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Lamy K, Tran A, Portafaix T, Leroux MD, Baldet T. Impact of regional climate change on the mosquito vector Aedes albopictus in a tropical island environment: La Réunion. Sci Total Environ 2023; 875:162484. [PMID: 36889019 DOI: 10.1016/j.scitotenv.2023.162484] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [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: 10/24/2022] [Revised: 02/22/2023] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
The recent expansion of Aedes albopictus across continents in both tropical and temperate regions and the exponential growth of dengue cases over the past 50 years represent a significant risk to human health. Although climate change is not the only factor responsible for the increase and spread of dengue cases worldwide, it might increase the risk of disease transmission at global and regional scale. Here we show that regional and local variations in climate can induce differential impacts on the abundance of Ae. albopictus. We use the instructive example of Réunion Island with its varied climatic and environmental conditions and benefiting from the availability of meteorological, climatic, entomological and epidemiological data. Temperature and precipitation data based on regional climate model simulations (3 km × 3 km) are used as inputs to a mosquito population model for three different climate emission scenarios. Our objective is to study the impact of climate change on the life cycle dynamics of Ae. albopictus in the 2070-2100 time horizon. Our results show the joint influence of temperature and precipitation on Ae. albopictus abundance as a function of elevation and geographical subregion. At low-elevations areas, decreasing precipitation is expected to have a negative impact on environmental carrying capacity and, consequently, on Ae. albopictus abundance. At mid- and high-elevations, decreasing precipitation is expected to be counterbalanced by a significant warming, leading to faster development rates at all life stages, and consequently increasing the abundance of this important dengue vector in 2070-2100.
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Affiliation(s)
- K Lamy
- LACy, Laboratoire de l'Atmosphère et des Cyclones (UMR 8105 CNRS, Université de La Réunion, Météo-France), Saint-Denis de La Réunion, France.
| | - A Tran
- CIRAD, UMR TETIS, Sainte-Clotilde, La Réunion, France
| | - T Portafaix
- LACy, Laboratoire de l'Atmosphère et des Cyclones (UMR 8105 CNRS, Université de La Réunion, Météo-France), Saint-Denis de La Réunion, France
| | - M D Leroux
- Météo-France, Direction Interrégionale pour l'Océan Indien, Saint-Denis de La Réunion, France
| | - T Baldet
- ASTRE, Univ. Montpellier, Cirad, INRA, Sainte-Clotilde, La Réunion, France
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Bakhoum M, Fall A, Seck M, Fall M, Ciss M, Garros C, Bouyer J, Gimonneau G, Baldet T. Physicochemical factors affecting the diversity and abundance of Afrotropical Culicoides species in larval habitats in Senegal. Acta Trop 2021; 220:105932. [PMID: 33933445 DOI: 10.1016/j.actatropica.2021.105932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/14/2021] [Accepted: 04/16/2021] [Indexed: 11/26/2022]
Abstract
Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are the biological vectors of arboviruses of global importance in animal health. We characterized the physicochemical parameters that determine the density and composition of the main Culicoides species of veterinary interest in larval habitats of the Niayes region of Senegal. For this purpose, we combined larval and substrate sampling in the field in different habitat types with adult emergence and physicochemical analyses in the laboratory. Three major habitat types were identified, conditioning the predominant species of Culicoides and pH and the amount of organic matter were positively correlated with the abundance of larvae and emerging Culicoides, as opposed to salinity. The diversity of emerging Culicoides was positively correlated with pH while it was negatively correlated with salinity. Culicoides distinctipennis was the predominant species in the larval habitat group of freshwater lake edges. In the larval habitat group of pond and puddle edges, C. oxystoma and C. nivosus were predominant; both species were again most abundant in the larval habitat group of saltwater lake edges. These variabilities in physicochemical parameters support the distribution of different Culicoides species in different habitat groups. These results make it possible to implement effective, selective and environmental-friendly control measures but also to improve current models for estimating the abundance of adult vector populations at a local scale.
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Laroche L, Ravel S, Baldet T, Lancelot R, Chandre F, Rossignol M, Le Goff V, Duhayon M, Fafet JF, Parker AG, Bouyer J. Boosting the sterile insect technique with pyriproxyfen increases tsetse flies Glossina palpalis gambiensis sterilization in controlled conditions. Sci Rep 2020; 10:9947. [PMID: 32561776 PMCID: PMC7305199 DOI: 10.1038/s41598-020-66850-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 05/26/2020] [Indexed: 01/16/2023] Open
Abstract
Tsetse flies (Diptera: Glossinidae) are the main vectors of animal and human trypanosomoses in Africa. The Sterile Insect Technique (SIT) has proven effective in controlling tsetse flies when applied to isolated populations but necessitates the production of large numbers of sterile males. A new approach, called boosted SIT, combining SIT with the contamination of wild females by sterile males coated with biocides has been proposed for large-scale control of vector populations. The aim of the study was to evaluate this new approach using pyriproxyfen on the riverine species Glossina palpalis gambiensis (Vanderplank, 1949) in the laboratory. The contamination dose and persistence of pyriproxyfen on sterile males, the impact of pyriproxyfen on male survival, and the dynamics of pyriproxyfen transfer from a sterile male to a female during mating, as well as the impact of pyriproxyfen on pupal production and adult emergence, were evaluated in the laboratory. For this purpose, a method of treatment by impregnating sterile males with a powder containing 40% pyriproxyfen has been developed. The results showed that the pyriproxyfen has no impact on the survival of sterile males. Pyriproxyfen persisted on sterile males for up to 10 days at a dose of 100 ng per fly. In addition, the horizontal transfer of pyriproxyfen from a treated sterile male to a female during mating could be measured with an average of 50 ng of pyriproxyfen transferred. After contacts without mating, the average quantity transferred was more than 10 ng. Finally, the pyriproxyfen powder was very effective on G. p. gambiensis leading to 0% emergence of the pupae produced by contaminated females. These promising results must be confirmed in the field. A large-scale assessment of this boosted pyriproxyfen-based SIT approach will be carried out against tsetse flies in Senegal (West Africa).
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Affiliation(s)
- L Laroche
- Intertryp, IRD, Cirad, Univ Montpellier, Montpellier, France. .,MIVEGEC, IRD, CNRS, Univ Montpellier, Montpellier, France.
| | - S Ravel
- Intertryp, IRD, Cirad, Univ Montpellier, Montpellier, France
| | - T Baldet
- ASTRE, Cirad, INRA, Univ Montpellier, Montpellier, France
| | - R Lancelot
- ASTRE, Cirad, INRA, Univ Montpellier, Montpellier, France
| | - F Chandre
- MIVEGEC, IRD, CNRS, Univ Montpellier, Montpellier, France
| | - M Rossignol
- MIVEGEC, IRD, CNRS, Univ Montpellier, Montpellier, France
| | - V Le Goff
- MIVEGEC, IRD, CNRS, Univ Montpellier, Montpellier, France
| | - M Duhayon
- ASTRE, Cirad, INRA, Univ Montpellier, Montpellier, France
| | | | - A G Parker
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, IAEA, Vienna, Austria.,Roppersbergweg 15, 2381, Laab im Walde, Austria
| | - J Bouyer
- Intertryp, IRD, Cirad, Univ Montpellier, Montpellier, France.,ASTRE, Cirad, INRA, Univ Montpellier, Montpellier, France.,Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, IAEA, Vienna, Austria
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Bakhoum M, Fall M, Seck M, Gardès L, Fall A, Diop M, Mall I, Balenghien T, Baldet T, Gimonneau G, Garros C, Bouyer J. Foraging range of arthropods with veterinary interest: New insights for Afrotropical Culicoides biting midges (Diptera: Ceratopogonidae) using the ring method. Acta Trop 2016; 157:59-67. [PMID: 26826391 DOI: 10.1016/j.actatropica.2016.01.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 01/14/2016] [Accepted: 01/24/2016] [Indexed: 10/22/2022]
Abstract
The identification of blood meal source of arthropod vector species contributes to the understanding of host-vector-pathogen interactions. The aim of the current work was to identify blood meal source in Culicoides biting midge species, biological vectors of internationally important arboviruses of livestock and equids, using a new ecological approach. We examined the correlation between blood meal source identified in engorged Culicoides females collected in a suction light trap and the available vertebrate hosts along four rings (200, 500, 1000 and 2000 m) centered at the trap site and described the foraging range of the three main vector species of veterinary interest present in the study area, Culicoides imicola, Culicoides kingi and Culicoides oxystoma. The study was performed in four sites localized in the Niayes region of Senegal (West Africa) where recent outbreaks of African horse sickness occurred. Blood meal source identification was carried out by species-specific multiplex PCRs with genomic DNA extracted from the abdomen of engorged females collected during nine night collections for twenty-six collections. The four most abundant hosts present in the studied area (horse, cattle, goat and sheep) were surveyed in each ring zone. The blood meal source varied according to Culicoides species and host availability in each site. C. oxystoma and C. imicola females mainly fed on horses readily available at 200 m maximum from the trap location whereas females of C. kingi fed mainly on cattle, at variable distances from the traps (200 to 2000 m). C. oxystoma may also feed on other vertebrates. We discuss the results in relation with the transmission of Culicoides-borne arboviruses and the species dispersion capacities.
