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Buxton M, Nyamukondiwa C, Dalu T, Cuthbert RN, Wasserman RJ. Implications of increasing temperature stress for predatory biocontrol of vector mosquitoes. Parasit Vectors 2020; 13:604. [PMID: 33261665 PMCID: PMC7706185 DOI: 10.1186/s13071-020-04479-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/05/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Predators play a critical role in regulating larval mosquito prey populations in aquatic habitats. Understanding predator-prey responses to climate change-induced environmental perturbations may foster optimal efficacy in vector reduction. However, organisms may differentially respond to heterogeneous thermal environments, potentially destabilizing predator-prey trophic systems. METHODS Here, we explored the critical thermal limits of activity (CTLs; critical thermal-maxima [CTmax] and minima [CTmin]) of key predator-prey species. We concurrently examined CTL asynchrony of two notonectid predators (Anisops sardea and Enithares chinai) and one copepod predator (Lovenula falcifera) as well as larvae of three vector mosquito species, Aedes aegypti, Anopheles quadriannulatus and Culex pipiens, across instar stages (early, 1st; intermediate, 2nd/3rd; late, 4th). RESULTS Overall, predators and prey differed significantly in CTmax and CTmin. Predators generally had lower CTLs than mosquito prey, dependent on prey instar stage and species, with first instars having the lowest CTmax (lowest warm tolerance), but also the lowest CTmin (highest cold tolerance). For predators, L. falcifera exhibited the narrowest CTLs overall, with E. chinai having the widest and A. sardea intermediate CTLs, respectively. Among prey species, the global invader Ae. aegypti consistently exhibited the highest CTmax, whilst differences among CTmin were inconsistent among prey species according to instar stage. CONCLUSION These results point to significant predator-prey mismatches under environmental change, potentially adversely affecting natural mosquito biocontrol given projected shifts in temperature fluctuations in the study region. The overall narrower thermal breadth of native predators relative to larval mosquito prey may reduce natural biotic resistance to pests and harmful mosquito species, with implications for population success and potentially vector capacity under global change.
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Affiliation(s)
- Mmabaledi Buxton
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Palapye, Botswana
| | - Casper Nyamukondiwa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Palapye, Botswana.
| | - Tatenda Dalu
- Department of Ecology and Resource Management, University of Venda, Thohoyandou, 0950, South Africa
| | - Ross N Cuthbert
- GEOMAR, Helmholtz-Zentrum für Ozeanforschung Kiel, 24105, Kiel, Germany
| | - Ryan J Wasserman
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Palapye, Botswana
- Department of Zoology and Entomology, Rhodes University, Makhanda, 6140, South Africa
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2
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Awono-Ambene PH, Etang J, Antonio-Nkondjio C, Ndo C, Eyisap WE, Piameu MC, Mandeng ES, Mbakop RL, Toto JC, Patchoke S, Mnzava AP, Knox TB, Donnelly M, Fondjo E, D. Bigoga J. The bionomics of the malaria vector Anopheles rufipes Gough, 1910 and its susceptibility to deltamethrin insecticide in North Cameroon. Parasit Vectors 2018; 11:253. [PMID: 29669580 PMCID: PMC5907476 DOI: 10.1186/s13071-018-2809-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 03/25/2018] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Following the recent discovery of the role of Anopheles rufipes Gough, 1910 in human malaria transmission in the northern savannah of Cameroon, we report here additional information on its feeding and resting habits and its susceptibility to the pyrethroid insecticide deltamethrin. METHODS From 2011 to 2015, mosquito samples were collected in 38 locations across Garoua, Mayo Oulo and Pitoa health districts in North Cameroon. Adult anophelines collected using outdoor clay pots, window exit traps and indoor spray catches were checked for feeding status, blood meal origin and Plasmodium circumsporozoite protein. The susceptibility of field-collected An. rufipes to deltamethrin was assessed using WHO standard procedures. RESULTS Of 9327 adult Anopheles collected in the 38 study sites, An. rufipes (6.5%) was overall the fifth most abundant malaria vector species following An. arabiensis (52.4%), An. funestus (s.l.) (20.8%), An. coluzzii (12.6%) and An. gambiae (6.8%). This species was found outdoors (51.2%) or entering houses (48.8%) in 35 suburban and rural locations, together with main vector species. Apart from human blood with index of 37%, An. rufipes also fed on animals including cows (52%), sheep (49%), pigs (16%), chickens (2%) and horses (1%). The overall parasite infection rate of this species was 0.4% based on the detection of P. falciparum circumsporozoite proteins in two of 517 specimens tested. Among the 21 An. rufipes populations assessed for deltamethrin susceptibility, seven populations were classified as "susceptible" (mortality ≥ 98%) , ten as "probable resistant" with a mortality range of 90-97% and four as "resistant" with a mortality range of 80-89%. CONCLUSIONS This study revealed changeable resting and feeding behaviour of An. rufipes, as well as further evidence on its ability to carry human malaria parasites in North Cameroon. Besides, this species is developing physiological resistance to deltamethrin insecticide which is used in treated nets and agriculture throughout the country, and should be regarded as one of potential targets for the control of residual malaria parasite transmission in Africa.
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Affiliation(s)
- Parfait H. Awono-Ambene
- Research Institute of Yaounde (IRY), Organization de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroon
| | - Josiane Etang
- Research Institute of Yaounde (IRY), Organization de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, P.O. Box 2701, Douala, Cameroon
| | - Christophe Antonio-Nkondjio
- Research Institute of Yaounde (IRY), Organization de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroon
| | - Cyrille Ndo
- Research Institute of Yaounde (IRY), Organization de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, P.O. Box 2701, Douala, Cameroon
| | | | - Michael C. Piameu
- Ecole des Sciences de la Santé, Université Catholique d’Afrique Centrale, B.P. 1110, Yaoundé, Cameroon
| | - Elysée S. Mandeng
- Faculty of Sciences, University of Yaoundé I, P.O. Box 812, Yaounde, Cameroon
| | - Ranaise L. Mbakop
- Faculty of Sciences, University of Yaoundé I, P.O. Box 812, Yaounde, Cameroon
| | - Jean Claude Toto
- Research Institute of Yaounde (IRY), Organization de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroon
| | - Salomon Patchoke
- National Malaria Control Programme, Ministry of Public Health, P.O. Box 14386, Yaoundé, Cameroon
| | - Abraham P. Mnzava
- The African Leaders Malaria Alliance (ALMA), 3 Barack Obama Drive, P.O. Box 70198, 11101 Dar es Salaam, Tanzania
| | - Tessa B. Knox
- Global Malaria Programme, World Health Organization, Avenue Appia, Geneva, Switzerland
| | - Martin Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA UK
| | - Etienne Fondjo
- National Malaria Control Programme, Ministry of Public Health, P.O. Box 14386, Yaoundé, Cameroon
| | - Jude D. Bigoga
- National Reference Unit for Vector Control, The Biotechnology Center, University of Yaoundé I, P.O. Box 3851-Messa, Yaoundé, Cameroon
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3
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Iovinella I, Caputo B, Calzetta M, Zwiebel LJ, Dani FR, Della Torre A. Profiles of soluble proteins in chemosensory organs of three members of the afro-tropical Anopheles gambiae complex. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2017; 24:41-50. [PMID: 28822866 DOI: 10.1016/j.cbd.2017.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/24/2017] [Accepted: 07/28/2017] [Indexed: 10/19/2022]
Abstract
In female mosquitoes, host-seeking and preference as well as several other important behaviors are largely driven by olfaction. Species of the Afrotropical Anopheles gambiae complex display divergent host-preference that are associated with significant differences in their vectorial capacity for human malaria. Olfactory sensitivity begins with signal transduction and activation of peripheral sensory neurons that populate the antennae, maxillary palps and other appendages. We have used shotgun proteomics to characterize the profile of soluble proteins of antennae and maxillary palps of three different species: An. coluzzii, An. arabiensis and An. quadriannulatus that display remarkable differences in anthropophilic behavior. This analysis revealed interspecific differences in the abundance of several proteins that comprise cuticular components, glutathione S-transferase and odorant binding proteins, the latter of which known to be directly involved in odor recognition.
