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Bakker JW, Loy DE, Takken W, Hahn BH, Verhulst NO. Attraction of mosquitoes to primate odours and implications for zoonotic Plasmodium transmission. Med Vet Entomol 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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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
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Möhlmann TWR, Bekendam AM, van Kemenade I, Wennergren U, Favia G, Takken W, Koenraadt CJM. Latitudinal diversity of biting midge species within the Obsoletus group across three habitats in Europe. Med Vet Entomol 2019; 33:420-426. [PMID: 31033029 PMCID: PMC6849825 DOI: 10.1111/mve.12379] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 03/11/2019] [Accepted: 03/21/2019] [Indexed: 05/22/2023]
Abstract
Culicoides species from the Obsoletus group are important vectors of bluetongue and Schmallenberg virus. This group consists of several species that cannot easily be identified using morphological characteristics. Therefore, limited information is available about their distribution and habitat preferences. In this study, we aimed to elucidate the species composition of the Obsoletus group in three habitat types at climatically different latitudes across Europe. Traps were placed in three habitat types in three countries at different latitudes. After DNA extraction, biting midges were identified using PCR and gel electrophoresis. Extraction of DNA using Chelex proved to be a cost and time efficient method for species identification. A latitudinal effect on the relative abundance of species from the Obsoletus group was found. Species composition was unique for most country-habitat combinations. The majority of biting midges were either C. obsoletus s.s. or C. scoticus, and both species were found at all latitudes and habitats. Their wide distribution and their high abundance at livestock farms make these species likely candidates for rapid farm-to-farm transmission of pathogens throughout Europe. Our results emphasize the need to differentiate Obsoletus group species to better understand their ecology and contribution to pathogen transmission.
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Affiliation(s)
- T. W. R. Möhlmann
- Laboratory of EntomologyWageningen University and ResearchWageningenThe Netherlands
- IFM Theory and ModellingLinköping UniversityLinköpingSweden
| | - A. M. Bekendam
- Laboratory of EntomologyWageningen University and ResearchWageningenThe Netherlands
| | - I. van Kemenade
- Laboratory of EntomologyWageningen University and ResearchWageningenThe Netherlands
| | - U. Wennergren
- IFM Theory and ModellingLinköping UniversityLinköpingSweden
| | - G. Favia
- School of Biosciences and Veterinary MedicineUniversity of CamerinoCamerinoItaly
| | - W. Takken
- Laboratory of EntomologyWageningen University and ResearchWageningenThe Netherlands
| | - C. J. M. Koenraadt
- Laboratory of EntomologyWageningen University and ResearchWageningenThe Netherlands
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Athrey G, Cosme LV, Popkin-Hall Z, Pathikonda S, Takken W, Slotman MA. Chemosensory gene expression in olfactory organs of the anthropophilic Anopheles coluzzii and zoophilic Anopheles quadriannulatus. BMC Genomics 2017; 18:751. [PMID: 28938869 PMCID: PMC5610455 DOI: 10.1186/s12864-017-4122-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 09/06/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Anopheles (An.) coluzzii, one of Africa's primary malaria vectors, is highly anthropophilic. This human host preference contributes greatly to its ability to transmit malaria. In contrast, the closely related An. quadriannulatus prefers to feed on bovids and is not thought to contribute to malaria transmission. The diverged preference for host odor profiles between these sibling species is likely reflected in chemosensory gene expression levels in the olfactory organs. Therefore, we compared the transcriptomes of the antennae and maxillary palps between An. coluzzii and An. quadriannulatus, focusing on the major chemosensory gene families. RESULTS While chemosensory gene expression is strongly correlated between the two species, various chemosensory genes show significantly enhanced expression in one of the species. In the antennae of An. coluzzii the expression of six olfactory receptors (Ors) and seven ionotropic receptors (Irs) is considerably enhanced, whereas 11 Ors and 3 Irs are upregulated in An. quadriannulatus. In the maxillary palps, leaving aside Irs with very low level of expression, one Ir is strongly enhanced in each species. In addition, we find divergence in odorant binding protein (Obp) gene expression, with several highly expressed Obps being enhanced in the antennae and palps of An. coluzzii. Finally, the expression of several gustatory receptors (Grs) in the palps appears to be species-specific, including a homolog of a sugar-sensing Drosophila Gr. CONCLUSIONS A considerable number of Ors and Irs are differentially expressed between these two closely related species with diverging host preference. These chemosensory genes could play a role in the human host preference of the malaria vector An. coluzzii. Additionally, divergence in Obp expression between the two species suggests a possible role of these odor carrier proteins in determining host preference. Finally, divergence in chemosensory expression in the palps may point towards a possible role for the maxillary palps in host differentiation.
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Affiliation(s)
- G. Athrey
- Department of Poultry Science, Texas A&M University, College Station, TX USA
| | - L. V. Cosme
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT USA
| | - Z. Popkin-Hall
- Department of Entomology, Texas A&M University, College Station, TX 77845 USA
| | - S. Pathikonda
- Department of Entomology, Texas A&M University, College Station, TX 77845 USA
| | - W. Takken
- Laboratory of Entomology, Wageningen University, Wageningen, The Netherlands
| | - M. A. Slotman
- Department of Entomology, Texas A&M University, College Station, TX 77845 USA
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VAN Duijvendijk G, Gort G, Sprong H, Takken W. Behavioural responses of Ixodes ricinus nymphs to carbon dioxide and rodent odour. Med Vet Entomol 2017; 31:220-223. [PMID: 27966215 DOI: 10.1111/mve.12214] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/21/2016] [Accepted: 09/22/2016] [Indexed: 06/06/2023]
Abstract
Many haematophagous ectoparasites use carbon dioxide (CO2 ) and host odour to detect and locate their hosts. The tick Ixodes ricinus (Linnaeus) (Ixodida: Ixodidae) walks only small distances and quests in vegetation until it encounters a host. The differential effects of CO2 and host odour on the host-finding behaviour of I. ricinus have, however, never been clarified and hence represent the subject of this study. The effects of CO2 and odour from bank voles on the activation and attraction of I. ricinus nymphs were analysed in a Y-tube olfactometer. Carbon dioxide evoked a response in the absence and presence of host odour, but did not attract nymphs. Host odour, however, did not evoke a response but did attract nymphs in the absence and presence of CO2 . The current results show that CO2 is an activator, but not an attractant, and that host odour is an attractant, but not an activator, of I. ricinus nymphs, and provide ecological insights into the host-finding behaviour of I. ricinus.
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Affiliation(s)
- G VAN Duijvendijk
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, the Netherlands
| | - G Gort
- Mathematical and Statistical Methods Division, Wageningen University and Research Centre, Wageningen, the Netherlands
| | - H Sprong
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, the Netherlands
- Laboratory for Zoonosis and Environmental Microbiology, National Institute for Public Health and Environment [Rijksinstituut voor Volksgezondheit en Milieu (RIVM)], Bilthoven, the Netherlands
| | - W Takken
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, the Netherlands
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Knols BGJ, Takken W, Cork A, Jong RD. Odour-mediated, host-seeking behaviour of Anopheles mosquitoes: a new approach. Annals of Tropical Medicine & Parasitology 2016. [DOI: 10.1080/00034983.1997.11813250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Takken W, Knols BGJ, Otten H. Interactions between physical and olfactory cues in the host-seeking behaviour of mosquitoes: the role of relative humidity. Annals of Tropical Medicine & Parasitology 2016. [DOI: 10.1080/00034983.1997.11813251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Turley AP, Smallegange RC, Takken W, Zalucki MP, O'Neill SL, McGraw EA. Wolbachia infection does not alter attraction of the mosquito Aedes (Stegomyia) aegypti to human odours. Med Vet Entomol 2014; 28:457-460. [PMID: 24797695 DOI: 10.1111/mve.12063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/27/2014] [Accepted: 01/31/2014] [Indexed: 06/03/2023]
Abstract
The insect endosymbiont Wolbachia pipientis (Rickettsiales: Rickettsiaceae) is undergoing field trials around the world to determine if it can reduce transmission of dengue virus from the mosquito Stegomyia aegypti to humans. Two different Wolbachia strains have been released to date. The primary effect of the wMel strain is pathogen protection whereby infection with the symbiont limits replication of dengue virus inside the mosquito. A second strain, wMelPop, induces pathogen protection, reduces the adult mosquito lifespan and decreases blood feeding success in mosquitoes after 15 days of age. Here we test whether Wolbachia infection affects mosquito attraction to host odours in adults aged 5 and 15 days. We found no evidence of reduced odour attraction of mosquitoes, even for those infected with the more virulent wMelPop. This bodes well for fitness and competitiveness in the field given that the mosquitoes must find hosts to reproduce for the biocontrol method to succeed.