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Jacquet S, Garros C, Lombaert E, Walton C, Restrepo J, Allene X, Baldet T, Cetre-Sossah C, Chaskopoulou A, Delecolle JC, Desvars A, Djerbal M, Fall M, Gardes L, de Garine-Wichatitsky M, Goffredo M, Gottlieb Y, Gueye Fall A, Kasina M, Labuschagne K, Lhor Y, Lucientes J, Martin T, Mathieu B, Miranda M, Pages N, Pereira da Fonseca I, Ramilo DW, Segard A, Setier-Rio ML, Stachurski F, Tabbabi A, Talla Seck M, Venter G, Zimba M, Balenghien T, Guis H, Chevillon C, Bouyer J, Huber K. Colonization of the Mediterranean basin by the vector biting midge speciesCulicoides imicola: an old story. Mol Ecol 2015; 24:5707-25. [DOI: 10.1111/mec.13422] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 10/06/2015] [Accepted: 10/09/2015] [Indexed: 11/27/2022]
Affiliation(s)
- S. Jacquet
- CIRAD UMR15 CMAEE; 34398 Montpellier France
- INRA UMR1309 CMAEE; 34398 Montpellier France
- CNRS; UMR 5290 Maladies Infectieuses & Vecteurs-Ecologie, Génétique, Ecologie, Contrôle (MIVEGEC); Université de Montpellier; Montpellier France
- IRD; UR 224 MIVEGEC; BP 64501, Agropolis 34394 Montpellier Cedex 5 France
| | - C. Garros
- CIRAD UMR15 CMAEE; 34398 Montpellier France
- INRA UMR1309 CMAEE; 34398 Montpellier France
| | - E. Lombaert
- INRA; UMR1355; Institut Sophia Agrobiotech; 06903 Sophia Antipolis France
| | - C. Walton
- Computational and Evolutionary Biology; Faculty of Life Sciences; University of Manchester; Manchester UK
| | - J. Restrepo
- CIRAD UMR15 CMAEE; 34398 Montpellier France
- INRA UMR1309 CMAEE; 34398 Montpellier France
| | - X. Allene
- CIRAD UMR15 CMAEE; 34398 Montpellier France
- INRA UMR1309 CMAEE; 34398 Montpellier France
| | - T. Baldet
- CIRAD UMR15 CMAEE; 34398 Montpellier France
- INRA UMR1309 CMAEE; 34398 Montpellier France
| | - C. Cetre-Sossah
- CIRAD UMR15 CMAEE; 34398 Montpellier France
- INRA UMR1309 CMAEE; 34398 Montpellier France
- Plateforme de recherche CYROI; CRVOI; Sainte Clotilde La Réunion France
| | - A. Chaskopoulou
- USDA-ARS European Biological Control Laboratory; 54623 Thessaloniki Greece
| | - J.-C. Delecolle
- Medicine Faculty; Institute of Parasitology and Tropical Pathology (IPPTS); EA7292 67000 Strasbourg France
| | - A. Desvars
- Department of Clinical Microbiology; Umea University; Umea Sweden
| | - M. Djerbal
- Regional Veterinary Laboratory of Draa-Ben-Kheda; Tizi-Ouzou Algeria
| | - M. Fall
- ISRA-LNERV; BP 2057 Dakar Senegal
| | - L. Gardes
- CIRAD UMR15 CMAEE; 34398 Montpellier France
- INRA UMR1309 CMAEE; 34398 Montpellier France
| | - M. de Garine-Wichatitsky
- Cirad; UPR AGIRs, RP-PCP; Harare Zimbabwe
- Cirad; UPR AGIRs; Montpellier France
- Department of Biological Sciences, Entomology; University of Zimbabwe; PO Box MP 167 Mount Pleasant Harare Zimbabwe
| | - M. Goffredo
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise ‘G. Caporale’; 64100 Teramo Italy
| | - Y. Gottlieb
- Koret School of Veterinary Medicine; The Robert H. Smith Faculty of Agriculture, Food and Environment; The Hebrew University of Jerusalem; Rehovot Israel
| | | | - M. Kasina
- Kenya Agricultural and Livestock Research Organization Sericulture; PO Box 7816 Code 01000 Thika Kenya
| | - K. Labuschagne
- Agricultural Research Council-Onderstepoort Veterinary Institute, Parasites, Vectors and Vector-borne Diseases; Onderstepoort 0110 South Africa
| | - Y. Lhor
- Office National de Sécurité Sanitaire des produits Alimentaires (ONSSA); Rabat Morocco
| | - J. Lucientes
- Departamento de Patología Animal; Facultad de Veterinaria; Universidad de Zaragoza; Zaragoza Spain
| | - T. Martin
- UR Hortsys; Cirad; Montpellier France
- Plant Health Department; ICIPE; Nairobi Kenya
| | - B. Mathieu
- Medicine Faculty; Institute of Parasitology and Tropical Pathology (IPPTS); EA7292 67000 Strasbourg France
- EID Méditerranée; 34184 Montpellier France
| | - M. Miranda
- Laboratory of Zoology; University of Balearics (UIB); Palma de Mallorca Spain
| | - N. Pages
- INRA UMR1309 CMAEE; 34398 Montpellier France
- Centre de Recerca en Sanitat Animal (CReSA); UAB-IRTA; Campus de la Universitat Autònoma de Barcelona 08193 Bellaterra (Cerdanyola del Vallès) Spain
- CIRAD; UMR CMAEE; 97170 Petit Bourg Guadeloupe France
| | | | - D. W. Ramilo
- Faculdade de Medicina Veterinária; CIISA; ULisboa; 1300-477 Lisboa Portugal
| | - A. Segard
- CNRS; UMR 5175 CEFE; Université de Montpellier; Montpellier France
- EPHE Campus CNRS; 1919 route de Mende 34293 Montpellier Cedex 5 France
| | | | - F. Stachurski
- CIRAD UMR15 CMAEE; 34398 Montpellier France
- INRA UMR1309 CMAEE; 34398 Montpellier France
| | - A. Tabbabi
- Lab of Medical Parasitology, Biotechnologies & Biomolecules (LR 11 IPT 06); Pasteur Institute of Tunis; Tunis Tunisia
| | | | - G. Venter
- Agricultural Research Council-Onderstepoort Veterinary Institute, Parasites, Vectors and Vector-borne Diseases; Onderstepoort 0110 South Africa
| | - M. Zimba
- Department of Biological Sciences, Entomology; University of Zimbabwe; PO Box MP 167 Mount Pleasant Harare Zimbabwe
| | - T. Balenghien
- CIRAD UMR15 CMAEE; 34398 Montpellier France
- INRA UMR1309 CMAEE; 34398 Montpellier France
| | - H. Guis
- CIRAD UMR15 CMAEE; 34398 Montpellier France
- INRA UMR1309 CMAEE; 34398 Montpellier France
| | - C. Chevillon
- CNRS; UMR 5290 Maladies Infectieuses & Vecteurs-Ecologie, Génétique, Ecologie, Contrôle (MIVEGEC); Université de Montpellier; Montpellier France
- IRD; UR 224 MIVEGEC; BP 64501, Agropolis 34394 Montpellier Cedex 5 France
| | - J. Bouyer
- CIRAD UMR15 CMAEE; 34398 Montpellier France
- INRA UMR1309 CMAEE; 34398 Montpellier France
- ISRA-LNERV; BP 2057 Dakar Senegal
| | - K. Huber
- CIRAD UMR15 CMAEE; 34398 Montpellier France
- INRA UMR1309 CMAEE; 34398 Montpellier France
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Desvars A, Grimaud Y, Guis H, Esnault O, Allène X, Gardès L, Balenghien T, Baldet T, Delécolle J, Garros C. First overview of the Culicoides Latreille (Diptera: Ceratopogonidae) livestock associated species of Reunion Island, Indian Ocean. Acta Trop 2015; 142:5-19. [PMID: 25447828 DOI: 10.1016/j.actatropica.2014.10.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 10/20/2014] [Accepted: 10/26/2014] [Indexed: 10/24/2022]
Abstract
This study establishes the first faunistic inventory of livestock associated Culicoides (Diptera: Ceratopogonidae) species of Reunion Island (Indian Ocean), where bluetongue and epizootic hemorrhagic disease are regularly recorded. Single night-catches were performed at 41 sites using light suction traps at altitudes ranging from 0 to 1525 m, from March to April 2005. Five species were recorded: Culicoides imicola, Culicoides bolitinos, Culicoides enderleini, Culicoides grahamii, and Culicoides kibatiensis, among which at least the first three species are known to be involved in virus transmission to ruminants and equids. This is the first record of C. bolitinos, C. kibatiensis, and C. enderleini on the island. C. imicola was the most abundant species along the sea coast. C. bolitinos was more abundant inland and on two sites on the east coast. C. kibatiensis and C. grahamii were less abundant than the other three species and limited to two foci. Spatial distribution analysis of the different species showed that C. bolitinos, C. enderleini and C. imicola were collected at low altitudes, while the other two species were found at higher altitude. A morphological identification key for adult females and males is given, as well as cytochrome oxydase subunit I sequences. Phylogenetic reconstructions showed a clear divergence between C. bolitinos from Reunion Island and mainland Africa. This monograph will help to identify the Culicoides species in the poorly known entomological fauna of the south-western Indian Ocean region.