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Affiliation(s)
- Immacolata Iovinella
- Biology Department, Università di Firenze, Italy; Department of Public Health & Infectious Diseases, Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, University of Rome "Sapienza", Rome, Italy
| | - Beniamino Caputo
- Department of Public Health & Infectious Diseases, Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, University of Rome "Sapienza", Rome, Italy
| | - Maria Calzetta
- Department of Public Health & Infectious Diseases, Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, University of Rome "Sapienza", Rome, Italy
| | - Laurence J Zwiebel
- Departments of Biological Sciences and Pharmacology, Vanderbilt University, Nashville, USA
| | - Francesca Romana Dani
- Biology Department, Università di Firenze, Italy; CISM, Mass Spectrometry Centre, Università di Firenze, Italy.
| | - Alessandra Della Torre
- Department of Public Health & Infectious Diseases, Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, University of Rome "Sapienza", Rome, Italy
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4
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St Laurent B, Cooke M, Krishnankutty SM, Asih P, Mueller JD, Kahindi S, Ayoma E, Oriango RM, Thumloup J, Drakeley C, Cox J, Collins FH, Lobo NF, Stevenson JC. Molecular Characterization Reveals Diverse and Unknown Malaria Vectors in the Western Kenyan Highlands. Am J Trop Med Hyg 2016; 94:327-35. [PMID: 26787150 DOI: 10.4269/ajtmh.15-0562] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 11/03/2015] [Indexed: 12/21/2022] Open
Abstract
The success of mosquito-based malaria control is dependent upon susceptible bionomic traits in local malaria vectors. It is crucial to have accurate and reliable methods to determine mosquito species composition in areas subject to malaria. An unexpectedly diverse set of Anopheles species was collected in the western Kenyan highlands, including unidentified and potentially new species carrying the malaria parasite Plasmodium falciparum. This study identified 2,340 anopheline specimens using both ribosomal DNA internal transcribed spacer region 2 and mitochondrial DNA cytochrome oxidase subunit 1 loci. Seventeen distinct sequence groups were identified. Of these, only eight could be molecularly identified through comparison to published and voucher sequences. Of the unidentified species, four were found to carry P. falciparum by circumsporozoite enzyme-linked immunosorbent assay and polymerase chain reaction, the most abundant of which had infection rates comparable to a primary vector in the area, Anopheles funestus. High-quality adult specimens of these unidentified species could not be matched to museum voucher specimens or conclusively identified using multiple keys, suggesting that they may have not been previously described. These unidentified vectors were captured outdoors. Diverse and unknown species have been incriminated in malaria transmission in the western Kenya highlands using molecular identification of unusual morphological variants of field specimens. This study demonstrates the value of using molecular methods to compliment vector identifications and highlights the need for accurate characterization of mosquito species and their associated behaviors for effective malaria control.