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Affiliation(s)
- A P Turley
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia; School of Biological Sciences, The University of Queensland, St Lucia, Queensland, Australia
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Menger DJ, Van Loon JJA, Takken W. Assessing the efficacy of candidate mosquito repellents against the background of an attractive source that mimics a human host. Med Vet Entomol 2014; 28:407-413. [PMID: 24797537 DOI: 10.1111/mve.12061] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 02/11/2014] [Accepted: 02/17/2014] [Indexed: 06/03/2023]
Abstract
Mosquito repellents are used around the globe to protect against nuisance biting and disease-transmitting mosquitoes. Recently, there has been renewed interest in the development of repellents as tools to control the transmission of mosquito-borne diseases. We present a new bioassay for the accurate assessment of candidate repellent compounds, using a synthetic odour that mimics the odour blend released by human skin. Using DEET (N,N-diethyl-meta-toluamide) and PMD (p-menthane-3,8-diol) as reference compounds, nine candidate repellents were tested, of which five showed significant repellency to the malaria mosquito Anopheles gambiae sensu stricto (Diptera: Culicidae). These included: 2-nonanone; 6-methyl-5-hepten-2-one; linalool; δ-decalactone, and δ-undecalactone. The lactones were also tested on the yellow fever mosquito Aedes aegypti (Stegomyia aegypti) (Diptera: Culicidae), against which they showed similar degrees of repellency. We conclude that the lactones are highly promising repellents, particularly because these compounds are pleasant-smelling, natural products that are also present in human food sources.
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Affiliation(s)
- D J Menger
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, the Netherlands
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Cochez C, Heyman P, Heylen D, Fonville M, Hengeveld P, Takken W, Simons L, Sprong H. The Presence of Borrelia miyamotoi, A Relapsing Fever Spirochaete, in Questing Ixodes ricinus in Belgium and in The Netherlands. Zoonoses Public Health 2014; 62:331-3. [PMID: 25212814 DOI: 10.1111/zph.12154] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Indexed: 11/28/2022]
Abstract
Borrelia miyamotoi is a tick-borne bacterium that may cause relapsing fever in humans. As this pathogen has been discovered in Europe only recently, only little is known about its local impact on human health and its spatial distribution. In this study, we show the results of PCR screenings for B. miyamotoi in flagged Ixodes ricinus from Belgium and the Netherlands. B. miyamotoi was detected in nine of thirteen, and three of five locations from the Netherlands and Belgium, respectively. These outcomes indicate that B. miyamotoi is more spread than previously thought. The mean infection rate B. miyamotoi was 1.14% for Belgium and 3.84% for the Netherlands.
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Affiliation(s)
- C Cochez
- Research Laboratory for Vector-Borne Diseases, Queen Astrid Military Hospital, Brussels, Belgium
| | - P Heyman
- Research Laboratory for Vector-Borne Diseases, Queen Astrid Military Hospital, Brussels, Belgium
| | - D Heylen
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Antwerp, Belgium
| | - M Fonville
- Laboratory for Zoonoses and Environmental Microbiology, National Institute for Public Health and Environment (RIVM), Bilthoven, The Netherlands
| | - P Hengeveld
- Laboratory for Zoonoses and Environmental Microbiology, National Institute for Public Health and Environment (RIVM), Bilthoven, The Netherlands
| | - W Takken
- Laboratory of Entomology, Wageningen University, Wageningen, The Netherlands
| | - L Simons
- Research Laboratory for Vector-Borne Diseases, Queen Astrid Military Hospital, Brussels, Belgium
| | - H Sprong
- Laboratory for Zoonoses and Environmental Microbiology, National Institute for Public Health and Environment (RIVM), Bilthoven, The Netherlands
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Pacilly FCA, Benning ME, Jacobs F, Leidekker J, Sprong H, Van Wieren SE, Takken W. Blood feeding on large grazers affects the transmission of Borrelia burgdorferi sensu lato by Ixodes ricinus. Ticks Tick Borne Dis 2014; 5:810-7. [PMID: 25113977 DOI: 10.1016/j.ttbdis.2014.06.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 05/28/2014] [Accepted: 06/12/2014] [Indexed: 12/11/2022]
Abstract
The presence of Ixodes ricinus and their associated Borrelia infections on large grazers was investigated. Carcases of freshly shot red deer, mouflon and wild boar were examined for the presence of any stage of I. ricinus. Questing ticks were collected from locations where red deer and wild boar are known to occur. Presence of Borrelia burgdorferi s.l. DNA was examined in a fraction of the collected ticks. Larvae, nymphs and adult ticks were found on the three large grazers. Red deer had the highest tick burden, with many of the nymphs and adult females attached for engorgement. Most larvae had not attached. The mean number of ticks on the animals varied from 13 to 67. Ticks were highly aggregated amongst the animals: some animals had no ticks, while others had high numbers. Larvae and nymphs were mostly found on the ears, while adult ticks were attached to the axillae. The Borrelia infection rate of questing nymphs was 8.5%. Unengorged wandering nymphs on deer had a Borrelia infection rate of 12.5%, while only 0.9% of feeding nymphs carried a Borrelia infection. The infection rate of unengorged adult male ticks was 4.5%, and that of feeding female ticks was 0.7%. The data suggest that ticks feeding on red deer and wild boar lose their Borrelia infections. The implications of the results are discussed with respect to Borrelia epidemiology and maintenance of a Borrelia reservoir as well as the role of reproductive hosts for Ixodes ricinus.
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Affiliation(s)
- F C A Pacilly
- Laboratory of Entomology, Wageningen University, PO Box 8031, 6700 EH Wageningen, The Netherlands
| | - M E Benning
- Resource Ecology Group, Wageningen University, Droevendaalsesteeg 3a, 6708 PB Wageningen, The Netherlands
| | - F Jacobs
- Laboratory of Entomology, Wageningen University, PO Box 8031, 6700 EH Wageningen, The Netherlands
| | - J Leidekker
- National Park de Hoge Veluwe, Apeldoornseweg 250, 7351 TA Hoenderloo, The Netherlands
| | - H Sprong
- Laboratory of Entomology, Wageningen University, PO Box 8031, 6700 EH Wageningen, The Netherlands; Laboratory for Zoonoses and Environmental Microbiology, National Institute for Public Health and Environment (RIVM), Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven, The Netherlands
| | - S E Van Wieren
- Resource Ecology Group, Wageningen University, Droevendaalsesteeg 3a, 6708 PB Wageningen, The Netherlands
| | - W Takken
- Laboratory of Entomology, Wageningen University, PO Box 8031, 6700 EH Wageningen, The Netherlands.
