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Moustapha LM, Sadou IM, Arzika II, Maman LI, Gomgnimbou MK, Konkobo M, Diabate A, Bilgo E. First identification of Microsporidia MB in Anopheles coluzzii from Zinder City, Niger. Parasit Vectors 2024; 17:39. [PMID: 38287334 PMCID: PMC10826271 DOI: 10.1186/s13071-023-06059-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 11/15/2023] [Indexed: 01/31/2024] Open
Abstract
BACKGROUND Malaria, a disease transmitted by Anopheles mosquitoes, is a major public health problem causing millions of deaths worldwide, mostly among children under the age of 5 years. Biotechnological interventions targeting parasite-vector interactions have shown that the microsporidian symbiont Microsporidia MB has the potential to disrupt and block Plasmodium transmission. METHODS A prospective cross-sectional survey was conducted in Zinder City (Zinder), Niger, from August to September 2022, using the CDC light trap technique to collect adult mosquitoes belonging to the Anopheles gambiae complex. The survey focused on collecting mosquitoes from three neighborhoods of Zinder (Birni, Kangna and Garin Malan, located in communes I, II and IV, respectively). Collected mosquitoes were sorted and preserved in 70% ethanol. PCR was used to identify host species and detect the presence of Microsporidia MB and Plasmodium falciparum infection. RESULTS Of the 257 Anopheles mosquitoes collected and identified by PCR, Anopheles coluzzii was the most prevalent species, accounting for 97.7% of the total. Microsporidia MB was exclusively detected in A. coluzzii, with a prevalence of 6.8% (17/251) among the samples. No significant difference in prevalence was found among the three neighborhoods. Only one An. coluzzii mosquito tested PCR-positive for P. falciparum. CONCLUSIONS The results confirm the presence of Microsporidia MB in Anopheles mosquitoes in Zinder, Niger, indicating its potential use as a biotechnological intervention against malaria transmission. However, further studies are needed to determine the efficacy of Microsporidia MB to disrupt Plasmodium transmission as well as its impact on vector fitness.
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Affiliation(s)
- Lamine Mahaman Moustapha
- Faculté de Sciences et Techniques de l'Université André Salifou, Zinder, Niger.
- Centre de Recherche Médicale et Sanitaire (CERMES), Niamey, Niger.
| | - Illiassou Mamane Sadou
- Centre d'Excellence Africain en Innovations Biotechnologiques pour l'Elimination des Maladies à Transmission Vectorielle (CEA/ITECH-MTV), Université Nazi Boni (UNB), Bobo Dioulasso, Burkina Faso
| | | | | | - Michel K Gomgnimbou
- Centre d'Excellence Africain en Innovations Biotechnologiques pour l'Elimination des Maladies à Transmission Vectorielle (CEA/ITECH-MTV), Université Nazi Boni (UNB), Bobo Dioulasso, Burkina Faso
- Centre Muraz, Institut National de Santé Publique (INSP), Bobo Dioulasso, Burkina Faso
| | - Maurice Konkobo
- Centre d'Excellence Africain en Innovations Biotechnologiques pour l'Elimination des Maladies à Transmission Vectorielle (CEA/ITECH-MTV), Université Nazi Boni (UNB), Bobo Dioulasso, Burkina Faso
- Centre Muraz, Institut National de Santé Publique (INSP), Bobo Dioulasso, Burkina Faso
- Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest, Bobo Dioulasso, Burkina Faso
| | - Abdoulaye Diabate
- Centre d'Excellence Africain en Innovations Biotechnologiques pour l'Elimination des Maladies à Transmission Vectorielle (CEA/ITECH-MTV), Université Nazi Boni (UNB), Bobo Dioulasso, Burkina Faso
- Centre Muraz, Institut National de Santé Publique (INSP), Bobo Dioulasso, Burkina Faso
- Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest, Bobo Dioulasso, Burkina Faso
| | - Etienne Bilgo
- Centre d'Excellence Africain en Innovations Biotechnologiques pour l'Elimination des Maladies à Transmission Vectorielle (CEA/ITECH-MTV), Université Nazi Boni (UNB), Bobo Dioulasso, Burkina Faso.
- Centre Muraz, Institut National de Santé Publique (INSP), Bobo Dioulasso, Burkina Faso.
- Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest, Bobo Dioulasso, Burkina Faso.
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Pichler V, Sanou A, Love RR, Caputo B, Pombi M, Toe KH, Guelbeogo MW, Sagnon N, Ferguson HM, Ranson H, Torre AD, Besansky NJ. A novel tetra-primer ARMS-PCR approach for the molecular karyotyping of chromosomal inversion 2Ru in the main malaria vectors Anopheles gambiae and Anopheles coluzzii. Parasit Vectors 2023; 16:388. [PMID: 37891582 PMCID: PMC10605393 DOI: 10.1186/s13071-023-06014-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 10/14/2023] [Indexed: 10/29/2023] Open
Abstract
BACKGROUND Chromosomal inversion polymorphisms have been associated with adaptive behavioral, physiological, morphological and life history traits in the two main Afrotropical malaria vectors, Anopheles coluzzii and Anopheles gambiae. The understanding of the adaptive value of chromosomal inversion systems is constrained by the feasibility of cytological karyotyping. In recent years in silico and molecular approaches have been developed for the genotyping of most widespread inversions (2La, 2Rb and 2Rc). The 2Ru inversion, spanning roughly 8% of chromosome 2R, is commonly polymorphic in West African populations of An. coluzzii and An. gambiae and shows clear increases in frequency with increasing rainfall seasonally and geographically. The aim of this work was to overcome the constraints of currently available cytological and high-throughput molecular assays by developing a simple PCR assay for genotyping the 2Ru inversion in individual specimens of both mosquito species. METHODS We designed tetra-primer amplification refractory mutation system (ARMS)-PCR assays based on five tag single-nucleotide polymorphisms (SNPs) previously shown to be strongly correlated with 2Ru inversion orientation. The most promising assay was validated against laboratory and field samples of An. coluzzii and An. gambiae karyotyped either cytogenetically or molecularly using a genotyping-in-thousands by sequencing (GT-seq) high-throughput approach that employs targeted sequencing of multiplexed PCR amplicons. RESULTS A successful assay was designed based on the tag SNP at position 2R, 31710303, which is highly predictive of the 2Ru genotype. The assay, which requires only one PCR, and no additional post-PCR processing other than electrophoresis, produced a clear banding pattern for 98.5% of the 454 specimens tested, which is a 96.7% agreement with established karyotyping methods. Sequences were obtained for nine of the An. coluzzii specimens manifesting 2Ru genotype discrepancies with GT-seq. Possible sources of these discordances are discussed. CONCLUSIONS The tetra-primer ARMS-PCR assay represents an accurate, streamlined and cost-effective method for the molecular karyotyping of the 2Ru inversion in An. coluzzii and An. gambiae. Together with approaches already available for the other common polymorphic inversions, 2La, 2Rb and 2Rc, this assay will allow investigations of the adaptive value of the complex set of inversion systems observed in the two major malaria vectors in the Afrotropical region.