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Affiliation(s)
- Brandyce St Laurent
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Centre for Global Health Research, Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya; Western Triangle Research Center, Montana State University, Conrad, Montana; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Mary Cooke
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Centre for Global Health Research, Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya; Western Triangle Research Center, Montana State University, Conrad, Montana; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Sindhu M Krishnankutty
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Centre for Global Health Research, Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya; Western Triangle Research Center, Montana State University, Conrad, Montana; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Puji Asih
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Centre for Global Health Research, Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya; Western Triangle Research Center, Montana State University, Conrad, Montana; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - John D Mueller
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Centre for Global Health Research, Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya; Western Triangle Research Center, Montana State University, Conrad, Montana; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Samuel Kahindi
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Centre for Global Health Research, Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya; Western Triangle Research Center, Montana State University, Conrad, Montana; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Elizabeth Ayoma
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Centre for Global Health Research, Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya; Western Triangle Research Center, Montana State University, Conrad, Montana; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Robin M Oriango
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Centre for Global Health Research, Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya; Western Triangle Research Center, Montana State University, Conrad, Montana; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Julie Thumloup
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Centre for Global Health Research, Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya; Western Triangle Research Center, Montana State University, Conrad, Montana; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Chris Drakeley
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Centre for Global Health Research, Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya; Western Triangle Research Center, Montana State University, Conrad, Montana; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Jonathan Cox
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Centre for Global Health Research, Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya; Western Triangle Research Center, Montana State University, Conrad, Montana; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Frank H Collins
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Centre for Global Health Research, Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya; Western Triangle Research Center, Montana State University, Conrad, Montana; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Neil F Lobo
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Centre for Global Health Research, Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya; Western Triangle Research Center, Montana State University, Conrad, Montana; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Jennifer C Stevenson
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Centre for Global Health Research, Kenya Medical Research Institute/Centers for Disease Control and Prevention, Kisumu, Kenya; Western Triangle Research Center, Montana State University, Conrad, Montana; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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5
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Lobo NF, St Laurent B, Sikaala CH, Hamainza B, Chanda J, Chinula D, Krishnankutty SM, Mueller JD, Deason NA, Hoang QT, Boldt HL, Thumloup J, Stevenson J, Seyoum A, Collins FH. Unexpected diversity of Anopheles species in Eastern Zambia: implications for evaluating vector behavior and interventions using molecular tools. Sci Rep 2015; 5:17952. [PMID: 26648001 PMCID: PMC4673690 DOI: 10.1038/srep17952] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 11/09/2015] [Indexed: 11/21/2022] Open
Abstract
The understanding of malaria vector species in association with their bionomic traits is vital for targeting malaria interventions and measuring effectiveness. Many entomological studies rely on morphological identification of mosquitoes, limiting recognition to visually distinct species/species groups. Anopheles species assignments based on ribosomal DNA ITS2 and mitochondrial DNA COI were compared to morphological identifications from Luangwa and Nyimba districts in Zambia. The comparison of morphological and molecular identifications determined that interpretations of species compositions, insecticide resistance assays, host preference studies, trap efficacy, and Plasmodium infections were incorrect when using morphological identification alone. Morphological identifications recognized eight Anopheles species while 18 distinct sequence groups or species were identified from molecular analyses. Of these 18, seven could not be identified through comparison to published sequences. Twelve of 18 molecularly identified species (including unidentifiable species and species not thought to be vectors) were found by PCR to carry Plasmodium sporozoites - compared to four of eight morphological species. Up to 15% of morphologically identified Anopheles funestus mosquitoes in insecticide resistance tests were found to be other species molecularly. The comprehension of primary and secondary malaria vectors and bionomic characteristics that impact malaria transmission and intervention effectiveness are fundamental in achieving malaria elimination.