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Pates HV, Curtis CF, Takken W. Hybridization studies to modify the host preference of Anopheles gambiae. Med Vet Entomol 2014; 28 Suppl 1:68-74. [PMID: 25171608 DOI: 10.1111/mve.12070] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 02/18/2014] [Accepted: 03/04/2014] [Indexed: 06/03/2023]
Abstract
A strategy to decrease the vector competence of Anopheles gambiae sensu stricto (Diptera: Culicidae), the most efficient malaria vector in Africa, may consist of exploiting the genes involved in zoophily. Crossing and backcrossing experiments were performed between An. gambiae s.s. and the zoophilic sibling species Anopheles quadriannulatus. Mosquito strains were tested in a dual-choice olfactometer to investigate their responses to cow odour. Totals of 12% of An. gambiae s.s. and 59% of An. quadriannulatus selected the port with the cow odour. Crosses and backcrosses did not show a significant preference for the cow-baited port. The results indicated that anthropophilic behaviour in An. gambiae s.s. is a dominant or partially dominant trait, which, in conjunction with the unstable zoophilic behaviour observed in An. quadriannulatus, poses a serious obstacle to plans to decrease vector competence by modifying the anthropophilic trait.
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Affiliation(s)
- H V Pates
- Laboratory of Entomology, Wageningen University, Wageningen, the Netherlands; Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, U.K
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Qiu YT, Smallegange RC, VAN Loon JJA, Takken W. Behavioural responses of Anopheles gambiae sensu stricto to components of human breath, sweat and urine depend on mixture composition and concentration. Med Vet Entomol 2011; 25:247-55. [PMID: 21108650 DOI: 10.1111/j.1365-2915.2010.00924.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Host-seeking behaviour of the anthropophilic malaria vector Anopheles gambiae sensu stricto (Diptera: Culicidae) is mediated predominantly by olfactory cues. Several hundreds of odour components have been identified from human emanations, but only a few have been proven to act as attractants or synergists in the host-seeking behaviour of female An. gambiae. In previous work, aromatics, alcohols and ketones in human odours were found to elicit electrophysiological activity in antennal olfactory neurons of female An. gambiae. However, the behavioural effects of these compounds have not been investigated. In this study, behavioural responses of female An. gambiae to components of human breath, urine and sweat at a series of concentrations, or a single concentration in the case of acetone, were examined in combination with ammonia and L-lactic acid in a dual-choice olfactometer. The results showed that at specific concentrations 4-ethylphenol, indole, 3-methyl-1-butanol and two ketones inhibited the attractive effect of a mixture of ammonia and lactic acid. Acetone on its own was not attractive; however, when combined with lactic acid, the binary mixture was attractive. When combined with ammonia, acetone inhibited the attractiveness exerted by ammonia alone. Dodecanol and dimethyldisulphide did not affect the attraction exerted by ammonia and lactic acid at any of the concentrations tested. By contrast, a human-specific armpit odour, 7-octenoic acid, augmented the attraction exerted by the combination of ammonia and lactic acid at a specific dosage.
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Affiliation(s)
- Y T Qiu
- Laboratory of Entomology, Wageningen University, Wageningen, the Netherlands.
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Hiwat H, De Rijk M, Andriessen R, Koenraadt CJM, Takken W. Evaluation of methods for sampling the malaria vector Anopheles darlingi (Diptera, Culicidae) in Suriname and the relation with its biting behavior. J Med Entomol 2011; 48:1039-1046. [PMID: 21936323 DOI: 10.1603/me10245] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The effectiveness of CO2-baited and human-baited mosquito traps for the sampling of Anopheles darlingi Root was evaluated and compared with human landing collections in Suriname. Biting preferences of this mosquito on a human host were studied and related to trapping data. Traps used were the Centers for Disease Control and Prevention Miniature Light trap, the BG Sentinel mosquito trap, the Mosquito Magnet Liberty Plus mosquito trap (MM-Plus), and a custom-designed trap. Carbon dioxide and humans protected by a bed net were used as bait in the studies. The number of An. darlingi collected was greater with human landing collections than with all other collection methods. An. darlingi did not show a preference for protected humans over CO2 bait. The BG Sentinel mosquito trap with CO2 or human odor as bait and the MM-Plus proved the best alternative sampling tools for An. darlingi. The BG Sentinel mosquito trap with CO2 or human odor as bait was also very efficient at collecting Culex spp. In a field study on biting preferences of wild An. darlingi, the females showed directional biting behavior (P < 0.001), with a majority of females (93.3%) biting the lower legs and feet when approaching a seated human host. Higher efficiency of the closer-to-the-ground collecting MM-Plus and BG Sentinel mosquito trap when compared with the other trapping methods may be a result of a possible preference of this mosquito species for low-level biting. It is concluded that odor-baited sampling systems can reliably collect An. darlingi, but the odor bait needs to be improved, for instance, by including host-specific volatiles, to match live human baits.
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Affiliation(s)
- H Hiwat
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH, The Netherlands.
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Sprong H, Tijsse-Klasen E, Langelaar M, De Bruin A, Fonville M, Gassner F, Takken W, Van Wieren S, Nijhof A, Jongejan F, Maassen CBM, Scholte EJ, Hovius JW, Emil Hovius K, Špitalská E, Van Duynhoven YT. Prevalence of Coxiella Burnetii in Ticks After a Large Outbreak of Q Fever. Zoonoses Public Health 2011; 59:69-75. [DOI: 10.1111/j.1863-2378.2011.01421.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Imbahale SS, Fillinger U, Githeko A, Mukabana WR, Takken W. An exploratory survey of malaria prevalence and people's knowledge, attitudes and practices of mosquito larval source management for malaria control in western Kenya. Acta Trop 2010; 115:248-56. [PMID: 20399739 DOI: 10.1016/j.actatropica.2010.04.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 04/04/2010] [Accepted: 04/08/2010] [Indexed: 11/19/2022]
Abstract
A large proportion of mosquito larval habitats in urban and rural communities in sub-Saharan Africa are man-made. Therefore, community-based larval source management (LSM) could make a significant contribution to malaria control in an integrated vector management approach. Here we implemented an exploratory study to assess malaria prevalence and people's knowledge, attitudes and practices on malaria transmission, its control and the importance of man-made aquatic habitats for the development of disease vectors in one peri-urban lowland and two rural highland communities in western Kenya. We implemented monthly cross-sectional malaria surveys and administered a semi-structured questionnaire in 90 households, i.e. 30 households in each locality. Malaria prevalence was moderate (3.2-6.5%) in all sites. Nevertheless, residents perceived malaria as their major health risk. Thirty-two percent (29/90) of all respondents did not know that mosquitoes are responsible for the transmission of malaria. Over two-thirds (69/90) of the respondents said that mosquito breeding site could be found close to their homes but correct knowledge of habitat characteristics was poor. Over one-third (26/67) believed that immature mosquitoes develop in vegetation. Man-made pools, drainage channels and burrow pits were rarely mentioned. After explaining where mosquito larvae develop, 56% (50/90) felt that these sites were important for their livelihood. Peri-urban residents knew more about mosquitoes' role in malaria transmission, could more frequently describe the larval stages and their breeding habitats, and were more likely to use bed nets even though malaria prevalence was only half of what was found in the rural highland sites (p<0.05). This was independent of their education level or socio-economic status. Hence rural communities are more vulnerable to malaria infection, thus calling for additional methods to complement personal protection measures for vector control. Larval source management was the most frequently mentioned (30%) tool for malaria control but was only practiced by 2 out of 90 respondents. Targeting the larval stages of malaria vectors is an underutilized malaria prevention measure. Sustainable elimination or rendering of such habitats unsuitable for larval development needs horizontally organized, community-based programs that take people's needs into account. Innovative, community-based training programs need to be developed to increase people's awareness of man-made vector breeding sites and acceptable control methods need to be designed in collaboration with the communities.
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Affiliation(s)
- S S Imbahale
- Wageningen University and Research Centre, EH Wageningen, The Netherlands.
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Hofhuis A, Reimerink J, Reusken C, Scholte EJ, Boer AD, Takken W, Koopmans M. The hidden passenger of lucky bamboo: do imported Aedes albopictus mosquitoes cause dengue virus transmission in the Netherlands? Vector Borne Zoonotic Dis 2009; 9:217-20. [PMID: 18959501 DOI: 10.1089/vbz.2008.0071] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Since 2005, Aedes albopictus mosquitoes have been detected in companies in the Netherlands that import ornamental plants from China. To assess the risks of dengue transmission, a study was carried out in 48 persons who are professionally exposed to these mosquitoes. No evidence for non-travel-related flavivirus infections was found.