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Affiliation(s)
- Verena Pichler
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur-Fondazione Cenci-Bolognetti, Università "La Sapienza", 00185, Rome, Italy.
| | - Antoine Sanou
- Centre National de Recherche et de Formation Sur le Paludisme, Ouagadougou, Burkina Faso
- Institute of Biodiversity, Animal Health & Comparative Medicine, Glasgow University, Glasgow, G128QQ, UK
| | - R Rebecca Love
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
- Entomology Branch, Division of Parasitic Diseases and Malaria, U.S. Centers for Disease Control and Prevention (CDC), Atlanta, GA, 30333, USA
| | - Beniamino Caputo
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur-Fondazione Cenci-Bolognetti, Università "La Sapienza", 00185, Rome, Italy
| | - Marco Pombi
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur-Fondazione Cenci-Bolognetti, Università "La Sapienza", 00185, Rome, Italy
| | - Kobie Hyacinth Toe
- Centre National de Recherche et de Formation Sur le Paludisme, Ouagadougou, Burkina Faso
| | - Moussa W Guelbeogo
- Centre National de Recherche et de Formation Sur le Paludisme, Ouagadougou, Burkina Faso
| | - N'Fale Sagnon
- Centre National de Recherche et de Formation Sur le Paludisme, Ouagadougou, Burkina Faso
| | - Heather M Ferguson
- Institute of Biodiversity, Animal Health & Comparative Medicine, Glasgow University, Glasgow, G128QQ, UK
| | - Hilary Ranson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Alessandra Della Torre
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur-Fondazione Cenci-Bolognetti, Università "La Sapienza", 00185, Rome, Italy
| | - Nora J Besansky
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA.
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Coulibaly YI, Sangare M, Dolo H, Soumaoro L, Coulibaly SY, Dicko I, Diabaté AF, Diarra L, Coulibaly ME, Doumbia SS, Diallo AA, Dembele M, Koudou BG, Bockarie MJ, Kelly-Hope LA, Klion AD, Nutman TB. No evidence of lymphatic filariasis transmission in Bamako urban setting after three mass drug administration rounds. Parasitol Res 2022; 121:3243-3248. [PMID: 36066741 PMCID: PMC9556341 DOI: 10.1007/s00436-022-07648-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 08/30/2022] [Indexed: 11/25/2022]
Abstract
Lymphatic filariasis (LF) elimination activities started in Mali in 2005 in the most endemic areas and reached countrywide coverage in 2009. In 2004, the district of Bamako was endemic for LF with a prevalence of 1.5%. The current study was designed to determine LF endemicity level in the urban area of Bamako after three rounds of ivermectin and albendazole mass drug administration (MDA). A cross-sectional study was conducted in 2011 in Bamako city, consisting of human prevalence and entomological surveys. Volunteers aged 14 years and above were invited to participate and tested for evidence of Wuchereria bancrofti using night time blood thick smear microfilarial count and blood spots for LF antibodies using the SD BIOLINE Oncho/LF IgG4 Biplex rapid test (Ov16/Wb123). Mosquitoes were collected using CDC light and gravid traps and tested using molecular methods. Poolscreen software v2.0 was used to estimate vector transmission potential. Of the 899 volunteers, one (0.11%) was found to be positive for LF using the Oncho/LF IgG4 Biplex rapid test, and none was found to have Wuchereria bancrofti microfilariae. No mosquitoes were found infected among 6174 Culex spp. (85.2%), 16 Anopheles gambiae s.l. (An. gambiae s.l.) (0.2%), 26 Aedes spp. (0.4%), 858 Ceratopogonidae (11.8%) and 170 other insects not identified (2.3%) tested. Our data indicate that there was no active LF transmission in the low prevalence urban district of Bamako after three MDA rounds. These data helped the National LF programme move forward towards the elimination goal.
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Affiliation(s)
- Yaya Ibrahim Coulibaly
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali.,Dermatology Hospital of Bamako, Bamako, Mali
| | - Moussa Sangare
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali. .,Interdisciplinary School of Health Sciences
- Faculty of Health Sciences, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
| | - Housseini Dolo
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Lamine Soumaoro
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Siaka Yamoussa Coulibaly
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Ilo Dicko
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Abdoul Fatao Diabaté
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Lamine Diarra
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Michel Emmanuel Coulibaly
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Salif Seriba Doumbia
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Abdallah Amadou Diallo
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Massitan Dembele
- National Lymphatic Filariasis Elimination Program, Ministry of Health and Public Hygiene, Bamako, Mali
| | - Benjamin G Koudou
- Centre Suisse de Recherche Scientifiques en Côte d'Ivoire, 01 BP 1303 Abidjan 01, Abidjan, Côte d'Ivoire.,UFR Science de la Nature, Université Nangui Abrogoua, 02 BP 801 Abidjan 01, Abidjan, Côte d'Ivoire
| | | | - Louise A Kelly-Hope
- Centre for Neglected Tropical Diseases, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK.,Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Amy D Klion
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Thomas B Nutman
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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Boussougou-Sambe ST, Woldearegai TG, Doumba-Ndalembouly AG, Ngossanga B, Mba RB, Edoa JR, Zinsou JF, Honkpehedji YJ, Ngoa UA, Dejon-Agobé JC, Borrmann S, Kremsner PG, Mordmüller B, Adegnika AA. Assessment of malaria transmission intensity and insecticide resistance mechanisms in three rural areas of the Moyen Ogooué Province of Gabon. Parasit Vectors 2022; 15:217. [PMID: 35725630 PMCID: PMC9208124 DOI: 10.1186/s13071-022-05320-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 05/10/2022] [Indexed: 12/03/2022] Open
Abstract
Background Vector control is considered to be the most successful component of malaria prevention programs and a major contributor to the reduction of malaria incidence over the last two decades. However, the success of this strategy is threatened by the development of resistance to insecticides and behavioural adaptations of vectors. The aim of this study was to monitor malaria transmission and the distribution of insecticide resistance genes in Anopheles populations from three rural areas of the Moyen Ogooué Province of Gabon. Methods Anopheles spp. were collected using human landing catches in Bindo, Nombakélé and Zilé, three villages located in the surroundings of Lambaréné, during both the rainy and dry seasons. Mosquitoes were identified morphologically, and DNA was extracted from heads and thoraces. Members of the Anopheles gambiae complex were identified by molecular methods using the PCR SINE200 protocol and by sequencing of the internal transcribed spacer 2 region. Taqman assays were used to determine Plasmodium infection and the presence of resistance alleles. Results Anopheles gambiae sensu lato (97.7%), An. moucheti (1.7%) and An. coustani (0.6%) were the three groups of species collected. Anopheles gambiae sensu stricto (98.5%) and An. coluzzii (1.5%) were the only species of the An. gambiae complex present in the collection. Of the 1235 Anopheles collected, 1193 were collected during the rainy season; these exhibited an exophagic behaviour, and consistently more mosquitoes were collected outdoor than indoor in the three study areas. Of the 1166 Anopheles screened, 26 (2.2%) were infected with Plasmodium species, specifically Plasmodium falciparum (66.7%), P. malariae (15.4%), P. ovale curtisi (11.5%) and P. ovale wallikeri (3.8%). Malaria transmission intensity was high in Zilé, with an average annual entomological inoculation rate (aEIR) of 243 infective bites per year, while aEIRs in Bindo and Nombakélé were 80.2 and 17 infective bites per year, respectively. Both the L1014F and L1014S mutations were present at frequencies > 95% but no Ace1G119S mutation was found. Conclusion Our results demonstrate that malaria transmission intensity is heterogeneous in these three rural areas of Moyen Ogooué Province, with areas of high transmission, such as Zilé. The exophagic behaviour of the mosquitoes as well as the high frequency of resistance mutations are serious challenges that need to be addressed by the deployment of control measures adapted to the local setting. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05320-9.
