Spatial distribution of the sibling species of Anopheles gambiae sensu lato (Diptera: Culicidae) and malaria prevalence in Bayelsa State, Nigeria
Abstract Background Much of the confusing ecophenotypic plasticity of Anopheles gambiae sensu lato is attributable to the differential biological traits of the sibling species, with their heterogeneous geographical distribution, behavioral dissimilarities and divergent population dynamics. These dif...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2014-01-01
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| Series: | Parasites & Vectors |
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| Online Access: | https://doi.org/10.1186/1756-3305-7-32 |
| _version_ | 1797811793171578880 |
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| author | Amawulu Ebenezer Aline Edith Mekeu Noutcha Peter I Agi Samuel N Okiwelu Thomas Commander |
| author_facet | Amawulu Ebenezer Aline Edith Mekeu Noutcha Peter I Agi Samuel N Okiwelu Thomas Commander |
| author_sort | Amawulu Ebenezer |
| collection | DOAJ |
| description | Abstract Background Much of the confusing ecophenotypic plasticity of Anopheles gambiae sensu lato is attributable to the differential biological traits of the sibling species, with their heterogeneous geographical distribution, behavioral dissimilarities and divergent population dynamics. These differences are critical to their roles in malaria transmission. Studies were, therefore, undertaken on the spatial distribution of these species and malaria prevalence rates in Bayelsa State, September, 2008-August 2010. Methods Mosquito sampling was in 7 towns/villages in 7 Local Government Areas (LGAs) in 3 eco-vegetational zones: Fresh Water Swamp Forest (FWSF): Sagbama, Yenagoa, Kolokuma-Opokuma LGAs; Brackish Water Swamp Forest (BWSF): Ogbia, Ekeremor, Southern Ijaw LGAs; Mangrove Water Forest (MWF): Nembe LGA. Adults were collected twice quarterly by the Pyrethrum Spray Catch (PSC) technique. Anopheles was separated morphologically and the sibling species PCR- identified. Simultaneously, malaria prevalence rates were calculated from data obtained by the examination of blood smears from consenting individuals at hospitals/clinics. Results An. gambiae s.s. was dominant across the 3-eco-vegetational zones. Spatial distribution analyses by cell count and nearest neighbor techniques indicated a tendency to clustering of species. An. gambiae s.s. and An. arabiensis clustered in Ekeremor LGA while these 2 species and An. melas aggregated in Nembe. The gonotrophic (physiological) status examination revealed that 34.3, 23.5, 23.1 and 18.4% of the population were fed, unfed, gravid and half gravid respectively. The highest malaria prevalence rates were obtained at Kolokuma-Opokuma and Nembe LGAs. Variation in prevalence rates among LGAs was significant (t = 5.976, df = 6, p-value = 0.002, p < 0.05). The highest prevalence rate was in the age group, 30-39 yrs, while the lowest prevalence was in the 0-9 yrs group. Conclusion High malaria prevalence rates were associated with An. gambiae s.s. either in allopatry or sympatry across eco-vegetational zones. In areas where the sibling species clustered, they probably formed nidi for transmission. Socio-economic conditions might have contributed to reduced prevalence in Yenagoa, State Capital. |
| first_indexed | 2024-03-13T07:27:59Z |
| format | Article |
| id | doaj.art-fa06bd5c540342e395b8ceb3bda9bed1 |
| institution | Directory Open Access Journal |
| issn | 1756-3305 |
| language | English |
| last_indexed | 2024-03-13T07:27:59Z |
| publishDate | 2014-01-01 |