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Affiliation(s)
- A Hofhuis
- National Institute for Public Health and the Environment, Centre for Infectious Disease Control, Bilthoven, The Netherlands.
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Takken W, Balk F, Jansen RC, Koeman JH. The Experimental Application of Insecticides from a Helicopter for the Control of Riverine Populations ofGlossina tachinoidesin West Africa. VI. Observations on Side-Effects. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/09670877809414139] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- W. Takken
- a Department of Toxicology , Agricultural University , Wageningen , Netherlands
- b Joint FAO: IAEA Division of Atomic Energy in Food and Agriculture , Vienna , P.O. Box 590 , Austria
| | - F. Balk
- a Department of Toxicology , Agricultural University , Wageningen , Netherlands
| | - R. C. Jansen
- a Department of Toxicology , Agricultural University , Wageningen , Netherlands
| | - J. H. Koeman
- a Department of Toxicology , Agricultural University , Wageningen , Netherlands
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Molyneux DH, Baldry DAT, van Wettere P, Takken W, de Raadt P. The Experimental Application of Insecticides from a Helicopter for the Control of Riverine Populations of Glossina tachinoides in West Africa. I. Objectives, Experimental Area and Insecticides Evaluated. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/09670877809414134] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- D. H. Molyneux
- a World Health Organization , B.P. 386, Upper Volta, Bobo Dioulasso
- b Department of Biology , University of Salford, Salford M5 4WT , Lancashire , UK
| | - D. A. T. Baldry
- a World Health Organization , B.P. 386, Upper Volta, Bobo Dioulasso
- c Division of Vector Biology and Control , World Health Organization , Geneva , Switzerland
| | - P. van Wettere
- a World Health Organization , B.P. 386, Upper Volta, Bobo Dioulasso
- d c/o American Embassy, USAID , Bamako , Mali
| | - W. Takken
- a World Health Organization , B.P. 386, Upper Volta, Bobo Dioulasso
- e Joint FAO: IAEA Division of Atomic Energy in Food and Agriculture , PO box 590, Vienna , Austria
| | - P. de Raadt
- a World Health Organization , B.P. 386, Upper Volta, Bobo Dioulasso
- f Division of Malaria and other Parasitic Diseases , World Health Organization , Geneva , Switzerland
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Scholte EJ, Dijkstra E, Blok H, De Vries A, Takken W, Hofhuis A, Koopmans M, De Boer A, Reusken CBEM. Accidental importation of the mosquito Aedes albopictus into the Netherlands: a survey of mosquito distribution and the presence of dengue virus. Med Vet Entomol 2008; 22:352-358. [PMID: 19120963 DOI: 10.1111/j.1365-2915.2008.00763.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In the summer of 2005, the Asian tiger mosquito, Aedes albopictus (Skuse) (Diptera: Culicidae) was found for the first time in the Netherlands. It was collected on the premises of several horticultural companies that import the ornamental plant Dracaena sanderiana (Sparagalus: Dracaenaceae [Agavaceae]), known as Lucky bamboo, from southern China, an area endemic for this mosquito species and for arboviruses transmitted by this vector. Here we report the results of a 1-year survey of the distribution and vector status of Ae. albopictus in Lucky bamboo nurseries in the Netherlands (July 2006-June 2007). As it had been established previously that the presence of this species was linked to the import of Lucky bamboo, the survey was conducted only on sites owned by relevant import companies. In total, 569 adult Ae. albopictus were collected with mosquito traps from 15 of the 17 (88%) glasshouses used by Lucky bamboo importers, none of which were found to be infected with dengue virus. On two occasions there was evidence that Ae. albopictus had escaped from the glasshouses, but, overall, there was no evidence that a population had become established in the greenhouses or elsewhere.
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Affiliation(s)
- E-J Scholte
- Dutch Plant Protection Service, Department of Entomology, Wageningen University, Wageningen, The Netherlands.
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Benedict M, D'Abbs P, Dobson S, Gottlieb M, Harrington L, Higgs S, James A, James S, Knols B, Lavery J, O'Neill S, Scott T, Takken W, Toure Y. Guidance for contained field trials of vector mosquitoes engineered to contain a gene drive system: recommendations of a scientific working group. Vector Borne Zoonotic Dis 2008; 8:127-66. [PMID: 18452399 DOI: 10.1089/vbz.2007.0273] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Paaijmans KP, Takken W, Githeko AK, Jacobs AFG. The effect of water turbidity on the near-surface water temperature of larval habitats of the malaria mosquito Anopheles gambiae. Int J Biometeorol 2008; 52:747-53. [PMID: 18633650 DOI: 10.1007/s00484-008-0167-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 04/24/2008] [Accepted: 05/08/2008] [Indexed: 05/19/2023]
Abstract
Water temperature is an important determinant in many aquatic biological processes, including the growth and development of malaria mosquito (Anopheles arabiensis and A. gambiae) immatures. Water turbidity affects water temperature, as suspended particles in a water column absorb and scatter sunlight and hence determine the extinction of solar radiation. To get a better understanding of the relationship between water turbidity and water temperature, a series of semi-natural larval habitats (diameter 0.32 m, water depth 0.16 m) with increasing water turbidity was created. Here we show that at midday (1300 hours) the upper water layer (thickness of 10 mm) of the water pool with the highest turbidity was on average 2.8 degrees C warmer than the same layer of the clearest water pool. Suspended soil particles increase the water temperature and furthermore change the temperature dynamics of small water collections during daytime, exposing malaria mosquito larvae, which live in the top water layer, longer to higher temperatures.
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Affiliation(s)
- K P Paaijmans
- Meteorology and Air Quality, Wageningen University, Wageningen, The Netherlands.
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Meiswinkel R, Baldet T, de Deken R, Takken W, Delécolle JC, Mellor P. The 2006 outbreak of bluetongue in northern Europe—The entomological perspective. Prev Vet Med 2008; 87:55-63. [DOI: 10.1016/j.prevetmed.2008.06.005] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
There is ample evidence that host seeking in mosquitoes is mediated by semiochemicals emanating from the host. Olfactory cues (kairomones) are detected through an intricate pathway, beginning with sensilla located on the antennae (odour) and palpi (CO2). Age and physiological state of the mosquito determine whether detection of kairomones results in a behavioural response. Only a few kairomones have been described so far. CO2 is a kairomone for most mosquito species and signifies the presence of a potential host because of its occurrence in the volatile emissions of all vertebrates. Other chemicals are likely to play a role in mosquito-host interaction as well, notably L-lactic acid, fatty acids and 1-octen-3-ol. Species-specific host preference is thought to be olfactory based and related to the presence of specialized sensilla or perception at the central olfactory pathway. Host specificity is genetically determined, as demonstrated by inherited differences within members of the Anopheles gambiae complex. In view of the available evidence, challenging research areas are: (1) the function of olfactory receptors and the level of specialization; (2) the identification of general and host-specific kairomones; (3) demonstration of behavioural responses to laboratory-identified olfactory cues in the field; (4) studying whether mosquito host-locating behaviour can be manipulated by kairomones; (5) the genetics of the regulation of olfactory behaviour; and (6) determining whether there is an olfactory basis for the evolution of mosquito-host interactions.