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Affiliation(s)
| | - Tamirat Gebru Woldearegai
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Eberhard Karls Universität, Tübingen, Germany.,German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | | | | | - Romuald Beh Mba
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | | | - Jeannot Fréjus Zinsou
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
| | - Yabo Josiane Honkpehedji
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands.,Fondation pour la Recherche Scientifique (FORS), Cotonou, Benin
| | | | - Jean Claude Dejon-Agobé
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Academic Medical Center (AMC), University of Amsterdam, Amsterdam, the Netherlands
| | - Steffen Borrmann
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Eberhard Karls Universität, Tübingen, Germany
| | - Peter G Kremsner
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Eberhard Karls Universität, Tübingen, Germany.,German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Benjamin Mordmüller
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Eberhard Karls Universität, Tübingen, Germany.,Department of Medical Microbiology, Radboud University Medical Center (UMC), 6524 GA, Nijmegen, The Netherlands
| | - Ayôla A Adegnika
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,Institut für Tropenmedizin, Eberhard Karls Universität, Tübingen, Germany.,German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany.,Fondation pour la Recherche Scientifique (FORS), Cotonou, Benin
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Caputo B, Tondossoma N, Virgillito C, Pichler V, Serini P, Calzetta M, Manica M, Coulibaly ZI, Dia I, Akré M, Offianan A, Della Torre A. Is Côte D'Ivoire a new high hybridization zone for the two major malaria vectors, Anopheles coluzzii and An. gambiae (Diptera, Culicidae)? Infect Genet Evol 2022; 98:105215. [PMID: 35063691 DOI: 10.1016/j.meegid.2022.105215] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [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: 08/20/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 06/14/2023]
Abstract
Anopheles gambiae and An. coluzzii are very closely related and recently differentiated species representing the main malaria vectors in the Afrotropical region and responsible of up to >3 infective bites/person/night in Côte D'Ivoire, where prevention and control has stagnated in recent years. The aim of the present study was to genetically and ecologically characterize An. gambiae and An. coluzzii populations from two villages of Côte D'Ivoire, lying in the coastal forest belt and 250 km inland in the Guinean savannah mosaic belt, respectively. Results reveal high frequencies of both species in both study sites and high frequencies of hybrids (4-33%) along the whole year of sampling. Consistently with observations for the well-known high hybridization zone at the far-west of the species range, hybrid frequencies were higher in the coastal village and highest when the two species occurred at more balanced frequencies, supporting the "frequency-dependent hybridization" ecological speciation theory. Pilot genotyping revealed signatures of genomic admixture in both chromosome-X and -3. Coupled with previous reports of hybrids in the region, the results point to the coastal region of Côte D'Ivoire as a possible regions of high hybridization. Preliminary characterization of parameters relevant for malaria transmission and control (e.g. possibly higher sporozoite rates and indoor biting preferences in hybrids than in the parental species) highlight the possible relevance of the breakdown of reproductive barriers between An. gambiae and An. coluzzii not only in the field of ecological evolution, but also in malaria epidemiology and control.
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Affiliation(s)
- Beniamino Caputo
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "La Sapienza", Piazzale Aldo Moro, 5, 00185 Rome, Italy.
| | - Naminata Tondossoma
- Unité de Paludologie, Institut Pasteur de Côte D'Ivoire, Abidjan, Côte D'Ivoire; Institut Pierre Richet/Institut National de Santé Publique, Bouaké, Côte D'Ivoire
| | - Chiara Virgillito
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "La Sapienza", Piazzale Aldo Moro, 5, 00185 Rome, Italy; Unité de Paludologie, Institut Pasteur de Côte D'Ivoire, Abidjan, Côte D'Ivoire; Institut Pierre Richet/Institut National de Santé Publique, Bouaké, Côte D'Ivoire; Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, TN, Italy
| | - Verena Pichler
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "La Sapienza", Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - Paola Serini
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "La Sapienza", Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - Maria Calzetta
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "La Sapienza", Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - Mattia Manica
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, TN, Italy; Center for Health Emergencies, Bruno Kessler Foundation, Trento, Italy
| | | | - Ibrahima Dia
- Unité d'entomologie médicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, Dakar, BP 220, Senegal
| | - Maurice Akré
- Institut Pierre Richet/Institut National de Santé Publique, Bouaké, Côte D'Ivoire
| | - Andre Offianan
- Unité de Paludologie, Institut Pasteur de Côte D'Ivoire, Abidjan, Côte D'Ivoire
| | - Alessandra Della Torre
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur Italia-Fondazione Cenci-Bolognetti, Università di Roma "La Sapienza", Piazzale Aldo Moro, 5, 00185 Rome, Italy
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6
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Ngom EHM, Virgillito C, Manica M, Rosà R, Pichler V, Sarleti N, Kassé I, Diallo M, della Torre A, Dia I, Caputo B. Entomological Survey Confirms Changes in Mosquito Composition and Abundance in Senegal and Reveals Discrepancies among Results by Different Host-Seeking Female Traps. Insects 2021; 12:692. [PMID: 34442258 PMCID: PMC8396443 DOI: 10.3390/insects12080692] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/26/2021] [Accepted: 07/28/2021] [Indexed: 11/16/2022]
Abstract
Mosquitoes-borne diseases are major public health issues particularly in Africa. Vector control interventions and human-made environmental/climatic changes significantly affect the distribution and abundance of vector species. We carried out an entomological survey targeting host-seeking mosquitos in two different ecological contexts-coastal and inland-in Senegal, by CDC-light and BG-sentinel traps. Results show high predominance of Culex quinquefasciatus (90%) and of Anopheles arabiensis within malaria vectors (46%), with mean numbers of females/trap/nights =8 and <1, respectively, reinforcing previous evidence of changes in species composition and abundance, highlighting thus increasing risk of transmission of filariasis and emerging arboviruses in the Senegambia region. From the methodological perspective, results show a higher specificity of BG traps for Cx. quinquefasciatus and of CDC traps for An. gambiae s.l. and highlight that, despite both traps target the host-seeking fraction of the population, they provide different patterns of species abundance, temporal dynamics and host-seeking activity, leading to possible misinterpretation of the species bionomics. This draws attention to the need of taking into account trapping performance, in order to provide realistic quantification of the number of mosquitoes per units of space and time, the crucial parameter for evaluating vector-human contact, and estimating risk of pathogen transmission.
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Affiliation(s)
- El Hadji Malick Ngom
- Medical Zoology Pole, Institut Pasteur de Dakar, Dakar 12500, Senegal; (E.H.M.N.); (I.K.); (M.D.)
| | - Chiara Virgillito
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy; (C.V.); (V.P.); (N.S.); (A.d.T.)
- Department of Biodiversity and Molecular Ecology, Edmund Mach Foundation, 38098 San Michele all’Adige, Italy; (M.M.); (R.R.)
| | - Mattia Manica
- Department of Biodiversity and Molecular Ecology, Edmund Mach Foundation, 38098 San Michele all’Adige, Italy; (M.M.); (R.R.)
- Center for Health Emergencies, Bruno Kessler Foundation, 380123 Trento, Italy
| | - Roberto Rosà
- Department of Biodiversity and Molecular Ecology, Edmund Mach Foundation, 38098 San Michele all’Adige, Italy; (M.M.); (R.R.)
- Center Agriculture Food Environment, University of Trento, 38098 San Michele all’Adige, Italy
| | - Verena Pichler
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy; (C.V.); (V.P.); (N.S.); (A.d.T.)
| | - Noemi Sarleti
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy; (C.V.); (V.P.); (N.S.); (A.d.T.)
| | - Isseu Kassé
- Medical Zoology Pole, Institut Pasteur de Dakar, Dakar 12500, Senegal; (E.H.M.N.); (I.K.); (M.D.)
| | - Mawlouth Diallo
- Medical Zoology Pole, Institut Pasteur de Dakar, Dakar 12500, Senegal; (E.H.M.N.); (I.K.); (M.D.)
| | - Alessandra della Torre
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy; (C.V.); (V.P.); (N.S.); (A.d.T.)
| | - Ibrahima Dia
- Medical Zoology Pole, Institut Pasteur de Dakar, Dakar 12500, Senegal; (E.H.M.N.); (I.K.); (M.D.)
| | - Beniamino Caputo
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy; (C.V.); (V.P.); (N.S.); (A.d.T.)