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| spelling | doaj.art-fa06bd5c540342e395b8ceb3bda9bed12023-06-04T11:16:20ZengBMCParasites & Vectors1756-33052014-01-01711610.1186/1756-3305-7-32Spatial distribution of the sibling species of Anopheles gambiae sensu lato (Diptera: Culicidae) and malaria prevalence in Bayelsa State, NigeriaAmawulu Ebenezer0Aline Edith Mekeu Noutcha1Peter I Agi2Samuel N Okiwelu3Thomas Commander4Department of Animal and Environmental Biology, University of Port-HarcourtDepartment of Animal and Environmental Biology, University of Port-HarcourtDepartment of Animal and Environmental Biology, University of Port-HarcourtDepartment of Animal and Environmental Biology, University of Port-HarcourtDepartment of Biological Sciences, Niger Delta University, Wilberforce IslandAbstract Background Much of the confusing ecophenotypic plasticity of Anopheles gambiae sensu lato is attributable to the differential biological traits of the sibling species, with their heterogeneous geographical distribution, behavioral dissimilarities and divergent population dynamics. These differences are critical to their roles in malaria transmission. Studies were, therefore, undertaken on the spatial distribution of these species and malaria prevalence rates in Bayelsa State, September, 2008-August 2010. Methods Mosquito sampling was in 7 towns/villages in 7 Local Government Areas (LGAs) in 3 eco-vegetational zones: Fresh Water Swamp Forest (FWSF): Sagbama, Yenagoa, Kolokuma-Opokuma LGAs; Brackish Water Swamp Forest (BWSF): Ogbia, Ekeremor, Southern Ijaw LGAs; Mangrove Water Forest (MWF): Nembe LGA. Adults were collected twice quarterly by the Pyrethrum Spray Catch (PSC) technique. Anopheles was separated morphologically and the sibling species PCR- identified. Simultaneously, malaria prevalence rates were calculated from data obtained by the examination of blood smears from consenting individuals at hospitals/clinics. Results An. gambiae s.s. was dominant across the 3-eco-vegetational zones. Spatial distribution analyses by cell count and nearest neighbor techniques indicated a tendency to clustering of species. An. gambiae s.s. and An. arabiensis clustered in Ekeremor LGA while these 2 species and An. melas aggregated in Nembe. The gonotrophic (physiological) status examination revealed that 34.3, 23.5, 23.1 and 18.4% of the population were fed, unfed, gravid and half gravid respectively. The highest malaria prevalence rates were obtained at Kolokuma-Opokuma and Nembe LGAs. Variation in prevalence rates among LGAs was significant (t = 5.976, df = 6, p-value = 0.002, p < 0.05). The highest prevalence rate was in the age group, 30-39 yrs, while the lowest prevalence was in the 0-9 yrs group. Conclusion High malaria prevalence rates were associated with An. gambiae s.s. either in allopatry or sympatry across eco-vegetational zones. In areas where the sibling species clustered, they probably formed nidi for transmission. Socio-economic conditions might have contributed to reduced prevalence in Yenagoa, State Capital.https://doi.org/10.1186/1756-3305-7-32An. gambiae s.lSibling speciesMalaria prevalenceGISDistributionBayelsa- State |
| spellingShingle | Amawulu Ebenezer Aline Edith Mekeu Noutcha Peter I Agi Samuel N Okiwelu Thomas Commander Spatial distribution of the sibling species of Anopheles gambiae sensu lato (Diptera: Culicidae) and malaria prevalence in Bayelsa State, Nigeria Parasites & Vectors An. gambiae s.l Sibling species Malaria prevalence GIS Distribution Bayelsa- State |
| title | Spatial distribution of the sibling species of Anopheles gambiae sensu lato (Diptera: Culicidae) and malaria prevalence in Bayelsa State, Nigeria |
| title_full | Spatial distribution of the sibling species of Anopheles gambiae sensu lato (Diptera: Culicidae) and malaria prevalence in Bayelsa State, Nigeria |
| title_fullStr | Spatial distribution of the sibling species of Anopheles gambiae sensu lato (Diptera: Culicidae) and malaria prevalence in Bayelsa State, Nigeria |
| title_full_unstemmed | Spatial distribution of the sibling species of Anopheles gambiae sensu lato (Diptera: Culicidae) and malaria prevalence in Bayelsa State, Nigeria |
| title_short | Spatial distribution of the sibling species of Anopheles gambiae sensu lato (Diptera: Culicidae) and malaria prevalence in Bayelsa State, Nigeria |
| title_sort | spatial distribution of the sibling species of anopheles gambiae sensu lato diptera culicidae and malaria prevalence in bayelsa state nigeria |
| topic | An. gambiae s.l Sibling species Malaria prevalence GIS Distribution Bayelsa- State |
| url | https://doi.org/10.1186/1756-3305-7-32 |
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