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Dabiré KR, Sawadogo PS, Hien DF, Bimbilé-Somda NS, Soma DD, Millogo A, Baldet T, Gouagna LC, Simard F, Lefèvre T, Diabaté A, Lees RS, Gilles JRL. Occurrence of natural Anopheles arabiensis swarms in an urban area of Bobo-Dioulasso City, Burkina Faso, West Africa. Acta Trop 2014; 132 Suppl:S35-41. [PMID: 24373897 DOI: 10.1016/j.actatropica.2013.12.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [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] [Indexed: 11/28/2022]
Abstract
The swarming behaviour of natural populations of Anopheles arabiensis was investigated by conducting transect surveys on 10 consecutive days, around dusk, from March to April and from September to October 2012 in Dioulassoba, a district of Bobo-Dioulasso city in Burkina Faso (West Africa). Swarms were observed outside, around identified larval breeding sites on the banks of the Houet River, as well as in the open-air courtyards found at the centre of many homes in the region. Swarms were found to occur in open sunlit spaces, mostly located above physical or visual cues somehow visually distinct from the surrounding area. Overall 67 and 78 swarms were observed, respectively, during the dry season (March-April) and the rainy season (September-October) of 2012, between 1.5m and 4.5m above the ground at their centre. 964 mosquitoes were collected and analysed from dry season swarms, of which most were male, and all were An. arabiensis, as were the few resting mosquitoes collected indoors. Larvae collected from breeding sites found on the banks of the Houet River mostly consisted of An. arabiensis and only a minority of Anopheles coluzzii (formerly identified as An. gambiae M form). Of 1694 mosquitoes analysed from 78 swarms in the rainy season collections, a few An. gambiae (formerly known as An. gambiae S form) males were identified, and the remainders were An. arabiensis. The majority of larvae collected during the wet season from the same breeding sites were identified as An. arabiensis followed by An. coluzzii and An. gambiae. The same pattern of species composition was observed in resting mosquitoes, though the proportion of An. arabiensis was less overwhelming. These data support the conclusion that An. arabiensis is the most prevalent species in this area, though the difference in species composition when using different population sampling techniques is noteworthy. Further studies are required for more detailed investigations of male dispersal, feeding behaviour and mating patterns in this urban setting.
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Affiliation(s)
- K R Dabiré
- IRSS/Centre Muraz, BP 390, Bobo-Dioulasso, Burkina Faso.
| | - P S Sawadogo
- IRSS/Centre Muraz, BP 390, Bobo-Dioulasso, Burkina Faso
| | - D F Hien
- IRSS/Centre Muraz, BP 390, Bobo-Dioulasso, Burkina Faso
| | | | - D D Soma
- IRSS/Centre Muraz, BP 390, Bobo-Dioulasso, Burkina Faso
| | - A Millogo
- IRSS/Centre Muraz, BP 390, Bobo-Dioulasso, Burkina Faso
| | - T Baldet
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), Montpellier, France
| | - L-C Gouagna
- IRD/UR016-CRVOI, 2 rue Maxime Rivière 97490, Sainte Clotilde, Reunion
| | - F Simard
- IRD-UMR 224, MIVEGEC, Montpellier, France
| | - T Lefèvre
- IRSS/Centre Muraz, BP 390, Bobo-Dioulasso, Burkina Faso; MIVEGEC, UMR IRD 224-CNRS 5290-Universités Montpellier 1 & 2, Centre IRD, Montpellier, France
| | - A Diabaté
- IRSS/Centre Muraz, BP 390, Bobo-Dioulasso, Burkina Faso
| | - R S Lees
- Insect Pest Control Laboratory, FAO/IAEA, A2444 Seibersdorf, Vienna, Austria
| | - J R L Gilles
- Insect Pest Control Laboratory, FAO/IAEA, A2444 Seibersdorf, Vienna, Austria
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Tran A, Ippoliti C, Balenghien T, Conte A, Gely M, Calistri P, Goffredo M, Baldet T, Chevalier V. A Geographical Information System-Based Multicriteria Evaluation to Map Areas at Risk for Rift Valley Fever Vector-Borne Transmission in Italy. Transbound Emerg Dis 2013; 60 Suppl 2:14-23. [DOI: 10.1111/tbed.12156] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Indexed: 01/10/2023]
Affiliation(s)
- A. Tran
- CIRAD; UPR Animal et Gestion Intégrée des Risques (AGIRs); Montpellier France
- CIRAD; UMR Territoires, Environnement, Télédétection et Information Spatiale (TETIS); Montpellier France
| | - C. Ippoliti
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise ‘G. Caporale’; Teramo Italy
| | - T. Balenghien
- CIRAD; UMR Contrôle des Maladies Animales Exotiques et Emergentes (CMAEE); Montpellier France
| | - A. Conte
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise ‘G. Caporale’; Teramo Italy
| | - M. Gely
- CIRAD; UPR Animal et Gestion Intégrée des Risques (AGIRs); Montpellier France
| | - P. Calistri
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise ‘G. Caporale’; Teramo Italy
| | - M. Goffredo
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise ‘G. Caporale’; Teramo Italy
| | - T. Baldet
- CIRAD; UMR Contrôle des Maladies Animales Exotiques et Emergentes (CMAEE); Montpellier France
| | - V. Chevalier
- CIRAD; UPR Animal et Gestion Intégrée des Risques (AGIRs); Montpellier France
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Viennet E, Garros C, Gardès L, Rakotoarivony I, Allène X, Lancelot R, Crochet D, Moulia C, Baldet T, Balenghien T. Host preferences of Palaearctic Culicoides biting midges: implications for transmission of orbiviruses. Med Vet Entomol 2013; 27:255-266. [PMID: 22985009 DOI: 10.1111/j.1365-2915.2012.01042.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Feeding success depends on host availability, host defensive reactions and host preferences. Host choice is a critical determinant of the intensity at which pathogens are transmitted. The aim of the current study was to describe host preferences of Palaearctic Culicoides species (Diptera: Ceratopogonidae) Latreille using traps baited with the five different host species of poultry, horse, cattle, sheep and goat. Collections were carried out nightly in July and August 2009 in western France with three replicates of a 5 × 5 randomized Latin square (five sites, five hosts). Moreover, an ultraviolet (UV) light/suction trap was operated during host-baited collections to correlate Culicoides biting rates and UV light/suction trap catches. A total of 660 Culicoides belonging to 12 species, but comprised mainly of Culicoides scoticus Downes and Kettle, Culicoides dewulfi Goetghebuer and Culicoides obsoletus Meigen, were collected on animal baits. Abundance was highest for the horse, which accounted for 95% of all Culicoides caught, representing 10 species. The horse, the largest bait, was the most attractive host, even when abundance data were corrected by weight, body surface or Kleiber's scaling factor. Culicoides obsoletus was the only dominant species attracted by birds. Both C. scoticus and C. dewulfi were collected mainly from the upper body of the horse. Finally, the quantification of host preferences allows for discussion of implications for the transmission of Culicoides-borne pathogens such as bluetongue virus.
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Affiliation(s)
- E Viennet
- UMR Contrôle des Maladies, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Montpellier, France
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Dabire KR, Sawadodgo S, Diabate A, Toe KH, Kengne P, Ouari A, Costantini C, Gouagna C, Simard F, Baldet T, Lehmann T, Gibson G. Assortative mating in mixed swarms of the mosquito Anopheles gambiae s.s. M and S molecular forms, in Burkina Faso, West Africa. Med Vet Entomol 2013; 27:298-312. [PMID: 23360106 DOI: 10.1111/j.1365-2915.2012.01049.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The molecular form composition of Anopheles gambiae Giles s.s. (Diptera: Culicidae) mating swarms and the associated mating pairs (copulae) were investigated during two rainy seasons (July to October, 2005 and July to November, 2006) in the villages of Soumousso and Vallée du Kou (VK7). Although the habitats of these villages differ markedly, sympatric populations of M and S molecular forms of An. gambiae s.s. occur in both places periodically. The main aim was to assess the degree to which these molecular forms mate assortatively. In Soumousso, a wooded savannah habitat, the majority of swarm samples consisted of only S-form males (21/28), although a few M-form males were found in mixed M- and S-form swarms. In VK7, a rice growing area, the majority of swarm samples consisted of only M-form males (38/62), until October and November 2006, when there were nearly as many mixed-form as single-form swarms. Overall, ∼60% of M- and S-form swarms were temporally or spatially segregated; the two forms were effectively prevented from encountering each other. Of the remaining 40% of swarms, however, only about half were single-form and the rest were mixed-form. Of the 33 copulae collected from mixed-form swarms, only four were mixed-form pairs, significantly fewer than expected by random pairing between forms (χ(2) = 10.34, d.f. = 2, P < 0.01). Finally, all specimens of inseminated females were of the same form as the sperm contained within their spermatheca (n = 91), even for the four mixed-form copulae. These findings indicate that assortative mating occurs within mixed-form swarms, mediated most probably by close-range mate recognition cues.