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7
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Montanez-Gonzalez R, Vallera AC, Calzetta M, Pichler V, Love RR, Guelbeogo MW, Dabire RK, Pombi M, Costantini C, Simard F, Della Torre A, Besansky NJ. A PCR-RFLP method for genotyping of inversion 2Rc in Anopheles coluzzii. Parasit Vectors 2021; 14:174. [PMID: 33752733 PMCID: PMC7983089 DOI: 10.1186/s13071-021-04657-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 01/13/2021] [Accepted: 02/23/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Genotyping of polymorphic chromosomal inversions in malaria vectors such as An. coluzzii Coetzee & Wilkerson is important, both because they cause cryptic population structure that can mislead vector analysis and control and because they influence epidemiologically relevant eco-phenotypes. The conventional cytogenetic method of genotyping is an impediment because it is labor intensive, requires specialized training, and can be applied only to one gender and developmental stage. Here, we circumvent these limitations by developing a simple and rapid molecular method of genotyping inversion 2Rc in An. coluzzii that is both economical and field-friendly. This inversion is strongly implicated in temporal and spatial adaptations to climatic and ecological variation, particularly aridity. METHODS Using a set of tag single-nucleotide polymorphisms (SNPs) strongly correlated with inversion orientation, we identified those that overlapped restriction enzyme recognition sites and developed four polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) assays that distinguish alternative allelic states at the tag SNPs. We assessed the performance of these assays using mosquito population samples from Burkina Faso that had been cytogenetically karyotyped as well as genotyped, using two complementary high-throughput molecular methods based on tag SNPs. Further validation was performed using mosquito population samples from additional West African (Benin, Mali, Senegal) and Central African (Cameroon) countries. RESULTS Of four assays tested, two were concordant with the 2Rc cytogenetic karyotype > 90% of the time in all samples. We recommend that these two assays be employed in tandem for reliable genotyping. By accepting only those genotypic assignments where both assays agree, > 99% of assignments are expected to be accurate. CONCLUSIONS We have developed tandem PCR-RFLP assays for the accurate genotyping of inversion 2Rc in An. coluzzii. Because this approach is simple, inexpensive, and requires only basic molecular biology equipment, it is widely accessible. These provide a crucial tool for probing the molecular basis of eco-phenotypes relevant to malaria epidemiology and vector control.
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Affiliation(s)
- Raquel Montanez-Gonzalez
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Alexandra C Vallera
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Maria Calzetta
- Dipartimento di Sanità Pubblica e Malattie Infettive, Università "La Sapienza", Istituto Pasteur-Fondazione Cenci-Bolognetti, 00185, Rome, Italy
| | - Verena Pichler
- Dipartimento di Sanità Pubblica e Malattie Infettive, Università "La Sapienza", Istituto Pasteur-Fondazione Cenci-Bolognetti, 00185, Rome, Italy
| | - Rachel R Love
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Moussa W Guelbeogo
- Centre National de Recherche et Formation sur Le Paludisme (CNRFP), Ouagadougou, Burkina Faso
| | - Roch K Dabire
- Institut de Recherche en Sciences de la Santé (IRSS)/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Marco Pombi
- Dipartimento di Sanità Pubblica e Malattie Infettive, Università "La Sapienza", Istituto Pasteur-Fondazione Cenci-Bolognetti, 00185, Rome, Italy
| | - Carlo Costantini
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
| | - Frederic Simard
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
| | - Alessandra Della Torre
- Dipartimento di Sanità Pubblica e Malattie Infettive, Università "La Sapienza", Istituto Pasteur-Fondazione Cenci-Bolognetti, 00185, Rome, Italy
| | - Nora J Besansky
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA.
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8
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Kranjc N, Crisanti A, Nolan T, Bernardini F. Anopheles gambiae Genome Conservation as a Resource for Rational Gene Drive Target Site Selection. Insects 2021; 12:97. [PMID: 33498790 PMCID: PMC7911984 DOI: 10.3390/insects12020097] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 12/15/2022]
Abstract
The increase in molecular tools for the genetic engineering of insect pests and disease vectors, such as Anopheles mosquitoes that transmit malaria, has led to an unprecedented investigation of the genomic landscape of these organisms. The understanding of genome variability in wild mosquito populations is of primary importance for vector control strategies. This is particularly the case for gene drive systems, which look to introduce genetic traits into a population by targeting specific genomic regions. Gene drive targets with functional or structural constraints are highly desirable as they are less likely to tolerate mutations that prevent targeting by the gene drive and consequent failure of the technology. In this study we describe a bioinformatic pipeline that allows the analysis of whole genome data for the identification of highly conserved regions that can point at potential functional or structural constraints. The analysis was conducted across the genomes of 22 insect species separated by more than hundred million years of evolution and includes the observed genomic variation within field caught samples of Anopheles gambiae and Anopheles coluzzii, the two most dominant malaria vectors. This study offers insight into the level of conservation at a genome-wide scale as well as at per base-pair resolution. The results of this analysis are gathered in a data storage system that allows for flexible extraction and bioinformatic manipulation. Furthermore, it represents a valuable resource that could provide insight into population structure and dynamics of the species in the complex and benefit the development and implementation of genetic strategies to tackle malaria.
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Affiliation(s)
- Nace Kranjc
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK; (N.K.); (A.C.)
| | - Andrea Crisanti
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK; (N.K.); (A.C.)
| | - Tony Nolan
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Federica Bernardini
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK; (N.K.); (A.C.)
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9
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Deitz KC, Takken W, Slotman MA. The Genetic Architecture of Post-Zygotic Reproductive Isolation Between Anopheles coluzzii and An. quadriannulatus. Front Genet 2020; 11:925. [PMID: 33005168 PMCID: PMC7480394 DOI: 10.3389/fgene.2020.00925] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 07/24/2020] [Indexed: 11/15/2022] Open
Abstract
The Anopheles gambiae complex is comprised of eight morphologically indistinguishable species and has emerged as a model system for the study of speciation genetics due to the rapid radiation of its member species over the past two million years. Male hybrids between most An. gambiae complex species pairs are sterile, and some genotype combinations in hybrid males cause inviability. We investigated the genetic basis of hybrid male inviability and sterility between An. coluzzii and An. quadriannulatus by measuring segregation distortion and performing a QTL analysis of sterility in a backcross population. Hybrid males were inviable if they inherited the An. coluzzii X chromosome and were homozygous at one or more loci in 18.9 Mb region of chromosome 3. The An. coluzzii X chromosome has a disproportionately large effect on hybrid sterility when introgressed into an An. quadriannulatus genetic background. Additionally, an epistatic interaction between the An. coluzzii X and a 1.12 Mb, pericentric region of the An. quadriannulatus 3L chromosome arm has a statistically significant contribution to the hybrid sterility phenotype. This same epistatic interaction occurs when the An. coluzzii X is introgressed into the genetic background of An. arabiensis, the sister species of An. quadriannulatus, suggesting that this may represent one of the first Dobzhansky-Muller incompatibilities to evolve early in the radiation of the Anopheles gambiae species complex. We describe the additive effects of each sterility QTL, epistatic interactions between them, and genes within QTL with protein functions related to mating behavior, reproduction, spermatogenesis, and microtubule morphogenesis, whose divergence may contribute to post-zygotic reproductive isolation between An. coluzzii and An. quadriannulatus.