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Affiliation(s)
- Neil F Lobo
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA 46556
| | - Brandyce St Laurent
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA 46556
| | - Chadwick H Sikaala
- National Malaria Control Centre, Chainama Hospital College Grounds, Off Great East road, P.O. Box 32509, Lusaka, Zambia
| | - Busiku Hamainza
- National Malaria Control Centre, Chainama Hospital College Grounds, Off Great East road, P.O. Box 32509, Lusaka, Zambia
| | - Javan Chanda
- National Malaria Control Centre, Chainama Hospital College Grounds, Off Great East road, P.O. Box 32509, Lusaka, Zambia
| | - Dingani Chinula
- National Malaria Control Centre, Chainama Hospital College Grounds, Off Great East road, P.O. Box 32509, Lusaka, Zambia
| | | | - Jonathan D Mueller
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA 46556
| | - Nicholas A Deason
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA 46556
| | - Quynh T Hoang
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA 46556
| | - Heather L Boldt
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA 46556
| | - Julie Thumloup
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA 46556
| | - Jennifer Stevenson
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.; and Macha Research Trust, Choma, Zambia
| | - Aklilu Seyoum
- Abt Associates, Africa Indoor Residual Spraying Project Ghana office, Accra, Ghana
| | - Frank H Collins
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA 46556
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Seyoum A, Sikaala CH, Chanda J, Chinula D, Ntamatungiro AJ, Hawela M, Miller JM, Russell TL, Briët OJT, Killeen GF. Human exposure to anopheline mosquitoes occurs primarily indoors, even for users of insecticide-treated nets in Luangwa Valley, South-east Zambia. Parasit Vectors 2012; 5:101. [PMID: 22647493 PMCID: PMC3432592 DOI: 10.1186/1756-3305-5-101] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Accepted: 05/23/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Current front line malaria vector control methods such as indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs), rely upon the preference of many primary vectors to feed and/or rest inside human habitations where they can be targeted with domestically-applied insecticidal products. We studied the human biting behaviour of the malaria vector Anopheles funestus Giles and the potential malaria vector Anopheles quadriannulatus Theobald in Luangwa valley, south-east Zambia. METHODS Mosquitoes were collected by human landing catch in blocks of houses with either combined use of deltamethrin-based IRS and LLINs or LLINs alone. Human behaviour data were collected to estimate how much exposure to mosquito bites indoors and outdoors occurred at various times of the night for LLIN users and non-users. RESULTS Anopheles funestus and An. quadriannulatus did not show preference to bite either indoors or outdoors: the proportions [95% confidence interval] caught indoors were 0.586 [0.303, 0.821] and 0.624 [0.324, 0.852], respectively. However, the overwhelming majority of both species were caught at times when most people are indoors. The proportion of mosquitoes caught at a time when most people are indoors were 0.981 [0.881, 0.997] and 0.897 [0.731, 0.965], respectively, so the proportion of human exposure to both species occuring indoors was high for individuals lacking LLINs (An. funestus: 0.983 and An. quadriannulatus: 0.970, respectively). While LLIN users were better protected, more than half of their exposure was nevertheless estimated to occur indoors (An. funestus: 0.570 and An. quadriannulatus: 0.584). CONCLUSIONS The proportion of human exposure to both An. funestus and An. quadriannulatus occuring indoors was high in the area and hence both species might be responsive to further peri-domestic measures if these mosquitoes are susceptible to insecticidal products.
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Affiliation(s)
- Aklilu Seyoum
- Liverpool School of Tropical Medicine, Vector Group, Pembroke Place, Liverpool, L3 5QA, UK
| | - Chadwick H Sikaala
- Liverpool School of Tropical Medicine, Vector Group, Pembroke Place, Liverpool, L3 5QA, UK
- National Malaria Control Centre, PO Box 32509, Lusaka, Zambia
| | - Javan Chanda
- National Malaria Control Centre, PO Box 32509, Lusaka, Zambia
| | - Dingani Chinula
- National Malaria Control Centre, PO Box 32509, Lusaka, Zambia
| | - Alex J Ntamatungiro
- Ifakara Health Institute, Biomedical and Environmental Thematic Group, Kiko Avenue, PO Box 78373, Dar es Salaam, Tanzania
| | - Moonga Hawela
- National Malaria Control Centre, PO Box 32509, Lusaka, Zambia
| | - John M Miller
