night may need more focus in terms of vector control. Trial registration: Trialregister.nl NTR3496—SolarMal, registered on 20 June 2012
Collapse
Affiliation(s)
- Tobias Homan
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands.
| | - Nicolas Maire
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Alexandra Hiscox
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands.
| | - Aurelio Di Pasquale
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Ibrahim Kiche
- Department of Medical Entomology, International Centre of Insect Physiology and Ecology, Nairobi, Kenya.
| | - Kelvin Onoka
- Department of Medical Entomology, International Centre of Insect Physiology and Ecology, Nairobi, Kenya.
| | - Collins Mweresa
- Department of Medical Entomology, International Centre of Insect Physiology and Ecology, Nairobi, Kenya.
| | | | - Amanda Ross
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Thomas A Smith
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Willem Takken
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands.
| |
Collapse
|
43
|
Birget PLG, Koella JC. An Epidemiological Model of the Effects of Insecticide-Treated Bed Nets on Malaria Transmission. PLoS One 2015; 10:e0144173. [PMID: 26636568 PMCID: PMC4670222 DOI: 10.1371/journal.pone.0144173] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 11/13/2015] [Indexed: 11/21/2022] Open
Abstract
Insecticide-treated bed nets (ITNs) have become a central tool for malaria control because they provide personal and community-wide protection through their repellent and insecticidal properties. Here we propose a model that allows to assess the relative importance of those two effects in different epidemiological contexts and we show that these two levels of protection may oppose each other. On the one hand, repellency offers personal protection to the users of ITNs. The repellent action, however, is a two-edged sword, for it diverts infectious mosquitoes to non-users, thereby increasing their risk. Furthermore, with increasing ITN coverage, the personal protection effect of repellency decreases as mosquitoes are forced to perform multiple feeding attempts even on ITN users. On the other hand, the insecticidal property, which offers community-wide protection by killing mosquitoes, requires that mosquitoes contact the insecticide on the ITN and is thus counteracted by the repellency. Our model confirms that ITNs are an effective intervention method by reducing total malaria prevalence in the population, but that there is a conflict between personal protection, offered by repellency, and community-wide protection, which relies on the ITN’s insecticidal properties. Crucially, the model suggests that weak repellency allows disease elimination at lower ITN coverage levels.
Collapse
Affiliation(s)
| | - Jacob C. Koella
- Institute of Biology, Université de Neuchâtel, Neuchâtel, Switzerland
| |
Collapse
|
44
|
The chemical ecology of the fly. Curr Opin Neurobiol 2015; 34:95-102. [DOI: 10.1016/j.conb.2015.02.006] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 02/18/2015] [Accepted: 02/18/2015] [Indexed: 02/01/2023]
|
45
|
Samuel M, Oliver SV, Wood OR, Coetzee M, Brooke BD. Evaluation of the toxicity and repellence of an organic fatty acids mixture (C8910) against insecticide susceptible and resistant strains of the major malaria vector Anopheles funestus Giles (Diptera: Culicidae). Parasit Vectors 2015; 8:321. [PMID: 26062763 PMCID: PMC4464997 DOI: 10.1186/s13071-015-0930-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 06/02/2015] [Indexed: 11/10/2022] Open
Abstract
Background Malaria vector control relies principally on the use of insecticides, especially pyrethroids. Because of the increasing occurrence of insecticide resistance in target vector populations, the development of new insecticides, particularly those with novel modes of action, is particularly important, especially in terms of managing insecticide resistance. The C8910 formulation is a patented mixture of compounds comprising straight-chain octanoic, nonanoic and decanoic saturated fatty acids. This compound has demonstrated toxic and repellent effects against several arthropod species. The aims of this study were to measure the insecticidal effects of C8910 against an insecticide susceptible (FANG) and a pyrethroid resistant (FUMOZ-R) laboratory strain of An. funestus as well as against wild-caught An. funestus material from Zambia (ZamF), and to investigate the repellent effects of two formulations of C8910 against these strains. Methods Toxicity against adult females was assessed using a range of concentrations based on the CDC bottle bioassay method and repellence of three different C8910 formulations was assessed using standard choice-chamber bioassays. Results C8910 proved equally toxic to adult females of the FUMOZ-R and FANG laboratory strains, as well as to adult females of the wild-caught (ZamF) sample. None of the C8910 formulations tested gave any conclusive indication of repellence against any of the strains. Conclusion C8910 is equally effective as an adulticide against pyrethroid resistant and insecticide susceptible An. funestus. However, the formulations tested did not show any consistent repellence against laboratory reared and wild-caught female samples of this species. Nevertheless, C8910 shows potential as an adulticide that can be used for malaria vector control, particularly in those instances where insecticide resistance management is required.