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Affiliation(s)
- Kevin C Deitz
- Department of Entomology, Texas A&M University, College Station, TX, United States
| | - Willem Takken
- Laboratory of Entomology, Wageningen University and Research, Wageningen, Netherlands
| | - Michel A Slotman
- Department of Entomology, Texas A&M University, College Station, TX, United States
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10
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Montanez-Gonzalez R, Pichler V, Calzetta M, Love RR, Vallera A, Schaecher L, Caputo B, Pombi M, Petrarca V, Della Torre A, Besansky NJ. Highly specific PCR-RFLP assays for karyotyping the widespread 2Rb inversion in malaria vectors of the Anopheles gambiae complex. Parasit Vectors 2020; 13:16. [PMID: 31924251 PMCID: PMC6954590 DOI: 10.1186/s13071-019-3877-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/30/2019] [Indexed: 01/29/2023] Open
Abstract
Background Chromosomal inversion polymorphisms play a role in adaptation to heterogeneous environments. Inversion polymorphisms are implicated in the very high ecological flexibility of the three main malaria vector species of the Afrotropical Anopheles gambiae complex, facilitating the exploitation of anthropogenic environmental modifications and promoting a strong association with humans. In addition to extending the species’ spatial and temporal distribution, inversions are associated with epidemiologically relevant mosquito behavior and physiology, underscoring their medical importance. We here present novel PCR-RFLP based assays strongly predictive of genotype for the cosmopolitan 2Rb inversion in An. coluzzii and An. gambiae, a development which overcomes the numerous constraints inherent to traditional cytological karyotyping. Methods We designed PCR-RFLP genotyping assays based on tag SNPs previously computationally identified as strongly predictive (> 95%) of 2Rb genotype. We targeted those tags whose alternative allelic states destroyed or created the recognition site of a commercially available restriction enzyme, and designed assays with distinctive cleavage profiles for each inversion genotype. The assays were validated on 251 An. coluzzii and 451 An. gambiae cytologically karyotyped specimens from nine countries across Africa and one An. coluzzii laboratory colony. Results For three tag SNPs, PCR-RFLP assays (denoted DraIII, MspAI, and TatI) reliably produced robust amplicons and clearly distinguishable electrophoretic profiles for all three inversion genotypes. Results obtained with the DraIII assay are ≥ 95% concordant with cytogenetic assignments in both species, while MspAI and TatI assays produce patterns highly concordant with cytogenetic assignments only in An. coluzzii or An. gambiae, respectively. Joint application of species-appropriate pairs of assays increased the concordance levels to > 99% in An. coluzzii and 98% in An. gambiae. Potential sources of discordance (e.g. imperfect association between tag and inversion, allelic dropout, additional polymorphisms in the restriction target site, incomplete or failed restriction digestion) are discussed. Conclusions The availability of highly specific, cost effective and accessible molecular assays for genotyping 2Rb in An. gambiae and An. coluzzii allows karyotyping of both sexes and all developmental stages. These novel tools will accelerate deeper investigations into the role of this ecologically and epidemiologically important chromosomal inversion in vector biology.![]()
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Affiliation(s)
- Raquel Montanez-Gonzalez
- Eck Institute for Global Health, & Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Verena Pichler
- Dipartimento di Sanità Pubblica e Malattie Infettive, Università "La Sapienza", Istituto Pasteur-Fondazione Cenci-Bolognetti, 00185, Rome, Italy
| | - Maria Calzetta
- Dipartimento di Sanità Pubblica e Malattie Infettive, Università "La Sapienza", Istituto Pasteur-Fondazione Cenci-Bolognetti, 00185, Rome, Italy
| | - Rachel R Love
- Eck Institute for Global Health, & Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Alexandra Vallera
- Eck Institute for Global Health, & Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Lydia Schaecher
- Eck Institute for Global Health, & Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Beniamino Caputo
- Dipartimento di Sanità Pubblica e Malattie Infettive, Università "La Sapienza", Istituto Pasteur-Fondazione Cenci-Bolognetti, 00185, Rome, Italy
| | - Marco Pombi
- Dipartimento di Sanità Pubblica e Malattie Infettive, Università "La Sapienza", Istituto Pasteur-Fondazione Cenci-Bolognetti, 00185, Rome, Italy
| | - Vincenzo Petrarca
- Dipartimento di Sanità Pubblica e Malattie Infettive, Università "La Sapienza", Istituto Pasteur-Fondazione Cenci-Bolognetti, 00185, Rome, Italy
| | - Alessandra Della Torre
- Dipartimento di Sanità Pubblica e Malattie Infettive, Università "La Sapienza", Istituto Pasteur-Fondazione Cenci-Bolognetti, 00185, Rome, Italy.
| | - Nora J Besansky
- Eck Institute for Global Health, & Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.
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11
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Kahindi SC, Muriu S, Derua YA, Wang X, Zhou G, Lee MC, Mwangangi J, Atieli H, Githeko AK, Yan G. Efficacy and persistence of long-lasting microbial larvicides against malaria vectors in western Kenya highlands. Parasit Vectors 2018; 11:438. [PMID: 30064498 PMCID: PMC6069807 DOI: 10.1186/s13071-018-3009-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 07/10/2018] [Indexed: 12/02/2022] Open
Abstract
Background Chemical-based malaria vector control interventions are threatened by the development of insecticide resistance and changes in the behavior of the vectors, and thus require the development of alternative control methods. Bacterial-based larvicides have the potential to target both insecticide resistant and outdoor-biting mosquitoes and are safe to use in the environment. However, the currently available microbial larvicide formulations have a short duration of activity requiring frequent re-applications which increase the cost of control interventions. This study was designed to evaluate the efficacy and duration of activity of two long-lasting formulations of Bacillus thuringiensis var. israelensis (Bti) and Bacillus sphaericus (Bs) (LL3 and FourStar®) under field conditions in western Kenya highlands. Methods Three sites were selected for this study in the highlands of western Kenya. In each site, one hundred anopheline larval habitats were selected and assigned to one of three arms: (i) LL3; (ii) FourStar®; and (iii) untreated control larval habitats. Four types of larval habitats were surveyed: abandoned gold mines, drainage canals, fish ponds and non-fish ponds. The habitats were sampled for mosquito larvae by using a standard dipping technique and collected larvae were recorded according to the larval stages of the different Anopheles species. The larvicides were applied at manufacturers’ recommended dosage of 1 briquette per 100 square feet. Both treatment and control habitats were sampled for mosquito larvae immediately before treatment (day 0), and then at 24 hours, 3 days and weekly post-treatment for 5 months. Results Overall larval density in treatment habitats was significantly reduced after application of the two microbial larvicides as compared to the control habitats. Post-intervention reduction in anopheline larval density by LL3 was 65, 71 and 84% for 1 day, 2 weeks and 4 weeks, respectively. FourStar® reduced anopheline larval density by 60, 66 and 80% for 1 day, 2 weeks and 4 weeks, respectively. Comparisons between the treatments reveal that LL3 and FourStar® were similar in efficacy. A higher reduction in Anopheles larval density was observed in the abandoned goldmines, while drainage canals had the lowest reduction. Conclusions Both LL3 and FourStar® long-lasting microbial larvicides were effective in reducing immature stages of An. gambiae complex and An. funestus group species, with significant reductions lasting for three months post-application.