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Affiliation(s)
- K R Dabire
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, West Africa.
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Romón P, Higuera M, Delécolle JC, Baldet T, Aduriz G, Goldarazena A. Phenology and attraction of potential Culicoides vectors of bluetongue virus in Basque Country (northern Spain). Vet Parasitol 2012; 186:415-24. [DOI: 10.1016/j.vetpar.2011.11.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 11/03/2011] [Accepted: 11/07/2011] [Indexed: 11/16/2022]
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Venail R, Balenghien T, Guis H, Tran A, Setier-Rio ML, Delécolle JC, Mathieu B, Cêtre-Sossah C, Martinez D, Languille J, Baldet T, Garros C. Assessing Diversity and Abundance of Vector Populations at a National Scale: Example of Culicoides Surveillance in France After Bluetongue Virus Emergence. Parasitology Research Monographs 2012. [DOI: 10.1007/978-3-642-28842-5_4] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Venail R, Mathieu B, Setier-Rio ML, Borba C, Alexandre M, Viudes G, Garros C, Allene X, Carpenter S, Baldet T, Balenghien T. Laboratory and field-based tests of deltamethrin insecticides against adult Culicoides biting midges. J Med Entomol 2011; 48:351-357. [PMID: 21485373 DOI: 10.1603/me10178] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Bluetongue virus (BTV) is an economically important arbovirus of ruminants transmitted by Culicoides biting midges. Vector control using residual spraying or application to livestock is recommended by many authorities to reduce BTV transmission; however, the impact of these measures in terms of both inflicting mortality on Culicoides and subsequently upon BTV transmission is unclear. This study consisted of a standardized World Health Organization laboratory assay to determine the susceptibility of European Culicoides species to deltamethrin and a field trial based upon allowing individuals of a laboratory strain of Culicoides nubeculosus Meigen to feed upon sheep treated with Butox 7.5 pour-on (a deltamethrin-based topical formulation). Susceptibility in the laboratory trial was higher in colony C. nubeculosus (24-h LC90 = 0.00106%), than in field populations of Culicoides obsoletus Meigen (24-h LC90 = 0.00203%) or Culicoides imicola Kieffer (24-h LC90 = 0.00773%). In the field, the pour-on formulation was tested with a total of 816 C. nubeculosus specimens fed upon on the thigh of treated sheep. The study revealed a maximum mortality rate of 49% at 4 d postapplication, and duration of lethal effect was predicted to be as short as 10 d, despite testing being carried out with a highly susceptible strain. The reasons for this low efficacy are discussed with reference both to the potential for lack of spread of the active ingredient on the host and feeding patterns of the major potential vector species on the sheep host. Practical implications for vector control strategies during BTV incursions are also detailed.
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Affiliation(s)
- R Venail
- Entente Interdépartementale pour la Démoustication dulittoral méditerranéen (EID Méditerranée), 165 avenue Paul-Rimbaud, 34184 Montpellier Cedex 4, France.
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Saugeon C, Baldet T, Akogbeto M, Henry MC. [Will climate and demography have a major impact on malaria in sub-Saharan Africa in the next 20 years?]. Med Trop (Mars) 2009; 69:203-207. [PMID: 19545045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The purpose of this review of the literature is to present factors possibly affecting the spread of malaria in sub-Saharan Africa over the next 20 years. Malaria is a vector-borne disease that depends on environmental and human constraints. The main environmental limitations involve susceptibility of the vector (mosquitoes of the Anopheles genus) and parasite (Plasmodium falciparum) to climate. Malaria is a stable, endemic disease over most of the African continent. Climatic change can only affect a few regions on the fringes of stable zones (e.g. altitude areas or Sahel) where malaria is an unstable, epidemic disease. Higher temperatures could induce a decrease of malaria transmission in regions of the Sahel or an increase in the highlands. The extent of these overall trends will depend on the unpredictable occurrence of major meteorological phenomenon as well as on human activities affecting the environment that could lead to dramatic but limited outbreaks in some locations. The most influential human factors could be runaway demographic growth and urban development. Estimations based on modeling studies indicate that urbanization will lead to a 53.5% drop in exposure to malaria by 2030. However this reduction could be less than expected because of adaptation of Anopheles gambiae and An. arabiensis, the main vectors of malaria in sub-Saharan Africa, to the urban environment as well as increasing vector resistance to insecticides. Another unforeseeable factor that could induce unexpected malaria epidemics is mass migration due to war or famine. Finally immunosuppressive illnesses (e.g. HIV and malnutrition) could alter individual susceptibility to malaria. Social constraints also include human activities that modify land use. In this regard land use (e.g. forest clearance and irrigation) is known to influence the burden of malaria that is itself dependent on local determinants of transmission. Overall the most important social constraint for the population will be access to malarial prevention and implementation action to control this scourge.
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Affiliation(s)
- C Saugeon
- Service de coopération française, Ambassade de France
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Dabiré KR, Diabaté A, Namountougou M, Toé KH, Ouari A, Kengne P, Bass C, Baldet T. Distribution of pyrethroid and DDT resistance and the L1014F kdr mutation in Anopheles gambiae s.l. from Burkina Faso (West Africa). Trans R Soc Trop Med Hyg 2009; 103:1113-20. [PMID: 19246066 DOI: 10.1016/j.trstmh.2009.01.008] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Revised: 01/09/2009] [Accepted: 01/09/2009] [Indexed: 10/21/2022] Open
Abstract
This study reports on the distribution of pyrethroid and DDT resistance and the L1014F knockdown resistance (kdr) mutation in Anopheles gambiae s.l. populations from 21 localities in three different climatic zones of Burkina Faso from August to October 2006. The susceptibility of these populations was assessed by bioassay using DDT (4%), permethrin (1%) and deltamethrin (0.05%). Anophelesgambiae were resistant to both permethrin and DDT in the Sudanian regions but were susceptible in the central and sahelian areas and susceptible to deltamethrin at all sites except Orodara, although mortality values in some populations were close to the resistance threshold. The kdr frequency varied from 0.4 to 0.97 in populations from the Sudanian region and was lower in populations from the Sudano-sahelian and sahelian areas (0.047 to 0.54). Compared to the last survey of kdr in An. gambiae populations conducted in 2000, the kdr frequency did not differ in the S form but had increased in the M form (0.6), with an extended distribution into the Sudano-sahelian region. The frequency of kdr was also found to have increased in An. arabiensis populations (0.28), where it was formerly reported in only a single specimen. These results have practical significance for malaria vector control programs.
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Affiliation(s)
- K R Dabiré
- Insitut de Recherche en Science de la Santé (IRSS)/Centre Muraz, BP 390, Bobo-Dioulasso, Burkina Faso.
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Dabiré KR, Diabaté A, Namontougou M, Djogbenou L, Kengne P, Simard F, Bass C, Baldet T. Distribution of insensitive acetylcholinesterase (ace-1R) in Anopheles gambiae s.l. populations from Burkina Faso (West Africa). Trop Med Int Health 2009; 14:396-403. [PMID: 19254231 DOI: 10.1111/j.1365-3156.2009.02243.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To investigate through countrywide sampling at 20 localities across the three different agro-climatic zones of Burkina Faso, the distribution of the acetylcholinesterase insensitive mutation ace-1(R), which confers resistance to organophosphates (OP) and carbamates (CM) insecticides in An. gambiae s.l. METHODS Adult mosquitoes were collected by indoor aerosol spraying from August to October 2006. Specimens were identified to species by polymerase chain reaction (PCR) assay and characterized for the ace-1(R) mutation using a PCR-restriction fragment length polymorphism diagnostic. RESULTS Collected mosquitoes were a mixture of An. gambiae s.s. and An. arabiensis across the Sudan (98.3%vs. 1.7%), Sudan-sahelian (78.6%vs. 21.4%) and the Sahel (91.5%vs. 8.5%) ecotypes. The An. gambiae S-form predominated in the Sudan sites from the West (69%vs. 31% for the M form) but was not found in the Sahel (100% M form). The ace-1(R) mutation was dispersed throughout the Sudan and Sudan-sahelian localities at moderate frequency (<50%) but was absent in the Sahel. It was far more prevalent in S form than M form mosquitoes (0.32 for the S form vs. 0.036 for the M form). No An. arabiensis was detected carrying the mutation. The geographic distribution of ace-1(R) in the Sudan and Sudan-sahelian correlated with the cotton growing areas dispersed throughout the two climatic zones. CONCLUSIONS These results have special significance as OP and CM insecticides have been proposed as alternatives or additions to pyrethroids which are currently used exclusively in many vector control programmes.
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Affiliation(s)
- K R Dabiré
- Institut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso.