Collapse
Affiliation(s)
- Michael Samuel
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. .,Centre for Opportunistic, Tropical & Hospital Infections, National Institute for Communicable Diseases, Johannesburg, South Africa.
| | - Shüné V Oliver
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. .,Centre for Opportunistic, Tropical & Hospital Infections, National Institute for Communicable Diseases, Johannesburg, South Africa.
| | - Oliver R Wood
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. .,Centre for Opportunistic, Tropical & Hospital Infections, National Institute for Communicable Diseases, Johannesburg, South Africa.
| | - Maureen Coetzee
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. .,Centre for Opportunistic, Tropical & Hospital Infections, National Institute for Communicable Diseases, Johannesburg, South Africa.
| | - Basil D Brooke
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. .,Centre for Opportunistic, Tropical & Hospital Infections, National Institute for Communicable Diseases, Johannesburg, South Africa.
| |
Collapse
|
46
|
van Loon JJA, Smallegange RC, Bukovinszkiné-Kiss G, Jacobs F, De Rijk M, Mukabana WR, Verhulst NO, Menger DJ, Takken W. Mosquito Attraction: Crucial Role of Carbon Dioxide in Formulation of a Five-Component Blend of Human-Derived Volatiles. J Chem Ecol 2015; 41:567-73. [PMID: 26026743 PMCID: PMC4463982 DOI: 10.1007/s10886-015-0587-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 04/28/2015] [Accepted: 05/01/2015] [Indexed: 01/19/2023]
Abstract
Behavioral responses of the malaria mosquito Anopheles coluzzii (An. gambiae sensu stricto molecular 'M form') to an expanded blend of human-derived volatiles were assessed in a dual-port olfactometer. A previously documented attractive three-component blend consisting of NH3, (S)-lactic acid, and tetradecanoic acid served as the basis for expansion. Adding 4.5% CO2 to the basic blend significantly enhanced its attractiveness. Expansion of the blend with four human-derived C4-volatiles was then assessed, both with and without CO2. Only when CO2 was offered simultaneously, did addition of a specific concentration of 3-methyl-1-butanol or 3-methyl-butanoic acid significantly enhance attraction. The functional group at the terminal C of the 3-methyl-substituted C4 compounds influenced behavioral effectiveness. In the absence of CO2, addition of three concentrations of butan-1-amine caused inhibition when added to the basic blend. In contrast, when CO2 was added, butan-1-amine added to the basic blend strongly enhanced attraction at all five concentrations tested, the lowest being 100,000 times diluted. The reversal of inhibition to attraction by adding CO2 is unique in the class Insecta. We subsequently augmented the three-component basic blend by adding both butan-1-amine and 3-methyl-1-butanol and optimizing their concentrations in the presence of CO2 in order to significantly enhance the attractiveness to An. coluzzii compared to the three- and four-component blends. This novel blend holds potential to enhance malaria vector control based on behavioral disruption.
