Breeding sites of Culex quinquefasciatus (Say) were investigated during a World Bank Assisted Project on Integrated Vector Management (IVM ) for malaria control at 5 v illages (Ipo, Ozuaha, Oman wa, Omademe, Ub ima) in the Ikwerre Local Govern ment Area (LGA ). The study was in the rainy season, June-September, 2009, in ru ral lowland rainforest, Rivers State, Nigeria. Samp ling was undertaken daily in a randomly selected (100 m x 100 m) grid in each village. Nu mber of Cx. quinquefasciatus (Say) immatures was appro ximately 6-fold that of An. gambiae s.l. Nearly 80% of Cx. quinquefasciatus immatures were fro m container-type breeding sites (metal, p lastic containers, "calabashes", tyres) and least fro m phytotelmata. The differences were significant (F Cal =35695636; F Tab =39.86; d f 1, 1; p<0.01). Plastic containers were the preferred site-type in this category. The container-type breeding sites also yielded the highest number of immatures per breeding site. In the pools breeding site-types, approximately 55% were fro m puddles and 45% fro m gutters; the difference was not significant (F Cal =334975; F Tab =39.86; df 1,1; p >0.01). In the phytotelmata breeding site-types, about 67% of Cx. quinquefasciatus immatures were fro m depressions on trees; the difference in total numbers among site-types was significant (F Cal =2.47x10 8 ; F Tab =39.86; df 1,1; p<0.01). The container-type breeding sites yielded approximately 90% of immatures at Omanwa, but decreased to 60% at Omademe. In contrast, nearly 70% of immatures were fro m pools at Ozuaha and 80% fro m phytotelmata at Ub ima. These variat ions were significant (F Cal =4305.94; F Tab =39.86; df 1,1; p<0.01). The results indicate that Cx. quinquefasciatus had invaded rural areas and their breed ing sites ubiquitous and variable among villages, highlighting the needs for studies locally, prior to larviciding.
A ground survey to map the distribution of Glossina prior to the initiation of a control programme was undertaken in an area of more than 100 000 km 2 in the Sudan and Guinea savanna zones of Mali. The area extends from 1T13' to 14°15'N. and 5°53' to 10°24'W. The ChallierLaveissiere trap was the main survey tool, but other methods were used when the traps did not catch flies in areas suspected of being suitable for Glossina. The results are compared with existing distribution maps of the area, including one based solely on interpretations of earth satellite photography of the area. Infestation by G. morsitans submorsitans Newst. was continuous west of 8°20'W. and intermittent east of this. Apparent recent advances of G. m. submorsitans and G. palpalis gambiensis Vanderplank were noted, but G. tachinoides Westw. seemed to have receded. Possible reasons for these differences between species are discussed.
BackgroundMuch 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.MethodsMosquito 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.ResultsAn. 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.ConclusionHigh 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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.