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Baldet T, Delécolle J, Cêtre-Sossah C, Mathieu B, Meiswinkel R, Gerbier G. Indoor activity of Culicoides associated with livestock in the bluetongue virus (BTV) affected region of northern France during autumn 2006. Prev Vet Med 2008; 87:84-97. [DOI: 10.1016/j.prevetmed.2008.06.014] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Gerbier G, Baldet T, A.Tran, Hendrickx G, Guis H, Mintiens K, Elbers A, Staubach C. Modelling local dispersal of bluetongue virus serotype 8 using random walk. Prev Vet Med 2008; 87:119-30. [DOI: 10.1016/j.prevetmed.2008.06.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Meiswinkel R, Baldet T, de Deken R, Takken W, Delécolle JC, Mellor P. The 2006 outbreak of bluetongue in northern Europe—The entomological perspective. Prev Vet Med 2008; 87:55-63. [DOI: 10.1016/j.prevetmed.2008.06.005] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Goldarazena A, Romón P, Aduriz G, Balenghien T, Baldet T, Delécolle JC. First record of Culicoides imicola, the main vector of bluetongue virus in Europe, in the Basque Country (northern Spain). Vet Rec 2008; 162:820-1. [PMID: 18567930 DOI: 10.1136/vr.162.25.820] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- A Goldarazena
- Laboratorio de Entomologia, Neiker-Tecnalia, Instituto Vasco de Investigación y Desarrollo Agrario, Apdo 46 Arkaute, E01080 Vitoria-Gasteiz, Spain
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21
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Meiswinkel R, Goffredo M, Dijkstra EGM, van der Ven IJK, Baldet T, Elbers A. Endophily in Culicoides associated with BTV-infected cattle in the province of Limburg, south-eastern Netherlands, 2006. Prev Vet Med 2008; 87:182-95. [PMID: 18672304 DOI: 10.1016/j.prevetmed.2008.06.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Culicoides were captured at a BTV-infected dairy near Gulpen in the province of Limburg (south-east Netherlands) between 14 September and 4 October 2006. Onderstepoort-type blacklight traps were used to sample Culicoides both inside and outside a partially open shed housing 11 cattle. A total of 28 light trap collections were made at the shed and yielded: 9371 Culicoides representing 11 species; >90% comprised five potential vectors of BTV and in order of abundance were Culicoides obsoletus and Culicoides scoticus (of the Obsoletus Complex), Culicoides dewulfi, Culicoides pulicaris and Culicoides chiopterus; Culicoides imicola, the principal Mediterranean (and African) vector of BTV, was absent. 2339 Culicoides representing seven species were captured inside (endophily) the cattle shed; >95% comprised the Obsoletus Complex and C. dewulfi. Conversely, the Pulicaris Complex, represented by five species and including C. pulicaris, showed strong exophily with >97% captured outside the shed. 7032 Culicoides were captured outside the shed, approximately threefold more than inside. This trend was reversed on an overcast day, when eightfold more Culicoides were captured inside; this indicates that when the light intensity outdoors is low Culicoides will attack (i) earlier in the day while cattle are still at pasture, and (ii) might follow cattle into the sheds in the late afternoon leading to elevated numbers of biting midges being trapped inside the shed during the subsequent hours of darkness. Culicoides were captured inside the shed on all 14 sampling nights. On occasion up to 33% were freshly blood fed indicating they had avidly attacked the cattle inside (endophagy); because half the cattle had seroconverted to BTV, and because no cattle were left outdoors at night, the data indicate that (i) the housing of animals in partially open buildings does not interrupt the transmission of BTV, and/or (ii) BTV is being transmitted while cattle are grazing outdoors during the day. The capture of partially engorged midges inside the shed shows they are being disturbed while feeding; this may lead to cattle being attacked repeatedly, and if these attacks include older parous BTV-infected Culicoides, may enhance virus dissemination (particularly in sheds where cattle stand close together). Endo- and exophagy by potential vector Culicoides--coupled to increased adult longevity and multiple feeding events in single (potentially) infected midges--would ensure an R0 of >1, resulting in the continued maintenance and spread of BTV within local vertebrate populations. Four light trap collections made additionally in a mature deciduous forest 70 m from the shed yielded a high proportion (48%) of gravid females amongst which 10% had incompletely digested blackened blood meals in their abdomens; the absence of this age category in Culicoides captured at the sheds indicates that all Culicoides, after engorgement, exit the buildings to undergo oogenesis elsewhere. In Europe, the blacklight trap is used widely for the nocturnal monitoring of Culicoides; a drawback to this approach is that this trap cannot be used to sample midges that are active during the day. Because diurnal biting in vector Culicoides may constitute a significant and underestimated component of BTV transmission a novel capture methodology will be required in future and is discussed briefly.
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Affiliation(s)
- R Meiswinkel
- Central Veterinary Institute of Wageningen UR, P.O. Box 65, 8200 AB Lelystad, The Netherlands.
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Dabiré KR, Diabaté A, Paré-Toé L, Rouamba J, Ouari A, Fontenille D, Baldet T. Year to year and seasonal variations in vector bionomics and malaria transmission in a humid savannah village in west Burkina Faso. J Vector Ecol 2008; 33:70-75. [PMID: 18697309 DOI: 10.3376/1081-1710(2008)33[70:ytyasv]2.0.co;2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A longitudinal entomological study was carried out from 1999 to 2001 in Lena, a humid savannah village in the western region of Burkina Faso in order to establish malaria vector bionomics and the dynamics of malaria transmission. In the first year, malaria transmission was mainly due to An. gambiae s.s., but during the two later years was due to An. funestus, which were observed in high frequency towards the end of the rainy season. PCR identification of samples of An. gambiae s.1. showed 93% to be An. gambiae s.s. and 7% An. arabiensis. An. funestus constituting more than 60% of the vectors were identified in PCR as An. funestus s.s. The persistence of intense vectorial activity in this village was probably due to the road building in a swampy area creating a semi-permanent swamp that provided large sites for larval mosquitoes. These swampy sites seemed to be more favorable for An. funestus than for An. gambiae s.s. Thus, land development must be monitored and subjected to planning to minimize vector proliferation. Such a system of planning could lead to the restriction or even elimination of the swamp that is the source of larvae developing in the heart of the village.
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Affiliation(s)
- K R Dabiré
- Institut de Recherche en Sciences de la Santé (IRSS)/Centre Muraz, BP 390, Bobo-Dioulasso, Burkina Faso
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Dabiré KR, Diabaté A, Agostinho F, Alves F, Manga L, Faye O, Baldet T. Distribution of the members of Anopheles gambiae and pyrethroid knock-down resistance gene (kdr) in Guinea-Bissau, West Africa. Bull Soc Pathol Exot 2008; 101:119-123. [PMID: 18543705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
An entomological survey conducted in 2002 in Guinea Bissau aimed i) to study the distribution of the members of Anopheles gambiae Giles complex (Diptera: Culicidae) throughout four ecological areas extended from mangrove to savannah ii) to evaluate the insecticide susceptibility status of these malaria vectors exposed to permethrin 0.75% and DDT4%, and finally iii) to investigate the occurrence and the spread of the Leu-Phe knock down resistance (kdr) gene associated with pyrethroid and DDT resistance within these vector populations. Adult female mosquitoes issued from indoor morning collections were tested using WHO procedures, test kits and impregnated papers to assess their insecticide susceptibility status. Tested specimens were identified by PCR assays and characterized for the kdr gene. Malaria vectors were mainly dominated elsewhere by An. gambiae s.s. (both S and M molecular forms) living in sympatry with low proportion of An. melas in the littoral. An. gambiae s.s. tested populations were fully susceptible both to permethrin 0.75% and to DDT 4% irrespective to their location and ecotypes. The Leu-Phe kdr mutation was detected at low frequency only in two sites respectively urban (Bissau) and Guinea-savannah (Gabu) areas. It occurred only in the S molecular form in Gabu (at the frequency of 0.14) and both in the S and M molecular forms in Bissau at the frequency of 0.06 and 0.02 respectively. These results suggested that the populations of An. gambiae s.s., the most frequent malaria vector in Guinea Bissau, still remain cross-susceptible to pyrethroids and DDT This susceptibility status and the frequency of resistance mechanism such as the kdr mutation must be monitored in the future particularly in the urban and savannah areas with continuous and intensive use of insecticides.
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Affiliation(s)
- K R Dabiré
- Laboratoire de parasitologie et d'entomologie médicale, IRSS/Centre Muraz BP 390 Bobo-Dioulasso, Burkina Faso.