Collapse
Affiliation(s)
- Joop J A van Loon
- Laboratory of Entomology, Wageningen University, P.O. Box 16, 6700 AA, Wageningen, The Netherlands,
| | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Menger DJ, Omusula P, Holdinga M, Homan T, Carreira AS, Vandendaele P, Derycke JL, Mweresa CK, Mukabana WR, van Loon JJA, Takken W. Field evaluation of a push-pull system to reduce malaria transmission. PLoS One 2015; 10:e0123415. [PMID: 25923114 PMCID: PMC4414508 DOI: 10.1371/journal.pone.0123415] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 02/18/2015] [Indexed: 11/24/2022] Open
Abstract
Malaria continues to place a disease burden on millions of people throughout the tropics, especially in sub-Saharan Africa. Although efforts to control mosquito populations and reduce human-vector contact, such as long-lasting insecticidal nets and indoor residual spraying, have led to significant decreases in malaria incidence, further progress is now threatened by the widespread development of physiological and behavioural insecticide-resistance as well as changes in the composition of vector populations. A mosquito-directed push-pull system based on the simultaneous use of attractive and repellent volatiles offers a complementary tool to existing vector-control methods. In this study, the combination of a trap baited with a five-compound attractant and a strip of net-fabric impregnated with micro-encapsulated repellent and placed in the eaves of houses, was tested in a malaria-endemic village in western Kenya. Using the repellent delta-undecalactone, mosquito house entry was reduced by more than 50%, while the traps caught high numbers of outdoor flying mosquitoes. Model simulations predict that, assuming area-wide coverage, the addition of such a push-pull system to existing prevention efforts will result in up to 20-fold reductions in the entomological inoculation rate. Reductions of such magnitude are also predicted when mosquitoes exhibit a high resistance against insecticides. We conclude that a push-pull system based on non-toxic volatiles provides an important addition to existing strategies for malaria prevention.
Collapse
Affiliation(s)
- David J. Menger
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH, Wageningen, The Netherlands
- * E-mail:
| | - Philemon Omusula
- International Centre of Insect Physiology and Ecology, P.O. Box 30772, GPO Nairobi, Kenya
| | - Maarten Holdinga
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH, Wageningen, The Netherlands
| | - Tobias Homan
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH, Wageningen, The Netherlands
| | - Ana S. Carreira
- CIEPQPF, Department of Chemical Engineering, University of Coimbra, Rua Sílvio Lima, 3030–790, Coimbra, Portugal
- Devan—Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Rua Eng. Frederico Ulrich, 2650, 4470–605, Maia, Portugal
| | | | | | - Collins K. Mweresa
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH, Wageningen, The Netherlands
- International Centre of Insect Physiology and Ecology, P.O. Box 30772, GPO Nairobi, Kenya
| | - Wolfgang Richard Mukabana
- International Centre of Insect Physiology and Ecology, P.O. Box 30772, GPO Nairobi, Kenya
- School of Biological Sciences, University of Nairobi, P.O. Box 30197–00100, GPO Nairobi, Kenya
| | - Joop J. A. van Loon
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH, Wageningen, The Netherlands
| | - Willem Takken
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH, Wageningen, The Netherlands
| |
Collapse
|
48
|
Busula AO, Takken W, Loy DE, Hahn BH, Mukabana WR, Verhulst NO. Mosquito host preferences affect their response to synthetic and natural odour blends. Malar J 2015; 14:133. [PMID: 25889954 PMCID: PMC4381365 DOI: 10.1186/s12936-015-0635-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 03/01/2015] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND The anthropophilic malaria mosquito Anopheles gambiae sensu stricto (hereafter termed Anopheles gambiae) primarily takes blood meals from humans, whereas its close sibling Anopheles arabiensis is more opportunistic. Previous studies have identified several compounds that play a critical role in the odour-mediated behaviour of An. gambiae. This study determined the effect of natural and synthetic odour blends on mosquitoes with different host preferences to better understand the host-seeking behaviour of mosquitoes and the potential of synthetic odour blends for standardized monitoring. METHODS Odour blends were initially tested for their attractiveness to An. gambiae and An. arabiensis in a semi-field system with MM-X traps baited with natural and synthetic odours. Natural host odours were collected from humans, cows and chickens. The synthetic odour blends consisted of three or five previously identified compounds released with carbon dioxide. These studies were continued under natural conditions where odour blends were tested outdoors to determine their effect on species with different host preferences. RESULTS In the semi-field experiments, human odour attracted significantly higher numbers of both mosquito species. However, An. arabiensis was also attracted to cow and chicken odours, which confirms its opportunistic behaviour. A five-component synthetic blend was highly attractive to both mosquito species. In the field, the synthetic odour blend caught significantly more An. funestus than traps baited with human odour, while no difference was found for An. arabiensis. Catches of An. arabiensis and Culex spp. contained large numbers of blood-fed mosquitoes, mostly from cows, which indicates that these mosquitoes had fed outdoors. CONCLUSIONS Different odour baits elicit varying responses among mosquito species. Synthetic odour blends are highly effective for trapping mosquitoes; however, not all mosquitoes respond equally to the same odour blend. Combining fermenting molasses with synthetic blends in a trap represents the most effective tool to catch blood-fed mosquitoes outside houses, which is essential for understanding outdoor malaria transmission.