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Affiliation(s)
- Samuel C Kahindi
- School of Pure and Applied Sciences, Pwani University, Kilifi, Kenya.,Climate and Human Health Research Unit, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Simon Muriu
- School of Pure and Applied Sciences, Pwani University, Kilifi, Kenya
| | - Yahya A Derua
- Kilimanjaro Christian Medical University College, Tumaini University Makumira, Moshi, Tanzania
| | - Xiaoming Wang
- Program in Public Health, College of Health Sciences, University of California, Irvine, CA, USA
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California, Irvine, CA, USA
| | - Ming-Chieh Lee
- Program in Public Health, College of Health Sciences, University of California, Irvine, CA, USA
| | - Joseph Mwangangi
- Centre for Geographic Medicine Research-Coast, Kenya Medical Research Institute, Kilifi, Kenya
| | | | - Andrew K Githeko
- Climate and Human Health Research Unit, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California, Irvine, CA, USA.
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12
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Boussougou-Sambe ST, Eyisap WE, Tasse GCT, Mandeng SE, Mbakop LR, Enyong P, Etang J, Fokam EB, Awono-Ambene PH. Insecticide susceptibility status of Anopheles gambiae (s.l.) in South-West Cameroon four years after long-lasting insecticidal net mass distribution. Parasit Vectors 2018; 11:391. [PMID: 29973260 PMCID: PMC6033221 DOI: 10.1186/s13071-018-2979-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 06/25/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Members of the Anopheles gambiae (s.l.) complex are one of the major vectors of malaria in Africa. LLINs and IRS are the most effective tools used in vector control of malaria. However, their effectiveness may be hampered by the development and spread of insecticide resistance in the target vectors species. The objective of this study was to assess the susceptibility of Anopheles gambiae (s.l.) mosquitoes from South-West Cameroon to deltamethrin, permethrin and to malathion, four years after the mass deployment of LLINs. METHODS Anopheles larvae were collected from Limbe, Tiko and Buea, three cities of the Fako division and reared until adult emergence. Adult mosquitoes from field larvae were identified as belonging to the Anopheles gambiae (s.l.) complex using standard identification keys. Susceptibility of mosquito samples to deltamethrin, permethrin and malathion was assessed using WHO susceptibility tests protocol for adult mosquitoes. Molecular identification of tested samples was performed using the PCR SINE200 protocol and by PCR-RFLP. The kdr alleles were genotyped using the hot ligation oligonucleotide assay (HOLA). RESULTS Two species of the An. gambiae (s.l.) complex, An. coluzzii and An. gambiae (s.s.) were identified in all three study locations with high proportions of An. coluzzii in Limbe (84.06%) and Tiko (92.2%), while in Buea, An. coluzzii (55.6%) and An. gambiae (s.s.) (44.4%) occurred almost in the same proportions. Tested samples were found resistant to pyrethroids (deltamethrin and permethrin) in all locations (< 90% mortality), with > 3-fold increase of KDT50 values compared with the Kisumu susceptible reference strain of An. gambiae (s.s.). However, the mosquito populations from Limbe and Buea were fully susceptible to malathion. The L1014F kdr was found in both An. coluzzii and An. gambiae (s.s.) with the highest frequencies found in An. gambiae (s.l.) populations from Tiko (94%) and Buea (90%) compared with the Limbe population (66%) (P = 0.00063, df = 2). No kdr L1014S was observed in analyzed samples. CONCLUSIONS These findings reemphasize the ongoing development of An. gambiae (s.l.) resistance to pyrethroids used in impregnating LLINs and suggest the use of malathion as an alternative insecticide for IRS in complementarity with LLINs.
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Affiliation(s)
- Stravensky Térence Boussougou-Sambe
- Microbiology and Parasitology Department, University of Buea, P.O. Box 63, Buea, Cameroon.,Institut de Recherche de Yaoundé, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroon.,Centre de Recherches Médicales de Lambaréné (CERMEL), P.O Box 242, Lambaréné, Gabon.,Institute of Tropical Medicine, University of Tübingen, Wilhemstrasse 27, P.O. Box 72074, Tübingen, Germany
| | - Wolfgang Ekoko Eyisap
- Institut de Recherche de Yaoundé, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroon.,Laboratory of Animal Biology and Physiology, University of Douala, PO Box 24157, Douala, Cameroon
| | - Geraud Canis Taboue Tasse
- Laboratory for Biodiversity and Conservation Biology, University of Buea, P.O. Box 63, Buea, Cameroon.,Department of Zoology and Animal Physiology, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Stanislas Elysee Mandeng
- Institut de Recherche de Yaoundé, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroon.,Department of Biology and Animal Physiology, University of Yaoundé I, P.O. Box 3851, Messa, Yaoundé, Cameroon
| | - Lili Ranaise Mbakop
- Institut de Recherche de Yaoundé, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroon.,Department of Biology and Animal Physiology, University of Yaoundé I, P.O. Box 3851, Messa, Yaoundé, Cameroon
| | - Peter Enyong
- Microbiology and Parasitology Department, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Josiane Etang
- Institut de Recherche de Yaoundé, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroon.,Faculty of Medicine and Pharmaceutical Sciences, University of Douala, P.O. Box 2701, Douala, Cameroon
| | - Eric Bertrand Fokam
- Laboratory for Biodiversity and Conservation Biology, University of Buea, P.O. Box 63, Buea, Cameroon.,Department of Zoology and Animal Physiology, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Parfait H Awono-Ambene
- Institut de Recherche de Yaoundé, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroon.
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13
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Mbokazi F, Coetzee M, Brooke B, Govere J, Reid A, Owiti P, Kosgei R, Zhou S, Magagula R, Kok G, Namboze J, Tweya H, Mabuza A. Changing distribution and abundance of the malaria vector Anopheles merus in Mpumalanga Province, South Africa. Public Health Action 2018; 8:S39-S43. [PMID: 29713593 DOI: 10.5588/pha.17.0034] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [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: 05/29/2017] [Accepted: 12/10/2017] [Indexed: 11/10/2022] Open
Abstract
Background: The malaria vector Anopheles merus occurs in the Mpumalanga Province of South Africa. As its contribution to malaria transmission in South Africa has yet to be ascertained, an intensification of surveillance is necessary to provide baseline information on this species. The aim of this study was therefore to map An. merus breeding sites in the Ehlanzeni District of Mpumalanga Province and to assess qualitative trends in the distribution and relative abundance of this species over a 9-year period. Methods: The study was carried out during the period 2005-2014 in the four high-risk municipalities of Ehlanzeni District. Fifty-two breeding sites were chosen from all water bodies that produced anopheline mosquitoes. The study data were extracted from historical entomological records that are captured monthly. Results: Of the 15 058 Anopheles mosquitoes collected, 64% were An. merus. The abundance and distribution of An. merus increased throughout the four municipalities in Ehlanzeni District during the study period. Conclusion: The expanded distribution and increased abundance of An. merus in the Ehlanzeni District may contribute significantly to locally acquired malaria in Mpumalanga Province, likely necessitating the incorporation of additional vector control methods specifically directed against populations of this species.