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Gerbier G, Biteau-Coroller F, Grillet C, Parodi J, Zientara S, Baldet T, Guis H, Roger F. Description of the outbreak of bluetongue in Corsica in 2003, and lessons for surveillance. Vet Rec 2008; 162:173-6. [DOI: 10.1136/vr.162.6.173] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- G. Gerbier
- Campus International de Baillarguet; F-34398 Montpellier Cedex 5 France
| | | | - C. Grillet
- Campus International de Baillarguet; F-34398 Montpellier Cedex 5 France
| | - J. Parodi
- Direction Départementale des Services Vétérinaire de Corse du Sud; Immeuble Le Pélican - Residence Parc d'Azur; 20090 Ajaccio France
| | - S. Zientara
- UMR 1161 de Virologie IMRA/AFSSA/ENVA; 23 Avenue Général de Gaulle 94704 Maisons-Alfort France
| | - T. Baldet
- Campus International de Baillarguet; F-34398 Montpellier Cedex 5 France
| | - H. Guis
- Campus International de Baillarguet; F-34398 Montpellier Cedex 5 France
| | - F. Roger
- Campus International de Baillarguet; F-34398 Montpellier Cedex 5 France
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Dabiré KR, Baldet T, Diabaté A, Dia I, Costantini C, Cohuet A, Guiguemdé TR, Fontenille D. Anopheles funestus (Diptera: Culicidae) in a humid savannah area of western Burkina Faso: bionomics, insecticide resistance status, and role in malaria transmission. J Med Entomol 2007; 44:990-997. [PMID: 18047197 DOI: 10.1603/0022-2585(2007)44[990:afdcia]2.0.co;2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
An entomological survey was carried out in three humid savannah sites of western Burkina Faso (Bama, Lena, and Soumousso) to (1) update the taxonomy of the Anopheles funestus Giles group, (2) examine the role of each species in malaria transmission, (3) characterize the insecticide resistance status of this malaria vector, and (4) determine the distribution of An. funestus chromosomal forms in these areas. Polymerase chain reaction identification of the members showed the occurrence of An. leesoni Evans in Lena and An. rivulorum-like in Soumousso in addition to An. funestus s.s. Malaria transmission was ensured mainly by An. funestus s.s. both in Soumousso and Lena and by An. gambiae s.s. Giles in Bama, the rice-growing area. The insecticide resistance status performed only on An. funestus indicated that this mosquito was susceptible to pyrethroids irrespective of the study area, but it was resistant to dieldrin. Furthermore, the occurrence of the two chromosomal forms of An. funestus, namely, Kiribina and Folonzo, seemed to follow ecological setups where Kiribina predominated in the irrigated area and Folonzo was more frequent in classic savannah. This study revealed that the problematic of An. funestus taxonomy was closer to that of An. gambiae requiring more structured studies to understand its genetic ecology.
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Affiliation(s)
- K R Dabiré
- Institut de Recherche en Science de la Santé, Direction Régionale de Bobo-Dioulasso, Burkina Faso.
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Perrin A, Cetre-Sossah C, Mathieu B, Baldet T, Delecolle JC, Albina E. Phylogenetic analysis of Culicoides species from France based on nuclear ITS1-rDNA sequences. Med Vet Entomol 2006; 20:219-28. [PMID: 16796615 DOI: 10.1111/j.1365-2915.2006.00616.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) play important roles in the transmission of viral diseases affecting wild and domestic ruminants and horses, including Bluetongue (BT) and African horse sickness (AHS) respectively. In southern Europe, BT has been largely transmitted by the classical Afro-Asian vector Culicoides imicola Kieffer. However, other species such as C. obsoletus Meigen, C. scoticus Downs & Kettle and C. pulicaris Linné may also be involved in BTV transmission. As a consequence of the discovery of C. imicola followed by BTV-2 outbreaks on the island of Corsica in October 2000, further studies on these biting midges have been carried out. To better characterize the evolution and phylogenetic relations of Culicoides, molecular analysis in parallel with a morphology-based taxonomic approach were performed. Phylogenetic analyses of French Culicoides species were undertaken using the ribosomal DNA (rDNA) internal transcribed spacer 1 (ITS1) as a molecular target. This region was shown to be useful in understanding evolutionary and genetic relationships between species. Construction of several trees showed that molecular phylogeny within the genus Culicoides correlates not only with morphological-based taxonomy but also with ecological patterns.
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Affiliation(s)
- A Perrin
- CIRAD-EMVT, Campus international de Baillarguet, Montpellier, France
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Doannio JMC, Doudou DT, Konan LY, Djouaka R, Pare Toe L, Baldet T, Akogbeto M, Monjour L. [Influence of social perceptions and practices on the use of bednets in the malaria control programme in Ivory Coast (West Africa)]. Med Trop (Mars) 2006; 66:45-52. [PMID: 16615615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The National Malaria Programme in Ivory Coast has encountered difficulty in winning public acceptance of insecticide-treated bednets. We speculate that resistance to the use of bednets could be rooted in social perceptions, beliefs and practices in the communities. The purpose of this study was to identify sociocultural and environmental factors that could be used to support promotion strategies and acceptance of impregnated bednets in Ivory Coast. Survey findings confirmed that bednets were not in widespread use among the population (25%). The most widely used methods were burning mosquito coils (50%) and indoor spraying (31%). Use of impregnated bednets was low (6%). Most survey respondents (73%) indicated initial appreciation for the effectiveness of bednets in protecting against mosquitoes as a nuisance. However only 9% of respondents thought that impregnated bednets provided protection against malaria although they did not necessarily use them. Design was a determinant factor for the use, and even acceptance, of bednets. The population want rectangular, permanently impregnated bednets large enough to accommodate at least 2 persons. Cost was a major obstacle to wider use by the population. According to our data the best price for the population would be between 2000 and 2500 FCFA as compared to the current price of 3500 FCFA in Ivory Coast.
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Affiliation(s)
- J M C Doannio
- Institut Pierre Richet, 01 BP 1500, Bouaké 01, Côte d'Ivoire.
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Ouedraogo TDA, Baldet T, Skovmand O, Kabre G, Guiguemde TR. [Susceptibility of Culex quinquefasciatus to insecticides in Bobo Dioulasso, Burkina Faso]. Bull Soc Pathol Exot 2005; 98:406-10. [PMID: 16425725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
This study conducted from 1999 to 2000 in the suburbs of Bobo Dioulasso a town in the South of Burkina, aimed at investigating the susceptibility of the local population of Culex quinquefasciatus to various insecticides and proposing alternative strategies allowing a better management of insecticide resistance in the field. Eggs of C. quinquefasciatus were first collected in stagnant waste water places. The larvae were reared to early 4rth instar and tested by larval bioassays to determine the LC50/95 and the resistance ratios (RR50 and RR95) as well as their confidence intervals. A susceptible reference Strain "Slab" was used as control. Resistance was found to DDT and pyrethroids, but reduced susceptibility was found for carbamates, organophosphorates, phenyl pyrazole and in a less extend to Bacillus sphaericus. Resistance to pyrethroides is quite alarming since these insecticides are mainly used for bed net impregnation for the Roll Back malaria programme implemented in Africa. The high levels of insecticide resistance in C. quinquefasciatus suggest that alternative strategies have to be implemented to minimize the pressure of selection on resistant genes. The use of bio-larvicides (Bacillus sphaericus) alone or in rotation with different compounds may be a promising strategy for controlling C. quinquefasciatus in Bobo Dioulasso.
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Affiliation(s)
- T D A Ouedraogo
- Laboratoire de parasitologie/entomologie du Centre Muraz, Bobo Dioulasso, Burkina Faso
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Diabate A, Brengues C, Baldet T, Dabiré KR, Hougard JM, Akogbeto M, Kengne P, Simard F, Guillet P, Hemingway J, Chandre F. The spread of the Leu-Phe kdr mutation through Anopheles gambiae complex in Burkina Faso: genetic introgression and de novo phenomena. Trop Med Int Health 2005; 9:1267-73. [PMID: 15598258 DOI: 10.1111/j.1365-3156.2004.01336.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
During extensive sampling in Burkina Faso and other African countries, the Leu-Phe mutation producing the kdr pyrethroid resistance phenotype was reported in both Anopheles gambiae ss and A. arabiensis. This mutation was widely distributed at high frequency in the molecular S form of A. gambiae while it has been observed at a very low frequency in both the molecular M form and A. arabiensis in Burkina Faso. While the mutation in the M form is inherited through an introgression from the S form, its occurrence is a new and independent mutation event in A. arabiensis. Three nucleotides in the upstream intron of the kdr mutation differentiated A. arabiensis from A. gambiae ss and these specific nucleotides were associated with kdr mutation in A. arabiensis. Ecological divergences which facilitated the spread of the kdr mutation within the complex of A. gambiae ss in West Africa, are discussed.
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Affiliation(s)
- A Diabate
- Institut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso.
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Gerbier G, Hendrikx P, Roger F, Zientara S, Biteau-Coroller F, Grillet C, Baldet T, Albina E. Bluetongue control using vaccines: experience of the Mediterranean islands. Vet Ital 2004; 40:611-615. [PMID: 20422596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Following the emergence of bluetongue (BT) virus serotype 2 on the island of Corsica in 2000, annual monovalent vaccination campaigns of the ovine population were conducted between 2001 and 2003. Despite vaccination, outbreaks were reported from several areas in 2001, but since November 2001, the absence of clinical cases in Corsica proves that vaccination is effective. This experience in Corsica is examined and, using available data, compared to the situation and the vaccination strategies on other Mediterranean islands. In light of the expansion of a new serotype of BTV onto these islands, a Mediterranean information network for BT and other emerging diseases is proposed.