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Affiliation(s)
- W Takken
- Department of Entomology, Wageningen Agricultural University, The Netherlands
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Qiu YT, Smallegange RC, Van Loon JJA, Ter Braak CJF, Takken W. Interindividual variation in the attractiveness of human odours to the malaria mosquito Anopheles gambiae s. s. Med Vet Entomol 2006; 20:280-7. [PMID: 17044878 DOI: 10.1111/j.1365-2915.2006.00627.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Differences between human individuals in their attractiveness to female mosquitoes have been reported repeatedly, but the underlying mechanisms are not well understood. Skin emanations from 27 human individuals, collected on glass marbles, were tested against ammonia in a dual-choice olfactometer to establish their degrees of attractiveness to anthropophilic Anopheles gambiae s.s. Giles (Diptera: Culicidae) mosquitoes. Ammonia was used as a standard odour source because of its proven attractiveness to An. gambiae s.s. Skin emanations from most volunteers attracted significantly more mosquitoes than ammonia. There were clear differences in the attractiveness of skin emanations from different volunteers relative to that of ammonia, as well as in the strength of the trap entry response. Consistent differences were observed when emanations from the three most and the three least attractive volunteers were tested pairwise. No gender or age effect was found for relative attractiveness or trap entry response. Emanations from volunteers with higher behavioural attractiveness elicited higher electroantennogram response amplitudes in two pairs, but in a third pair a higher electroantennogram response was found for the less attractive volunteer. These results confirm that odour contributes to the differences in attractiveness of humans to mosquitoes.
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Affiliation(s)
- Y T Qiu
- Laboratory of Entomology, Wageningen University, Wageningen, the Netherlands
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Koenraadt CJM, Paaijmans KP, Schneider P, Githeko AK, Takken W. Low larval vector survival explains unstable malaria in the western Kenya highlands. Trop Med Int Health 2006; 11:1195-205. [PMID: 16903883 DOI: 10.1111/j.1365-3156.2006.01675.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Several highland areas in eastern Africa have recently suffered from serious malaria epidemics. Some models predict that, in the short term, these areas will experience more epidemics as a result of global warming. However, the various processes underlying these changes are poorly understood. We therefore investigated malaria prevalence, malaria vector densities and malaria vector survival in a highland area in western Kenya, ranging from approximately 1,550-1,650 m altitude. Although only five adult malaria vectors were collected during 180 light traps and 180 resting collections over a 23-month study period, malaria was prevalent among school children (average parasite prevalence: 10%). During an extensive survey of potential larval habitats, we identified only seven habitats containing Anopheles gambiae Giles s.l. larvae. Their limited number and low larval densities suggested that their contribution to the adult vector population was small. Experiments on adult and larval survival showed that at this altitude, adult mosquitoes survived inside local houses, but that larval development was severely retarded: only 2 of 500 A. gambiae s.l. larvae developed to the pupal stage, whereas all other larvae died prior to pupation. At present, high vector densities are unlikely because of unfavourable abiotic conditions in the area. However, temporary favourable conditions, such as during El Niño years, may increase larval vector survival and may lead to malaria epidemics.
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Affiliation(s)
- C J M Koenraadt
- Laboratory of Entomology, Department of Plant Sciences, Wageningen University, The Netherlands.
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Pates HV, Takken W, Curtis CF, Jamet H. Zoophilic Anopheles quadriannulatus species B found in a human habitation in Ethiopia. Ann Trop Med Parasitol 2006; 100:177-9. [PMID: 16492366 DOI: 10.1179/136485906x86374] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- H V Pates
- Amani Medical Research Centre, P.O. Box 81, Muheza, Tanzania.
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Qiu YT, Smallegange RC, Hoppe S, van Loon JJA, Bakker EJ, Takken W. Behavioural and electrophysiological responses of the malaria mosquito Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) to human skin emanations. Med Vet Entomol 2004; 18:429-38. [PMID: 15642010 DOI: 10.1111/j.0269-283x.2004.00534.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Behavioural and electrophysiological responses of Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) to human skin emanations collected on glass beads were studied using a dual-port olfactometer and electroantannography. Glass beads to which skin emanations from human hands had been transferred elicited a level of attraction similar to a human hand. The attractiveness of these handled glass beads faded away 4 h after transfer onto the beads. Storage at -20 degrees C for up to 8 weeks showed a decreased but still attractive effect of the beads. In a choice test between one individual and four others, the emanations from the reference individual were significantly more attractive in three out of four cases. The headspace of handled glass beads elicited a dose-dependent EAG response. The substances causing EAG activity could be removed partially by dichloromethane, ethanol and pentane-ether. Glass beads provide a suitable neutral substrate for the transfer of human odour to enable chemical analysis of the human skin emanations for identification of kairomones of anthropophilic mosquitoes.
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Affiliation(s)
- Y T Qiu
- Laboratory of Entomology, Wageningen University, Wageningen, the Netherlands
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Abstract
Mosquitoes that act as disease vectors rely upon olfactory cues to direct several important behaviors that are fundamentally involved in establishing their overall vectorial capacity. Of these, the propensity to select humans for blood feeding is arguably the most important of these olfactory driven behaviors in so far as it significantly contributes to the ability of these mosquitoes to transmit pathogens that cause diseases such as dengue, yellow fever and most significantly human malaria. Here, we review significant advances in behavioral, physiological and molecular investigations into mosquito host preference, with a particular emphasis on studies that have emerged in the post-genomic era that seek to combine these approaches.
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Affiliation(s)
- L J Zwiebel
- Department of Biological Sciences, Program in Developmental Biology and Center for Molecular Neuroscience, Vanderbilt University, VU Station, B 3582, Nashville, TN 37235-3582, USA.
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Koenraadt C, Githeko A, Takken W. Erratum to “The effects of rainfall and evapotranspiration on the temporal dynamics of Anopheles gambiae s.s. and Anopheles arabiensis in a Kenyan village”. Acta Trop 2004. [DOI: 10.1016/j.actatropica.2004.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Foster WA, Takken W. Nectar-related vs. human-related volatiles: behavioural response and choice by female and male Anopheles gambiae (Diptera: Culicidae) between emergence and first feeding. Bull Entomol Res 2004; 94:145-157. [PMID: 15153297 DOI: 10.1079/ber2003288] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The close association of Anopheles gambiae Giles with humans and its females' ability to live on human blood alone suggest that females may ignore sources of sugar in favour of human blood as a source of energy. They have limited energy reserves at emergence, and at 27 degrees C both sexes generally die if they do not feed during night 1, 24-36 h after emergence. Food preferences during this critical period were tested by measuring responses to volatiles from honey and soiled socks, which served as surrogates for nectar-related and human-related volatiles in a wind-tunnel olfactometer. Both sexes responded more strongly to honey than to human volatiles, and given a choice, preferred honey over human volatiles. After 5 days of sugar access and maturation, males continued to prefer honey volatiles, whereas females changed behaviour, responding almost exclusively to human volatiles. Night 1 experiments also demonstrated that: (i). females previously having had sugar during the night of emergence responded more strongly to human volatiles; (ii). large-bodied mosquitoes of both sexes responded more strongly to honey than small-bodied ones; and (iii). females were equally responsive to honey in both early and late scotophase but were slightly more responsive to human volatiles in late scotophase. These results indicate that for a female's first meal, sugar is a viable option and is preferred when nectar-related stimuli are strong. This supports field evidence that sugar-feeding is a significant component of A. gambiae female behaviour.
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Affiliation(s)
- W A Foster
- Department of Entomology, The Ohio State University, Columbus, OH 43210-1220, USA.