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Affiliation(s)
- F Mbokazi
- Malaria Elimination Programme, Mpumalanga Department of Health, Ehlanzeni District, Mpumalanga, South Africa
| | - M Coetzee
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Vector Control Reference Laboratory, Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - B Brooke
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Vector Control Reference Laboratory, Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - J Govere
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - A Reid
- Operational Research Unit, Operational Centre Brussels, Medécins Sans Frontières, Luxembourg
| | - P Owiti
- Academic Model Providing Access to Healthcare (AMPATH), Eldoret, Kenya
| | - R Kosgei
- Department of Obstetrics and Gynaecology, University of Nairobi, Nairobi, Kenya
| | - S Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China
| | - R Magagula
- Malaria Elimination Programme, Mpumalanga Department of Health, Ehlanzeni District, Mpumalanga, South Africa
| | - G Kok
- Malaria Elimination Programme, Mpumalanga Department of Health, Ehlanzeni District, Mpumalanga, South Africa
| | - J Namboze
- World Health Organization, Regional Office for Africa Region, Asmara, Eritrea
| | - H Tweya
- The Lighthouse Trust, Lilongwe, Malawi
| | - A Mabuza
- Malaria Elimination Programme, Mpumalanga Department of Health, Ehlanzeni District, Mpumalanga, South Africa
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14
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Muller GC, Junnila A, Traore MM, Traore SF, Doumbia S, Sissoko F, Dembele SM, Schlein Y, Arheart KL, Revay EE, Kravchenko VD, Witt A, Beier JC. The invasive shrub Prosopis juliflora enhances the malaria parasite transmission capacity of Anopheles mosquitoes: a habitat manipulation experiment. Malar J 2017; 16:237. [PMID: 28676093 PMCID: PMC5497341 DOI: 10.1186/s12936-017-1878-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 05/26/2017] [Indexed: 11/10/2022] Open
Abstract
Background A neglected aspect of alien invasive plant species is their influence on mosquito vector ecology and malaria transmission. Invasive plants that are highly attractive to Anopheles mosquitoes provide them with sugar that is critical to their survival. The effect on Anopheles mosquito populations was examined through a habitat manipulation experiment that removed the flowering branches of highly attractive Prosopis juliflora from selected villages in Mali, West Africa. Methods Nine villages in the Bandiagara district of Mali were selected, six with flowering Prosopis juliflora, and three without. CDC-UV light traps were used to monitor their Anopheles spp. vector populations, and recorded their species composition, population size, age structure, and sugar feeding status. After 8 days, all of the flowering branches were removed from three villages and trap catches were analysed again. Results Villages where flowering branches of the invasive shrub Prosopis juliflora were removed experienced a threefold drop in the older more dangerous Anopheles females. Population density dropped by 69.4% and the species composition shifted from being a mix of three species of the Anopheles gambiae complex to one dominated by Anopheles coluzzii. The proportion of sugar fed females dropped from 73 to 15% and males from 77 to 10%. Conclusions This study demonstrates how an invasive plant shrub promotes the malaria parasite transmission capacity of African malaria vector mosquitoes. Proper management of invasive plants could potentially reduce mosquito populations and malaria transmission.
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Affiliation(s)
- Gunter C Muller
- Department of Microbiology and Molecular Genetics, IMRIC, Kuvin Centre for the Study of Infectious and Tropical Diseases, Faculty of Medicine, Hebrew University, Jerusalem, Israel. .,Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odonto-Stomatology, University of Bamako, Bamako, BP 1805, Mali.
| | - Amy Junnila
- Department of Microbiology and Molecular Genetics, IMRIC, Kuvin Centre for the Study of Infectious and Tropical Diseases, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Mohamad M Traore
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odonto-Stomatology, University of Bamako, Bamako, BP 1805, Mali
| | - Sekou F Traore
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odonto-Stomatology, University of Bamako, Bamako, BP 1805, Mali
| | - Seydou Doumbia
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odonto-Stomatology, University of Bamako, Bamako, BP 1805, Mali
| | - Fatoumata Sissoko
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odonto-Stomatology, University of Bamako, Bamako, BP 1805, Mali
| | - Seydou M Dembele
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odonto-Stomatology, University of Bamako, Bamako, BP 1805, Mali
| | - Yosef Schlein
- Department of Microbiology and Molecular Genetics, IMRIC, Kuvin Centre for the Study of Infectious and Tropical Diseases, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Kristopher L Arheart
- Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Edita E Revay
- Department of Anatomy and Cell Biology, Bruce Rappaport Faculty of Medicine, Technion, 34995, Haifa, Israel
| | | | - Arne Witt
- CABI Africa, Box 633-00621, Nairobi, Kenya
| | - John C Beier
- Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, FL, USA
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15
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Coulibaly YI, Coulibaly SY, Dolo H, Konate S, Diallo AA, Doumbia SS, Soumaoro L, Coulibaly ME, Dicko I, Sangare MB, Dembele B, Sangare M, Dembele M, Touré YT, Kelly-Hope L, Polman K, Kyelem D, Traore SF, Bockarie M, Klion AD, Nutman TB. Dynamics of antigenemia and transmission intensity of Wuchereria bancrofti following cessation of mass drug administration in a formerly highly endemic region of Mali. Parasit Vectors 2016; 9:628. [PMID: 27912789 PMCID: PMC5135747 DOI: 10.1186/s13071-016-1911-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 11/24/2016] [Indexed: 11/16/2022] Open
Abstract
Background After seven annual rounds of mass drug administration (MDA) in six Malian villages highly endemic for Wuchereria bancrofti (overall prevalence rate of 42.7%), treatment was discontinued in 2008. Surveillance was performed over the ensuing 5 years to detect recrudescence. Methods Circulating filarial antigen (CFA) was measured using immunochromatographic card tests (ICT) and Og4C3 ELISA in 6–7 year-olds. Antibody to the W. bancrofti infective larval stage (L3) antigen, Wb123, was tested in the same population in 2012. Microfilaraemia was assessed in ICT-positive subjects. Anopheles gambiae complex specimens were collected monthly using human landing catch (HLC) and pyrethrum spray catch (PSC). Anopheles gambiae complex infection with W. bancrofti was determined by dissection and reverse transcriptase polymerase chain reaction (RT-PCR) of mosquito pools. Results Annual CFA prevalence rates using ICT in children increased over time from 0% (0/289) in 2009 to 2.7% (8/301) in 2011, 3.9% (11/285) in 2012 and 4.5% (14/309) in 2013 (trend χ2
= 11.85, df =3, P = 0.0006). Wb123 antibody positivity rates in 2013 were similar to the CFA prevalence by ELISA (5/285). Although two W. bancrofti-infected Anopheles were observed by dissection among 12,951 mosquitoes collected by HLC, none had L3 larvae when tested by L3-specific RT-PCR. No positive pools were detected among the mosquitoes collected by pyrethrum spray catch. Whereas ICT in 6–7 year-olds was the major surveillance tool, ICT positivity was also assessed in older children and adults (8–65 years old). CFA prevalence decreased in this group from 4.9% (39/800) to 3.5% (28/795) and 2.8% (50/1,812) in 2009, 2011 and 2012, respectively (trend χ2
= 7.361, df =2, P = 0.0067). Some ICT-positive individuals were microfilaraemic in 2009 [2.6% (1/39)] and 2011 [8.3% (3/36)], but none were positive in 2012 or 2013. Conclusion Although ICT rates in children increased over the 5-year surveillance period, the decrease in ICT prevalence in the older group suggests a reduction in transmission intensity. This was consistent with the failure to detect infective mosquitoes or microfilaraemia. The threshold of ICT positivity in children may need to be re-assessed and other adjunct surveillance tools considered.