- PATH Malaria Control and Evaluation Partnership in Africa (MACEPA), National Malaria Control Centre, Lusaka, Zambia
| | - Tanya L Russell
- Liverpool School of Tropical Medicine, Vector Group, Pembroke Place, Liverpool, L3 5QA, UK
- Ifakara Health Institute, Biomedical and Environmental Thematic Group, Kiko Avenue, PO Box 78373, Dar es Salaam, Tanzania
- James Cook University, Faculty of Medicine, Health and Molecular Sciences, Cairns, Australia
| | - Olivier J T Briët
- Swiss Tropical and Public Health Institute, Department of Public Health and Epidemiology, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Gerry F Killeen
- Liverpool School of Tropical Medicine, Vector Group, Pembroke Place, Liverpool, L3 5QA, UK
- Ifakara Health Institute, Biomedical and Environmental Thematic Group, Kiko Avenue, PO Box 78373, Dar es Salaam, Tanzania
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7
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Habtewold T, Povelones M, Blagborough AM, Christophides GK. Transmission blocking immunity in the malaria non-vector mosquito Anopheles quadriannulatus species A. PLoS Pathog 2008; 4:e1000070. [PMID: 18497855 PMCID: PMC2374904 DOI: 10.1371/journal.ppat.1000070] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Accepted: 04/14/2008] [Indexed: 01/26/2023] Open
Abstract
Despite being phylogenetically very close to Anopheles gambiae, the major mosquito vector of human malaria in Africa, Anopheles quadriannulatus is thought to be a non-vector. Understanding the difference between vector and non-vector mosquitoes can facilitate development of novel malaria control strategies. We demonstrate that An. quadriannulatus is largely resistant to infections by the human parasite Plasmodium falciparum, as well as by the rodent parasite Plasmodium berghei. By using genetics and reverse genetics, we show that resistance is controlled by quantitative heritable traits and manifested by lysis or melanization of ookinetes in the mosquito midgut, as well as by killing of parasites at subsequent stages of their development in the mosquito. Genes encoding two leucine-rich repeat proteins, LRIM1 and LRIM2, and the thioester-containing protein, TEP1, are identified as essential in these immune reactions. Their silencing completely abolishes P. berghei melanization and dramatically increases the number of oocysts, thus transforming An. quadriannulatus into a highly permissive parasite host. We hypothesize that the mosquito immune system is an important cause of natural refractoriness to malaria and that utilization of this innate capacity of mosquitoes could lead to new methods to control transmission of the disease. Malaria is a mosquito-borne infectious disease that threatens almost half of the human population and kills 1 to 3 million people every year. In sub-Saharan Africa, where the vast majority of deaths occur, the capacity of mosquitoes to transmit malaria varies greatly even between closely related species. We compared the ability of malaria parasites to develop in two very closely related mosquitoes, one vector and one non-vector, and found that non-vector mosquitoes kill parasites at various stages, predominantly when they invade the mosquito midgut. This is achieved by parasite clearance, possibly by lysis in the midgut cells and by melanization, both of which are reactions of the mosquito immune system. This phenotype depends on heritable and dominant traits that can be passed on to vector/non-vector mosquito hybrids. We examined whether specific components of the mosquito immune system affect the resistance of these mosquitoes to infection. By silencing the activity of three immunity genes, we transformed mosquitoes of the resistant species into highly susceptible. Our results suggest that the mosquito immune system may affect refractoriness to malaria in non-vector mosquitoes. This innate capacity of mosquitoes to kill malaria parasites could be utilized in future integrated efforts to control and ultimately eradicate the disease.
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Affiliation(s)
- Tibebu Habtewold
- Immunology and Infection, Division of Cell and Molecular Biology, Faculty of Natural Sciences, Imperial College London, London, United Kingdom
| | - Michael Povelones
- Immunology and Infection, Division of Cell and Molecular Biology, Faculty of Natural Sciences, Imperial College London, London, United Kingdom
| | - Andrew M. Blagborough
- Immunology and Infection, Division of Cell and Molecular Biology, Faculty of Natural Sciences, Imperial College London, London, United Kingdom
| | - George K. Christophides
- Immunology and Infection, Division of Cell and Molecular Biology, Faculty of Natural Sciences, Imperial College London, London, United Kingdom
- * E-mail:
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