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Koenraadt CJM, Githeko AK, Takken W. The effects of rainfall and evapotranspiration on the temporal dynamics of Anopheles gambiae s.s. and Anopheles arabiensis in a Kenyan village. Acta Trop 2004; 90:141-53. [PMID: 15177140 DOI: 10.1016/j.actatropica.2003.11.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2003] [Revised: 10/24/2003] [Accepted: 11/04/2003] [Indexed: 11/18/2022]
Abstract
The population dynamics of the larval and adult life stages of the malaria vector Anopheles gambiae Giles were studied in Miwani, western Kenya, in relation to meteorological conditions. Larval density within a habitat, the number of larval habitats and sibling species composition were investigated as determinants of larval population dynamics. Female vector densities inside local houses and sibling species composition were investigated as determinants of adult population dynamics. Larval densities were estimated using a modified area-sampling method. Within the habitats, all instars showed a highly aggregated distribution, with the exception of second instars. A longitudinal study on the larval populations of A. gambiae s.l. in two different types of habitat (dirt track and ditch) was carried out, using a novel sampling procedure. A. gambiae s.s. and Anopheles arabiensis, the two sibling species occurring sympatrically in the study area, showed some spatial segregation between the two types of habitat. Rainfall was significantly correlated with the number of A. gambiae s.l. larval habitats during the first 6 weeks of study taking 1 week time lag into account, while over the entire 5-month study period correlations were less clear. With 1 week time lag, rainfall was also significantly correlated with the number of female A. gambiae s.l. collected from CDC-light traps in the study houses. Both larval and adult populations showed a significant increase in the proportion of A. gambiae s.s. within the mixed population of A. gambiae s.s. and A. arabiensis over time. Although not significantly correlated, the ratio of rainfall over precipitation/potential evapotranspiration (P/PE), indicative of the humidity conditions in the area, was probably the driving force of this increase.
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Affiliation(s)
- C J M Koenraadt
- Laboratory of Entomology, Department of Plant Sciences, Wageningen University, P.O. Box 8031, 6700 EH Wageningen, The Netherlands
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Abstract
Among the aquatic developmental stages of the Anopheles gambiae complex (Diptera: Culicidae), both inter- and intra-specific interactions influence the resulting densities of adult mosquito populations. For three members of the complex, An. arabiensis Patton, An. quadriannulatus (Theobald) and An. gambiae Giles sensu stricto, we investigated some aspects of this competition under laboratory conditions. First-instar larvae were consumed by fourth-instar larvae of the same species (cannibalism) and by fourth-instar larvae of other sibling species (predation). Even when larvae were not consumed, the presence of one fourth-instar larva caused a significant reduction in development rate of first-instar larvae. Possible implications of these effects for population dynamics of these malaria vector mosquitoes are discussed.
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Affiliation(s)
- C J M Koenraadt
- Laboratory of Entomology, Department of Plant Sciences, Wageningen University, the Netherlands
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Abstract
A field study was carried out in the large-scale rice irrigation scheme of the Office du Niger in Mali to investigate the relation between anopheline mosquito larval development and small-scale differences in irrigation practices, such as water level, irrigation application and irrigation frequency. The objective of the study was to find out if water management can be used as a tool for vector control to reduce the malaria transmission risk. Larvae of Anopheles gambiae s.s.,; the main malaria vector in the study area, developed mostly in the first 6 weeks after transplanting the rice. During rice development, a succession of anopheline species was observed. This was associated with a marked decrease in light intensity reaching the water surface as plant height increased. Minor differences in water management resulted in noticeable variations in larval densities and species composition. A. gambiae s.s. larvae were most abundant during the early growing stages and almost absent in a closed rice crop. Due to improper drainage after harvest, A. gambiae s.s. breeding was soon re-established in fields where small pools of water were retained. The results suggest that larval mosquito habitats in the Office du Niger can be significantly reduced by water management, simultaneous planting and harvesting and proper drainage of fallow fields.
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Affiliation(s)
- E Klinkenberg
- Irrigation and Water Engineering Group, Wageningen University and Research Centre, Nieuwe Kanaal 11, 6709 PA, Wageningen, The Netherlands
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Mukabana WR, Takken W, Seda P, Killeen GF, Hawley WA, Knols BGJ. Extent of digestion affects the success of amplifying human DNA from blood meals of Anopheles gambiae (Diptera: Culicidae). Bull Entomol Res 2002; 92:233-239. [PMID: 12088540 DOI: 10.1079/ber2002164] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The success of distinguishing blood meal sources of Anopheles gambiae Giles through deoxyribonucleic acid (DNA) profiling was investigated by polymerase chain reaction (PCR) amplification at the TC-11 and VWA human short tandem repeats (STR) loci. Blood meal size and locus had no significant effect on the success of amplifying human DNA from blood meals digested for 0, 8, 16, 24 and 32 h (P = 0.85 and 0.26 respectively). However, logistic regression found a significant negative relationship between time since ingestion and the success probability of obtaining positive PCR products among meals digested for between 8 and 32 h (P = 0.001). Approximately 80% of fresh blood meals were successfully profiled. After 8 h, the proportion of blood meals that could be successfully profiled decreased slowly with time after ingestion, dropping to below 50% after approximately 15 h. There was no significant difference in the success of amplifying human DNA from blood meals of mosquitoes killed at time 0 and 8 h after ingestion (P = 0.272).
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Affiliation(s)
- W R Mukabana
- International Centre of Insect Physiology and Ecology (ICIPE), PO Box 30772, Nairobi, Kenya.
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Dekker T, Takken W, Braks MA. Innate preference for host-odor blends modulates degree of anthropophagy of Anopheles gambiae sensu lato (Diptera: Culicidae). J Med Entomol 2001; 38:868-71. [PMID: 11761386 DOI: 10.1603/0022-2585-38.6.868] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In field studies, Anopheles gambiae Giles sensu stricto obtains most blood meals from humans, whereas Anopheles quadriannulatus Theobald bites predominantly bovids. We investigated whether host odors modulate the host preference of these mosquito species. In a dual-choice olfactometer, mosquitoes were given a choice between clean air and putative host-specific odor blends. An. gambiae chose 'human odor' over clean air and clean air over cow odor.' Although Anopheles quadriannulatus did not choose cow odor over clean air, it chose clean air over human odor. Cheese odor, which attracted An. gambiae, did not result in higher trap catch of An. quadriannulatus. We conclude that the degree of anthropophagy of An. gambiae s.l. has an innate olfactory basis.
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Affiliation(s)
- T Dekker
- Laboratory of Entomology, Wageningen University, The Netherlands.
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36
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Abstract
The strongly anthropophilic behaviour of Anopheles gambiae Giles sensu stricto (Diptera: Culicidae), the most important malaria vector in Africa, has been demonstrated by field and laboratory studies. Other members of the An. gambiae complex express varied degrees of anthropophily. Anopheles quadriannulatus (Theobald) species A and B are more zoophilic members of the complex and hence are considered to be of no medical importance. Olfactometer experiments with An. quadriannulatus species A have demonstrated attraction to both human and cow odour. To extend these olfactometer observations a choice experiment was conducted in an outdoor cage with a human and a calf as baits, using laboratory-reared mosquitoes. Anopheles gambiae s.s. (from Liberia) and two strains of An. quadriannulatus species A (SKUQUA from South Africa, SANGQUA from Zimbabwe), marked with different coloured fluorescent powders for identification purposes, were released simultaneously and given an equal opportunity to feed on either host. The experiment was repeated six times. Bloodmeals were identified using the precipitin technique. Anopheles gambiae s.s. showed highly anthropophagic behaviour, taking 88% of bloodmeals from the human host. In contrast, both strains of An. quadriannulatus fed with equal frequency on the human or the calf; the response to either host was not significantly different. These results confirm the olfactometer findings and demonstrate anthropophagic behaviour not previously recorded in this species. This finding has implications for prospective manipulation of host preference for genetic control purposes.
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Affiliation(s)
- H V Pates
- Laboratory of Entomology, Wageningen Agricultural University, The Netherlands
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Pates HV, Takken W, Stuke K, Curtis CF. Differential behaviour of Anopheles gambiae sensu stricto (Diptera: Culicidae) to human and cow odours in the laboratory. Bull Entomol Res 2001; 91:289-296. [PMID: 11587625 DOI: 10.1079/ber200198] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A dual port olfactometer was used to study the response of Anopheles gambiae Giles sensu stricto to odours of human and animal origin. Human odour consisted of human skin emanations collected on a nylon stocking, which was worn for 24 h. This was tested alone or together with 4.5% carbon dioxide, the concentration in human and cattle breath. Cattle odours consisted of cow skin emanations and/or carbon dioxide. Cow skin emanations were collected by tying a nylon stocking ('cow sock') around the hind leg of a cow for 12 h. Anopheles gambiae s.s. was consistently highly attracted by human odour, which is consistent with the high degree of anthropophily in this mosquito. Anopheles gambiae s.s. was not attracted by human or cattle equivalent volumes of carbon dioxide and this gas did not enhance the effect of human skin residues. Furthermore, A. gambiae s.s. showed a high degree of aversion to cow odour. When human odour and cow odour were tested together in the same port, mosquitoes were still highly attracted, indicating that whilst cattle odour may deter A. gambiae s.s., these mosquitoes can detect human odour in the presence of cattle odour. It was concluded that carbon dioxide plays a minor role in the host seeking behaviour of A. gambiae s.s., whilst host specific cues such as human skin residues play a major role and very effectively demonstrated anthropophilic behaviour in the laboratory.