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Affiliation(s)
- G Gerbier
- Centre de coopération internationale en recherche agronomique pour le développement (CIRAD-EMVT) Animal Health Programme, TA 30/G, Campus International de Baillarguet, 34398 Montpellier Cedex 5, France
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Chevalier V, de la Rocque S, Baldet T, Vial L, Roger F. Epidemiological processes involved in the emergence of vector-borne diseases : West Nile fever, Rift Valley fever, Japanese encephalitis and Crimean-Congo haemorrhagic fever. REV SCI TECH OIE 2004; 23:535-55. [PMID: 15702718 DOI: 10.20506/rst.23.2.1505] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Over the past few decades, the geographical distribution of arthropod-borne zoonoses has dramatically expanded. The influence of human-induced or ecological changes on the risk of disease outbreaks is undeniable. However, few hypotheses have been proposed which address the re-emergence of these diseases, the spread of these viruses to previously uninfected areas and their establishment therein. Host and vector movements play an important role in the dissemination of pathogens, and the ability of these diseases to colonise previously uninfected areas may be explained by the diversity of hosts and vectors, the presence of favourable ecological conditions, and the successful adaptations of vectors or pathogens to new ecosystems. The objective of this paper is to describe the epidemiological processes of the vector-borne diseases Rift Valley fever, West Nile fever, Japanese encephalitis and Crimean-Congo haemorrhagic fever.
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Affiliation(s)
- V Chevalier
- Centre de coopération internationale en recherche agronomique pour le développement, Campus International de Baillarguet, 34398 Montpellier Cedex 5, France
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Baldet T, Delécolle JC, Mathieu B, de La Rocque S, Roger F. Entomological surveillance of bluetongue in France in 2002. Vet Ital 2004; 40:226-231. [PMID: 20419669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Bluetongue (BT) is an arboviral disease that appeared in the Mediterranean in 1998. In France, the principal vector, Culicoides imicola, was detected for the first time in Corsica in October 2000, a few weeks before outbreaks of BT virus serotype 2 (BTV-2). Entomological surveillance was implemented in Corsica and on mainland France in 2002. In Corsica, the aim was to study the population dynamics of C. imicola and other potential vectors. On the coastal mainland, the objective was to survey the introduction of C. imicola. One-night catches per site were performed every three weeks at 12 sites on Corsica and every month at 19 sites on the mainland. In Corsica, 84,790 Culicoides belonging to 50 species were collected over 180 nights. C. imicola accounted for 18.3% of the total captured. On the mainland, 16,197 Culicoides (44 species over 109 nights) were collected, none of which were C. imicola. The geographic and seasonal distribution of C. imicola and other species of interest are discussed in relation with their bio-ecology and environment. These datasets are essential for a better understanding of the epidemiology of BT, and to create and validate predictive models based on remote sensing in order to identify areas at risk for BT.
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Affiliation(s)
- T Baldet
- CIRAD-EMVT, TA 30 E, Campus International de Baillarguet, Montpellier, France
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Diabaté A, Baldet T, Chandre F, Dabire KR, Simard F, Ouedraogo JB, Guillet P, Hougard JM. First report of a kdr mutation in Anopheles arabiensis from Burkina Faso, West Africa. J Am Mosq Control Assoc 2004; 20:195-196. [PMID: 15264630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The leu-phe kdr mutation was detected in a specimen of Anopheles arabiensis during an extensive survey of pyrethroid resistance in An. gambiae s.l. in Burkina Faso. The detection of this mutation in An. arabiensis, which had so far been observed only in An. gambiae s.s., is important at both epidemiologic and fundamental levels. It can be useful to understand the history of this gene throughout the range of An. gambiae complex.
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Affiliation(s)
- A Diabaté
- Laboratoire d'Entomologie et de Parasitologie Centre Muraz 01 BP 390 Bobo-Dioulasso, Burkina Faso
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Hougard JM, Corbel V, N'Guessan R, Darriet F, Chandre F, Akogbéto M, Baldet T, Guillet P, Carnevale P, Traoré-Lamizana M. Efficacy of mosquito nets treated with insecticide mixtures or mosaics against insecticide resistant Anopheles gambiae and Culex quinquefasciatus (Diptera: Culicidae) in Côte d'Ivoire. Bull Entomol Res 2003; 93:491-498. [PMID: 14704095 DOI: 10.1079/ber2003261] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Only pyrethroid insecticides have so far been recommended for the treatment of mosquito nets for malaria control. Increasing resistance of malaria vectors to pyrethroids threatens to reduce the potency of this important method of vector control. Among the strategies proposed for resistance management is to use a pyrethroid and a non-pyrethroid insecticide in combination on the same mosquito net, either separately or as a mixture. Mixtures are particularly promising if there is potentiation between the two insecticides as this would make it possible to lower the dosage of each, as has been demonstrated under laboratory conditions for a mixture of bifenthrin (pyrethroid) and carbosulfan (carbamate). The effect of these types of treatment were compared in experimental huts on wild populations of Anopheles gambiae Giles and the nuisance mosquito Culex quinquefasciatus Say, both of which are multi-resistant. Four treatments were evaluated in experimental huts over six months: the recommended dosage of 50 mg m(-2) bifenthrin, 300 mg m(-2) carbosulfan, a mosaic of 300 mg m(-2) carbosulfan on the ceiling and 50 mg m(-2) bifenthrin on the sides, and a mixture of 6.25 mg m(-2) carbosulfan and 25 mg m(-2) bifenthrin. The mixture and mosaic treatments did not differ significantly in effectiveness from carbosulfan and bifenthrin alone against anophelines in terms of deterrency, induced exophily, blood feeding inhibition and overall mortality, but were more effective than in earlier tests with deltamethrin. These results are considered encouraging, as the combination of different classes of insecticides might be a potential tool for resistance management. The mixture might have an advantage in terms of lower cost and toxicity.
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Affiliation(s)
- J M Hougard
- Vector Control Research Unit (RU016), Institut de Recherche pour le Développement, Laboratoire de Lutte contre les Insectes Nuisibles (LIN), 911 Avenue Agropolis, PO Box 64501, 34394 Montpellier Cedex 5, France.
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Diabate A, Baldet T, Brengues C, Kengne P, Dabire KR, Simard F, Chandre F, Hougard JM, Hemingway J, Ouedraogo JB, Fontenille D. Natural swarming behaviour of the molecular M form of Anopheles gambiae. Trans R Soc Trop Med Hyg 2003; 97:713-6. [PMID: 16117970 DOI: 10.1016/s0035-9203(03)80110-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2003] [Revised: 06/23/2003] [Accepted: 06/23/2003] [Indexed: 10/25/2022] Open
Abstract
In Anopheles gambiae, as in most species of mosquitoes, mating is initiated in flight. The males aggregate in aerial swarms and conspecific females individually fly to these swarms where they mate with males. In this study, we investigated the swarming behaviour of A. gambiae and conducted 2 surveys in the rice field area of the Vallée du Kou in Burkina Faso in 1999 and 2002. A high number of anopheline mosquitoes were observed in this area and both molecular M and S forms of A. gambiae were found in sympatry. Swarms formed a few minutes after sunset in different places and no obvious markers were associated with their occurrence. However, swarms occurred close to cow herds generally in open flat areas, 2-3 m above the ground. Overall, 2829 anopheline mosquitoes were collected from 21 swarms composed primarily of males. A few specimens of Culex quinquefasciatus were collected from 3 swarms. Although both molecular M and S forms were found in sympatry in the village, swarms were composed almost exclusively of the molecular M form. This suggests that there are alternative swarming habits for both molecular M and S forms of A. gambiae in nature.
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Affiliation(s)
- A Diabate
- Institut de Recherche en Sciences de la Santé, Centre Muraz, B.P. 390, Bobo-Dioulasso, Burkina Faso.
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Diabaté A, Baldet T, Chandre F, Guiguemdé RT, Brengues C, Guillet P, Hemingway J, Hougard JM. First report of the kdr mutation in Anopheles gambiae M form from Burkina Faso, west Africa. Parassitologia 2002; 44:157-8. [PMID: 12701378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
The kdr mutation, conferring resistance to pyrethroid insecticides, has been reported in several West-African populations of Anopheles gambiae S form and in the M form populations from tropical forest of Benin. We report the finding of a single M specimen collected in the rice-field area of Vallée du Kou (Burkina Faso) showing the mutation at the heterozygous state. The monitoring of kdr mutation in An. gambiae forms/species is of paramount importance to implement effective malaria control tools and may greatly improve the knowledge of the relationship between and within An. gambiae populations.
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Affiliation(s)
- A Diabaté
- IRSS/Laboratoire de Parasito/Entomologie, Centre Muraz, BP 390, Bobo-Dioulasso, Burkina Faso.