Collapse
Affiliation(s)
- Annette O Busula
- International Centre of Insect Physiology and Ecology, PO Box 30772-00100 GPO, Nairobi, Kenya. .,Laboratory of Entomology, Wageningen University, PO Box 8031, 6700 EH, Wageningen, The Netherlands.
| | - Willem Takken
- Laboratory of Entomology, Wageningen University, PO Box 8031, 6700 EH, Wageningen, The Netherlands.
| | - Dorothy E Loy
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, PA, 19104-6076, USA.
| | - Beatrice H Hahn
- Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, PA, 19104-6076, USA.
| | - Wolfgang R Mukabana
- International Centre of Insect Physiology and Ecology, PO Box 30772-00100 GPO, Nairobi, Kenya. .,School of Biological Sciences, University of Nairobi, PO Box 30197-00100 GPO, Nairobi, Kenya.
| | - Niels O Verhulst
- Laboratory of Entomology, Wageningen University, PO Box 8031, 6700 EH, Wageningen, The Netherlands.
| |
Collapse
|
49
|
Waiting with bated breath: opportunistic orientation to human odor in the malaria mosquito, Anopheles gambiae, is modulated by minute changes in carbon dioxide concentration. J Chem Ecol 2015; 41:59-66. [PMID: 25572756 DOI: 10.1007/s10886-014-0542-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/24/2014] [Accepted: 12/05/2014] [Indexed: 10/24/2022]
Abstract
Females of the malaria mosquito, Anopheles gambiae, predominantly obtain blood meals within human dwellings. Being highly anthropophilic, human skin odor offers a reliable, host-specific cue, but the challenge posed by pervasive human odor found indoors from used clothing, bedding etc. remains unclear. Anopheles gambiae spends much of its adult life indoors, constantly exposed to human odor even when dwellings are unoccupied. In landing assays, we found that female mosquitoes respond very weakly to human skin odor alone, suggesting that, alone, it is an ineffective landing cue. Landing, however, was dramatically increased by addition of carbon dioxide at a range of concentrations above ambient. Indeed, this effect was seen even when carbon dioxide was just 0.015% above ambient within the assay cage. The synergistic effect of added carbon dioxide quickly waned, thereby facilitating a highly adaptive "sit-and-wait" ambush strategy, wherein females ignore persistent human odor until a living human is present. Unexpectedly, landing rates in the presence of added carbon dioxide were almost as robust during daytime, when An. gambiae has previously been assumed inactive, possibly facilitating opportunistic feeding at times of day when human dwellings are occupied intermittently. We suggest earlier studies that showed strong upwind flight behavior toward human odor alone could, in fact, have been demonstrating orientation toward a human dwelling rather than toward a living human. This new interpretation of how human odors mediate upwind orientation and landing in An. gambiae is discussed.
Collapse
|
50
|
Sparks JT, Bohbot JD, Dickens JC. Olfactory Disruption. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 130:81-108. [DOI: 10.1016/bs.pmbts.2014.11.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
|