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Affiliation(s)
- H V Pates
- Laboratory of Entomology, Wageningen Agricultural University, PO Box 8031, Wageningen, 6700 EH, The Netherlands
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38
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Takken W, Adam W. Inhibition of host-seeking response and olfactory responsiveness in Anopheles gambiae following blood feeding. J Insect Physiol 2001; 47:303-310. [PMID: 11119776 DOI: 10.1016/s0022-1910(00)00107-4] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The effect of a single blood meal on the host-seeking response of Anopheles gambiae was investigated in the laboratory using a behavioural bioassay, whereas possible changes at the chemosensory level were monitored using electroantennogram recording (EAG). To avoid the possible confounding effect of body size, mosquitoes of a large size class only were used. Five-day old female mosquitoes were given a blood meal on a human arm and exposed to the emanations of a human hand in an olfactometer at 3, 24, 40, 48 and 72 h following the meal and their behaviour and EAG response to host stimuli were compared with that of unfed mosquitoes (controls) of corresponding age. During egg development, mosquitoes had access to glucose and an oviposition tray. The ovarian development of blood-fed mosquitoes that responded to host odours was compared with that of blood-fed mosquitoes that had not been exposed to host odours. The EAG response of blood-fed and control mosquitoes to host odour was examined upon stimulation with air led over incubated human sweat, hexanoic acid, indole and geranyl acetone. EAGs were recorded at times after a blood meal corresponding with those used in the behavioural experiment. There was no host-seeking response at 3 and 24 h post blood meal (pbm). Seven percent of the mosquitoes responded to human emanations 40-h pbm, 27% at 48 h and 68% at 72 h following a blood meal. The average response of controls to host stimuli varied from 35 (at t=40 h) to 67%. There was no ovarian development in the unfed group of mosquitoes. Of the mosquitoes that responded to host odour 48 h pbm, 12.5% (n=5) had ovaries in Christophers' stage IV and the remainder in stage V. Of the mosquitoes that responded 72 h pbm, 66.7% (n=94) had ovaries in stage V and 31.2% (n=44) had recently oviposited. Maximum EAG amplitudes recorded from blood-fed and control mosquitoes were similar for mosquitoes in Christophers' stages I-III, whereas in stage IV EAG amplitudes recorded from the blood-fed group were significantly lower than those of the corresponding control group in response to headspace of incubated human sweat and to indole. The results show that there was a strong inhibition of host seeking in An. gambiae for a period of at least 40 h following a blood meal. Host-seeking returned to pre-blood meal levels 72-h post feeding and was associated with egg maturation. The inhibition of host-seeking behaviour was accompanied by an inhibition of olfactory sensitivity to headspace of incubated sweat and indole just before the resumption of the host-seeking response. The implications of these findings for mosquito surveillance with host odours are discussed.
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Affiliation(s)
- W Takken
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH, Wageningen, The Netherlands
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39
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Abstract
For collecting mosquitoes (Diptera: Culicidae) the outdoor catching efficiency of four types of trapping devices baited with carbon dioxide (CO2, 300 ml/ min) was evaluated and compared in two areas of Tanzania. The types of traps employed were: the CDC miniature trap with the incandescent light bulb switched on or off; electric nets (ENT) and a Counterflow Geometry (CFG) trap. In Njage, southeast Tanzania, Anopheles gambiae Giles sensu stricto was the most abundant of the seven mosquito species obtained, comprising of 74.3% of the total number caught (n=2,171). In Muheza, north-east Tanzania, Culex quinquefasciatus Say was the predominant species (90.9%) among 1,080 caught. At both localities the CFG trap was superior to the CDC trap with light-on or light-off for sampling both An. gambiae and Cx. quinquefasciatus. Efficiency of the CFG trap and ENT were similar for sampling these species of mosquitoes (P > 0.05). However, ENT was superior to the CDC trap with light-off for collecting both species. Significantly more (P < 0.05) Cx. quinquefasciatus were obtained by the CDC trap with light-off than with light-on, especially outdoors. It is concluded that both ENT and the CFG are effective tools for sampling populations of An. gambiae and Cx. quinquefasciatus outdoors.
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Abstract
Mosquito larvae of the sibling species Anopheles arabiensis Patton and An. gambiae Giles sensu stricto (Diptera: Culicidae) were investigated for interspecific competition. Single-species and mixed-species populations were reared at 27 degrees C from the first instar to pupation at different densities (100, 200 or 400 larvae/200 cm2 tray) with a constant amount of food, 0.2 mg/larva/day. Pupae obtained from mixed populations were identified to species using PCR. Both species had a 1:1 sex ratio at pupation. Development time to pupation averaged about one day less for An. arabiensis compared to An. gambiae, ranging from 0.93-1.49d for males and from 0.44-0.84 d for females in single populations. In mixed species populations the difference for males ranged from 0.99-1.58d and for females from 0.93-1.62d. Survival rates of An. gambiae s.s. were significantly higher than those of An. arabiensis in both the single-species and mixed-species populations. Mixed-species rearing did not have an effect on the survival of An. gambiae, whereas the mortality rate of An. arabiensis was significantly higher in mixed populations than when only this species was reared at the same densities, suggesting a competitive disadvantage for An. arabiensis in mixed populations. High proportions of larvae (4-35%) were lost during development; these losses could not be accounted for by corpses found in the rearing pans. The possibility of cannibalism was investigated by rearing each species separately in small containers (five per 50 ml), inspected every 6h, but no cannibalism was detected at any stage of development in either species. It was concluded that, under these experimental circumstances, interspecific competition between both species did occur but with a detrimental effect on An. arabiensis only. Relevance of these findings to the ecology of both species in the field is discussed briefly.
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Affiliation(s)
- P Schneider
- Laboratory of Entomology, Wageningen Agricultural University, The Netherlands
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Mboera LE, Takken W, Sambu EZ. The response of Culex quinquefasciatus (Diptera: culicidae) to traps baited with carbon dioxide, 1-octen-3-ol, acetone, butyric acid and human foot odour in Tanzania. Bull Entomol Res 2000; 90:155-159. [PMID: 10948375 DOI: 10.1017/s0007485300000262] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The responses of Culex quinquefasciatus Say to traps baited with carbon dioxide, 1-octen-3-ol, acetone, butyric acid and human foot odour were studied in the field in Muheza, north-east Tanzania using Counterflow Geometry (CFG) and Centers for Disease Control (CDC) traps. It was found that significantly more C. quinquefasciatus responded to foot odour collected on nylon stockings than to clean nylon stockings (P < 0.05). Significantly more mosquitoes were caught in a CFG trap baited with carbon dioxide than in traps with either human foot odour, acetone or butyric acid. It was also found that in an outdoor situation a carbon dioxide baited CDC unlit trap collected over 12 times more C. quinquefasciatus than an unbaited CDC unlit trap and nine times more mosquitoes than CDC traps baited with 1-octen-3-ol alone (P < 0.05). The number of mosquitoes caught in a CDC trap baited with 1-octen-3-ol did not differ significantly from that of the unbaited CDC trap (P > 0.05). These results indicate that the Afrotropical C. quinquefasciatus respond significantly better to traps baited with carbon dioxide than to either octenol, acetone or butyric acid, and that human foot odour contains stimuli to which C. quinquefasciatus is attracted under field conditions.