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Affiliation(s)
- Yaya I Coulibaly
- Filariasis Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali. .,Filarial Program Support Unit, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Siaka Y Coulibaly
- Filariasis Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Housseini Dolo
- Filariasis Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Siaka Konate
- Filariasis Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Abdallah A Diallo
- Filariasis Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Salif S Doumbia
- Filariasis Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Lamine Soumaoro
- Filariasis Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Michel E Coulibaly
- Filariasis Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Ilo Dicko
- Filariasis Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Moussa B Sangare
- Filariasis Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Benoit Dembele
- Filariasis Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Modibo Sangare
- Filariasis Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | | | - Yeya T Touré
- Faculty of Medicine and Odontostomatology of Bamako, Bamako, Mali
| | - Louise Kelly-Hope
- Filarial Program Support Unit, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Katja Polman
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Dominique Kyelem
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Decatur, GA, USA
| | - Sekou F Traore
- Filariasis Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Point G, Bamako, Mali
| | - Moses Bockarie
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Amy D Klion
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Thomas B Nutman
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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16
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Wragge SE, Toure D, Coetzee M, Gilbert A, Christian R, Segoea G, Hunt RH, Coetzee M. Malaria control at a gold mine in Sadiola District, Mali, and impact on transmission over 10 years. Trans R Soc Trop Med Hyg 2016; 109:755-62. [PMID: 26626339 DOI: 10.1093/trstmh/trv089] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The SEMOS gold mine's malaria vector control programme forms part of the company's community responsibilities with the programme being managed by the mine's health department since 2005. METHODS Data from approximately 10 years of malaria vector control for the Sadiola District are given: namely malaria vector control methods used by the control programme, positive malaria case data and entomological surveys from 2006, 2011 and 2014. RESULTS Distribution of pyrethroid-treated bed nets and indoor residual spraying (IRS) with deltamethrin were implemented by the programme from 2005-2011. No IRS was done in 2012. Spraying with the organophosphate, pirimiphos-methyl resumed in 2013 and 2014 and was followed by a 70% drop in malaria cases in 2014. Anopheles arabiensis was the major vector present in 2006 and was susceptible to deltamethrin. In 2011 and 2014, An. gambiae s.s. was the most abundant vector with deltamethrin 24 h mortality of 68% and 19%, respectively. CONCLUSIONS Resistance to the pyrethroid deltamethrin has increased in An. gambiae s.s. since 2011, possibly due to the scale-up in distribution of long-lasting insecticide-treated bed nets. Resistance management strategies are recommended using different classes of insecticides for IRS, and including the distribution of new-generation bed nets.
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Affiliation(s)
- Sue-Ellen Wragge
- SEMOS Gold Mine, Health Department, Sadiola, Hamdallaye ACI 2000 pres' des Assurance LAFIA, B.P.E-1194, Bamako, Mali
| | - Dramane Toure
- SEMOS Gold Mine, Health Department, Sadiola, Hamdallaye ACI 2000 pres' des Assurance LAFIA, B.P.E-1194, Bamako, Mali
| | - Marelize Coetzee
- SEMOS Gold Mine, Health Department, Sadiola, Hamdallaye ACI 2000 pres' des Assurance LAFIA, B.P.E-1194, Bamako, Mali
| | - Allison Gilbert
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, 7 York Avenue, Johannesburg 2001, South Africa Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, Private Bag X4, Sandringham 2131, South Africa
| | - Riann Christian
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, 7 York Avenue, Johannesburg 2001, South Africa Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, Private Bag X4, Sandringham 2131, South Africa
| | - Godira Segoea
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, 7 York Avenue, Johannesburg 2001, South Africa Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, Private Bag X4, Sandringham 2131, South Africa
| | - Richard H Hunt
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, 7 York Avenue, Johannesburg 2001, South Africa Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, Private Bag X4, Sandringham 2131, South Africa
| | - Maureen Coetzee
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, 7 York Avenue, Johannesburg 2001, South Africa Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, Private Bag X4, Sandringham 2131, South Africa
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17
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Low M, Tsegaye AT, Ignell R, Hill S, Elleby R, Feltelius V, Hopkins R. The importance of accounting for larval detectability in mosquito habitat-association studies. Malar J 2016; 15:253. [PMID: 27142303 PMCID: PMC4855760 DOI: 10.1186/s12936-016-1308-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 04/23/2016] [Indexed: 11/10/2022] Open
Abstract
Background Mosquito habitat-association studies are an important basis for disease control programmes and/or vector distribution models. However, studies do not explicitly account for incomplete detection during larval presence and abundance surveys, with potential for significant biases because of environmental influences on larval behaviour and sampling efficiency. Methods Data were used from a dip-sampling study for Anopheles larvae in Ethiopia to evaluate the effect of six factors previously associated with larval sampling (riparian vegetation, direct sunshine, algae, water depth, pH and temperature) on larval presence and detectability. Comparisons were made between: (i) a presence-absence logistic regression where samples were pooled at the site level and detectability ignored, (ii) a success versus trials binomial model, and (iii) a presence-detection mixture model that separately estimated presence and detection, and fitted different explanatory variables to these estimations. Results Riparian vegetation was consistently highlighted as important, strongly suggesting it explains larval presence (−). However, depending on how larval detectability was estimated, the other factors showed large variations in their statistical importance. The presence-detection mixture model provided strong evidence that larval detectability was influenced by sunshine and water temperature (+), with weaker evidence for algae (+) and water depth (−). For larval presence, there was also some evidence that water depth (−) and pH (+) influenced site occupation. The number of dip-samples needed to determine if larvae were likely present at a site was condition dependent: with sunshine and warm water requiring only two dips, while cooler water and cloud cover required 11. Conclusions Environmental factors influence true larval presence and larval detectability differentially when sampling in field conditions. Researchers need to be more aware of the limitations and possible biases in different analytical approaches used to associate larval presence or abundance with local environmental conditions. These effects can be disentangled using data that are routinely collected (i.e., multiple dip samples at each site) by employing a modelling approach that separates presence from detectability. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1308-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Matthew Low
- Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, 75007, Uppsala, Sweden.
| | - Admasu Tassew Tsegaye
- Ethiopian Institute of Water Resources, Addis Ababa University, Addis Ababa, Ethiopia
| | - Rickard Ignell
- Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102, 23053, Alnarp, Sweden
| | - Sharon Hill
- Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102, 23053, Alnarp, Sweden
| | - Rasmus Elleby
- Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, 75007, Uppsala, Sweden.,Department of Earth Sciences, Uppsala University, Uppsala, Sweden
| | - Vilhelm Feltelius
- Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, 75007, Uppsala, Sweden.,Department of Earth Sciences, Uppsala University, Uppsala, Sweden
| | - Richard Hopkins
- Natural Resources Institute, University of Greenwich, London, UK
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18
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Fabrigar DJ, Hubbart C, Miles A, Rockett K. High-throughput genotyping of Anopheles mosquitoes using intact legs by Agena Biosciences iPLEX. Mol Ecol Resour 2015; 16:480-6. [PMID: 26426152 DOI: 10.1111/1755-0998.12473] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [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: 05/27/2015] [Revised: 09/16/2015] [Accepted: 09/25/2015] [Indexed: 11/28/2022]
Abstract
Recent developments in genotyping technologies coupled with the growing desire to characterize genome variation in Anopheles populations open the opportunity to develop more effective genotyping strategies for high-throughput screening. A major bottleneck of this goal is nucleic acid extraction. Here, we examined the feasibility of using intact portions of a mosquito's leg as sources of template DNA for whole-genome amplification (WGA) by primer-extension preamplification. We used the Agena Biosciences MassARRAY(®) platform (formerly Sequenom) to genotype 78 SNPs for 265 WGA leg samples. We performed nucleic acid extraction on 36 mosquito carcasses and compared the genotype call concordance with their corresponding legs and observed full concordance. Using three legs instead of one improved genotyping success rates (96% vs. 89%, respectively), although this difference was not significant. We provide a proof of concept that WGA reactions can be performed directly on mosquito legs, thereby eliminating the need to extract nucleic acid. This approach is straightforward and sensitive and allows both species determination and genotyping of Anopheles mosquitoes to be performed in a high-throughput manner. Our protocol also leaves the mosquito body intact facilitating other experimental analysis to be undertaken on the same sample. Based on our findings, this method would also be suitable for use with other insect species.
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Affiliation(s)
- Danica Joy Fabrigar
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| | - Christina Hubbart
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Headington, Oxford, OX3 7BN, UK
| | - Alistair Miles
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Headington, Oxford, OX3 7BN, UK
| | - Kirk Rockett
- Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Headington, Oxford, OX3 7BN, UK
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19
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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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