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Barennes H, Baldet T, Cassel AM, Kabiré C, Kambou C. [An epidemic risk of yellow fever in Burkina Faso despite a rapid immunisation riposte: role of a multidisciplinary investigation team]. Sante 2002; 12:323-9. [PMID: 12473528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
UNLABELLED On October 8, 1999, one yellow fever (YF) case is confirmed in the South West of Burkina Faso by the Centre Muraz' virology unit. Epidemic extension is suspected as large movements of population are occurring due to troubles in Côte d'Ivoire nearby and as the Aedes vector is endemic in the region. On October 23, the Gaoua's Health Regional Head immunizes 1,000 people around the detected YF case, i.e. 70% of the estimated population and requests an epidemiological investigation. A multidisciplinary team (epidemiologist, entomologist, virologist) from the Centre Muraz, a medical research centre based in Bobo Dioulasso investigate in order to answer the following questions: are there any other or asymptomatic cases of YF? How far is the epidemic risk? Is a paper filter a valuable method for collecting blood samples? What benefit can be gained from a multidisciplinary team? METHOD An epidemiological analysis of the patient, a research of asymptomatic or ignored patient is performed (Health Centre registers, interview of the population). This includes the research of people missing the immunisation campaign. Blood samples are collected through 5 ml EDTA glass tubes or through filter paper in order to measure immunoglobuline M. A classical entomological prospecting completes the investigation. RESULTS Two possible cases are suspected in the patient's home. History of the patient's is in agreement with a local contamination. In the village 110 people missed the immunisation campaign and samples were collected in 58 people including 26 children. Among them, four (15.3%) were positive with immunoglobuline M, while there were none in the adults. Aedes Luteocephalus, a potential vector is collected through night-captures but is absent of home-water collection. Paper filter assays shows a 100% concordance with classical method. CONCLUSION The team could determine the persistency of a yellow fever epidemic risk in the region despite a rapid and adequate immunisation riposte. Due to iterative sporadic cases and due to population movement, a routine survey of YF has to be promoted as the immune status of the population, particularly in the youth, do not protect them. Collection of blood through paper filter will greatly help the routine survey and shall be confirmed during the following investigations.
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Affiliation(s)
- H Barennes
- Centre Muraz, 01 BP 390, Bobo Dioulasso, Burkina Faso.
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Chippaux JP, Bouchité B, Boussinesq M, Ranque S, Baldet T, Demanou M. Impact of repeated large scale ivermectin treatments on the transmission of Loa loa. Trans R Soc Trop Med Hyg 1998; 92:454-8. [PMID: 9850408 DOI: 10.1016/s0035-9203(98)91091-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have studied the impact of large-scale treatment with ivermectin on the transmission of loiasis in a forest village in south Cameroon where loiasis was highly endemic, with a prevalence of 30%. After one year of parasitological and entomological surveillance without treatment, all consenting residents aged > 5 years received ivermectin 200 micrograms/kg every 3 months. For ethical reasons, treatment was interrupted after 2 years, but parasitological and entomological surveillance continued for 18 months after the end of treatment. The prevalence of loiasis was reduced to < 10% and the mean microfilaraemia decreased by 90% in 2 years. The prevalence and average intensity of infection remained stable during the 18 months after treatment ended. Two vector species were identified, Chrysops dimidiata (representing about 90% of the fly population) and C. silacea. The infection rate (all stages) in Chrysops decreased by 75% and the infective rate (percentage of Chrysops harbouring third-stage larvae of Loa loa in the head) decreased by 85% in C. dimidiata and became zero in C. silacea. After the end of treatment, the infection and infective rates increased gradually. Large-scale treatment seemed an efficient method for the control of L. loa transmission provided high drug coverage was achieved. Nevertheless, because of the high risk of adverse effects when using the current microfilaricidal drugs, such a strategy remains unacceptable.
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Affiliation(s)
- J P Chippaux
- Antenne ORSTOM auprès du Centre Pasteur du Cameroun, Yaoundé, Cameroon
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Barbazan P, Baldet T, Darriet F, Escaffre H, Djoda DH, Hougard JM. Impact of treatments with Bacillus sphaericus on Anopheles populations and the transmission of malaria in Maroua, a large city in a savannah region of Cameroon. J Am Mosq Control Assoc 1998; 14:33-39. [PMID: 9599321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Simultaneously with a control of breeding sites primarily for Culex quinquefasciatus and secondarily for anophelines with Bacillus sphaericus in the town of Maroua (120,000 inhabitants) in North Cameroon, a survey of anopheline populations and of transmission rates of malaria was performed. Monthly night catches in 8 districts of the town emphasized the relation between the biting rate by Anopheles in the districts and two main factors. One factor was the distance of a district from the breeding sites, i.e., natural flooded areas along the periphery of the town or artificial breeding sites (ditches, puddles) filled with rain water during the rainy season and with water from the water network throughout the year. The second factor was the density of the habitation that reduced dispersal of female mosquitoes from the breeding sites and the risk for inhabitants to be injected because of scattered bites. The treatment with B. sphaericus was followed by a delay (2 months) in the beginning of the transmission period and a decrease in the incidence of malaria cases studied in a health facility of the town. It thus seems to be possible to reduce malaria transmission by applying B. sphaericus to the breeding sites, but this requires a good knowledge of the location and dynamics of breeding sites and an improved formulation of the pesticide.
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Thiery I, Baldet T, Barbazan P, Becker N, Junginger B, Mas JP, Moulinier C, Nepstad K, Orduz S, Sinègre G. International indoor and outdoor evaluation of Bacillus sphaericus products: complexity of standardizing outdoor protocols. J Am Mosq Control Assoc 1997; 13:218-226. [PMID: 9383761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Only one Bacillus sphaericus strain, strain 2362, is currently used commercially to control Culex larval populations. A reliable methodology, easily used, was developed to identify new strains for field application. Larvicidal activities of 3 highly mosquitocidal strains, strains C3-41, Mal, and LB24, previously selected in the laboratory, were compared with that of strain 2362 in tropical and European countries. The following steps were performed: production and titration of acetonic powders from these 4 strains on local Culex species, survey of initial and residual activity under standardized indoor and outdoor conditions, and evaluation of the efficacy of liquid formulations of the 4 strains in natural breeding sites of Culex. In indoor conditions, strain C3-41 showed the highest activity on both Culex pipiens and Culex quinquefasciatus; strain Mal was the least active. The residual activity causing 80% mortality differed from 20 to 90 days according to the strains and the country. Outdoor experiments with powders (0.02-1.6 mg/liter) were performed and the initial toxicities were similar in all cases. Residual activities were very different, from 6 to 95 days posttreatment. Liquid formulations were applied to larval habitats (from 0.1 to 10 g/m2). In tropical countries, larval recolonization in cesspits or ponds occurred after 10-35 days. In Europe, higher doses were needed in polluted water than in clear water (from 3 to 10 liter/ha) for the same control, and the time before 80% residual activity was reached was less than 9-12 days. However, in cesspits, residual activity could be observed for 12 days to 5 mo. A strain 3-5 times more active than the others in bioassays is not significantly detectable from those strains in field trials.
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Affiliation(s)
- I Thiery
- Institut Pasteur, Bactéries Entomopathogenes, Paris, France
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41
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Barbazan P, Baldet T, Darriet F, Escaffre H, Djoda DH, Hougard JM. Control of Culex quinquefasciatus (Diptera: Culicidae) with Bacillus sphaericus in Maroua, Cameroon. J Am Mosq Control Assoc 1997; 13:263-269. [PMID: 9383769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Two strategies were tested to control Culex quinquefasciatus with Bacillus sphaericus in Maroua (population 130,000), Cameroon. The treatment of all potential breeding sites (27,000) with B. sphaericus during the dry season caused up to a 90% reduction in the adult biting rate. Because of the short persistence of B. sphaericus and the occurrence of new breeding sites, unacceptable levels of adult biting rates were reached again in 5 months. In the second strategy, two treatments per year of the most productive breeding sites (10,000) stopped the biting rate increase during the rainy season. The results were only partially successful because of variations in B. sphaericus toxicity. The first treatment required 1,200 man-days of work vs. 200 for the simplified treatments. The density of breeding sites depends on the rainfall and the presence of a tap-water network. A sustained control program of Cx. quinquefasciatus will depend upon the dynamics of the principal breeding sites and an improved formulation of B. sphaericus.
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Affiliation(s)
- P Barbazan
- Antenne ORSTOM auprès du Centre Pasteur du Cameroun, Yaoundé, Cameroun
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Kamgno J, Bouchité B, Baldet T, Folefack G, Godin C, Boussinesq M. [Study of the distribution of human filariasis in West Province of Cameroon]. Bull Soc Pathol Exot 1997; 90:327-330. [PMID: 9507762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A clinical and parasitological survey of onchocerciasis and loiasis has been carried out in 38 communities in the West Province of Cameroon prior to the implementation of a mass ivermectin treatment. The highest endemicity levels of onchocerciasis were recorded in the villages located at an altitude below 1400 m, and whose inhabitants go down to the valleys for agricultural activities. Conversely, low endemicity levels were recorded in the most populated part of the study area, which is located at an altitude above 1400 m; in the latter communities, the residents cultivate the high ground not far from their houses and are thus less exposed to transmission of onchocerciasis. Despite relatively low microfilarial loads, the prevalences of nodules were fairly high; this demonstrates that in some epidemiological situations the latter indicator gives an erroneous indication of the intensity of infection in the population. The prevalence of loiasis is very low in most of the villages of the study area.
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Affiliation(s)
- J Kamgno
- ORSTOM, Centre Pasteur du Cameroun, Yaoundé, Cameroun
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