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Affiliation(s)
- L E Mboera
- National Institute for Medical Research, Ubwari Field Station, PO Box 81, Muheza, Tanzania
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42
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Affiliation(s)
- W Takken
- Laboratory of Entomology, Wageningen Agricultural University, The Netherlands
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43
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Mboera LE, Takken W, Mdira KY, Pickett JA. Sampling gravid Culex quinquefasciatus (Diptera: Culicidae) in Tanzania with traps baited with synthetic oviposition pheromone and grass infusions. J Med Entomol 2000; 37:172-176. [PMID: 15218923 DOI: 10.1603/0022-2585-37.1.172] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The effectiveness of traps baited with (5R,6S)-6-acetoxy-5-hexadecanolide (the synthetic oviposition pheromone) and grass infusions in sampling a population of gravid Culex quinquefasciatus Say was conducted in Muheza, Northeast Tanzania. A counterflow geometry (CFG) trap baited with pheromone and set outdoors, adjacent to a pit latrine building, collected more gravid Cx. quinquefasciatus than a CDC trap baited with pheromone and operated without light. Inside pit latrine buildings, significantly more gravid Cx. quinquefasciatus were collected in a CFG trap-baited with pheromone or grass infusion than in traps baited with tap water. CFG traps baited with either grass infusion or pheromone and set outdoors, away from known breeding sites, caught significantly more gravid Cx. quinquefasciatus than traps baited with tap water. CFG traps baited with pheromone + grass infusion caught significantly more gravid Cx. quinquefasciatus than CFG traps baited with either grass infusion or pheromone. In both cases, the proportion of gravid mosquitoes increased as traps were moved away from a natural emergence site. More gravid Cx. quinquefasciatus were collected in a pheromone-baited CFG trap than were egg rafts deposited in a jar with pheromone-treated water. It is concluded that CFG traps baited with oviposition attractants can be used effectively to sample gravid Cx. quinquefasciatus.
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Affiliation(s)
- L E Mboera
- National Institute for Medical Research, Ubwari Field Station, Muheza, Tanzania
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45
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Takken W, Eling W, Hooghof J, Dekker T, Hunt R, Coetzee M. Susceptibility of Anopheles quadriannulatus Theobald (Diptera: Culicidae) to Plasmodium falciparum. Trans R Soc Trop Med Hyg 1999; 93:578-80. [PMID: 10717736 DOI: 10.1016/s0035-9203(99)90054-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Anopheles quadriannulatus, the cattle-feeding member of the An. gambiae complex, was fed human blood which contained cultured gametocytes of Plasmodium falciparum, using a membrane feeding system. After 7 days, 33-80% of the mosquitoes that took a blood meal contained developing oocysts. In 7 out of 12 females sporozoites were found in the salivary glands 14 days after the infectious blood meal. Control groups of An. gambiae s.s. and An. stephensi became readily infected with > 90% developing oocysts. All of the An. gambiae dissected 14 days after the infectious blood meal had sporozoites in their salivary glands. The results demonstrate that An. quadriannulatus is susceptible to infections with P. falciparum.
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Affiliation(s)
- W Takken
- Laboratory of Entomology, Wageningen Agricultural University, The Netherlands.
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46
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Curtis CF, Pates HV, Takken W, Maxwell CA, Myamba J, Priestman A, Akinpelu O, Yayo AM, Hu JT. Biological problems with the replacement of a vector population by Plasmodium-refractory mosquitoes. Parassitologia 1999; 41:479-81. [PMID: 10697905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Attempts are being made to backcross into Anopheles gambiae s.s. the gene(s) which cause zoophily in Anopheles quadriannulatus. Such a backcrossed strain might be preferable to a Plasmodium-refractory strain as a basis for genetic control because a refractory strain could select for evasion of refractoriness in the wild Plasmodium population. The species composition of the malaria vector population in several Tanzanian villages was overwhelmingly An. gambiae s.s. in a normal rainy season, but consisted of four species, all proved by ELISA and/or PCR to carry P. falciparum sporozoites, at the time of the heavy rains associated with El Niño. Thus any scheme, for malaria transmission control by replacement of vectors by genetically-manipulated non-vectors, would have to be able to replace more than one species.
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Affiliation(s)
- C F Curtis
- London School of Hygiene and Tropical Medicine, UK.
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47
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Takken W, Kager PA, van der Kaay HJ. [A return of endemic malaria to the Netherlands is highly unlikely]. Ned Tijdschr Geneeskd 1999; 143:836-8. [PMID: 10347651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
The Netherlands has been free from malaria since the early 1960, due to a combination of factors: active search and treatment of patients and parasite carriers, targeted use of insecticides, changes in farming and in housing of man and cattle, pollution of surface water with phosphates and the fact that surface waters became fresher. These factors reduced the mosquito population that is dependent on brackish water. The Dutch malaria mosquito cannot transmit the parasite of tropical malaria. The mosquito population could possibly increase due to measures to 'develop nature' but the number of parasite carriers, the acute disease manifestations, the quality and organization of the health care system make it extremely unlikely that local transmission will occur. Fears that malaria may become endemic and that the population in the western parts of the country will have to apply malaria chemoprophylaxis in the near future, are unfounded.
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Affiliation(s)
- W Takken
- Landbouwuniversiteit, Laboratorium voor Entomologie, Wageningen
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48
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49
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Abstract
The African mosquito species Anopheles gambiae sensu lato s.l. and Anopheles funestus rank among the world's most efficient vectors of human malaria. Their unique bionomics, particularly their anthropophilic, endophagic and endophilic characters, guarantee a strong mosquito-host interaction, favorable to malaria transmission. Olfactory cues govern the various behaviors of female mosquitoes and here we review the role of semiochemicals in the life history of African malaria vectors. Recent evidence points towards the existence of human-specific kairomones affecting host-seeking A. gambiae s.l., and efforts are under way to identify the volatiles mediating this behavior. Based on examples from other Culicidae spp., it is argued that there is good reason to assume that mating, sugar feeding, and oviposition behavior in Afrotropical malaria vectors may also be mediated by semiochemicals. It is foreseen that increased knowledge of odor-mediated behaviors will be applied in the development of novel sampling techniques and possibly alternative methods of intervention to control malaria.
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Affiliation(s)
- W Takken
- Laboratory of Entomology, Wageningen Agricultural University, The Netherlands.
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50
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Mboera LE, Knols BG, Takken W, Huisman PW. Olfactory responses of female Culex quinquefasciatus Say (Diptera: Culicidae) in a dual-choice olfactometer. J Vector Ecol 1998; 23:107-113. [PMID: 9879067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Olfactory responses of individual female (n = 1010) Culex quinquefasciatus Say (Diptera: Culicidae) to various odor stimuli were studied in a dual-choice olfactometer. Responses (i.e., the number of mosquitoes entering either of both olfactometer ports) were studied towards clean conditioned air (control), human foot skin emanations (collected on worn stockings), carbon dioxide (4.5% in clean air), moistened air, and various combinations thereof. Skin emanations were significantly more attractive (chi 2 = 23.0, p < 0.001) than clean stockings (control). The mosquito was also significantly more attracted (chi 2 = 7.7, p < 0.01) to skin emanations than to a clean stocking to which water (an equivalent of that absorbed by a worn stocking) was added. A moistened (1 g H2O) clean stocking, however, was slightly more attractive than a dry stocking (chi 2 = 6, p < 0.025). Carbon dioxide (4.5%) did not elicit higher responses than clean air, and no synergistic effect was observed in combination with skin emanations. With the aim of developing an odor-baited trap, our results indicate that Cx. quinquefasciatus responds well to human body odors which can be collected on polyamide materials.
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Affiliation(s)
- L E Mboera
- Laboratory of Entomology, Wageningen Agricultural University, The Netherlands
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