Your search found 4 records
1 Kibret, S.; Alemu, Y.; Boelee, Eline; Tekie, H.; Alemu, D.; Petros, B. 2010. The impact of a small-scale irrigation scheme on malaria transmission in Ziway area, central Ethiopia. Tropical Medicine and International Health, 15(1):41-50. [doi: https://doi.org/10.1111/j.1365-3156.2009.02423.x]
Small scale systems ; Irrigation schemes ; Waterborne diseases ; Malaria ; Entomology ; Surveys ; Habitats ; Villages / Ethiopia / Ziway Area / Rift Valley / Abene-Girmamo / Woshgulla
(Location: IWMI HQ Call no: e-copy only Record No: H042532)
(0.17 MB)
Objective To assess the impact of a small-scale irrigation scheme in Ziway area, a semi-arid area in the Central Ethiopian Rift Valley, on malaria transmission. method Parasitological, entomological and socio-economic studies were conducted in a village with and a village without irrigation. Blood smear samples were taken from individuals during the dry and wet seasons of 2005 / 2006. Socio-economic data were collected from household heads and key agricultural and health informants through interviews and questionnaires. Larval and adult mosquitoes were sampled during the dry and short wet seasons of 2006. Female anopheline mosquitoes were tested by enzyme-linked immunosorbent assay for blood meal sources and sporozoite infections. results Malaria prevalence was higher in the irrigated village (19%, P < 0.05) than the non-irrigated village (16%). In the irrigated village, malaria prevalence was higher in the dry season than in the wet season while the reverse occurred in the non-irrigated village. Households with access to irrigation had larger farm land sizes and higher incomes, but also higher prevalence of malaria. Larval and adult abundance of the malaria vectors, Anopheles arabiensis and Anopheles pharoensis, was higher in the irrigated than in the non-irrigated village throughout the study period. Furthermore, the abundance of An. pharoensis was significantly higher than that of An. arabiensis during the dry irrigated period of the year. Canal leakage pools, irrigated fields and irrigation canals were the major breeding habitats of the two vector mosquitoes. Plasmodium falciparum sporozoite infection rates of 1.18% and 0.66% were determined for An. arabiensis and An. pharoensis in the irrigated village. Peak biting activities of the vectors occurred before 22:00 h, which is a source of concern that the effectiveness of ITNs may be compromised as the mosquitoes feed on blood before people go to bed. conclusion Irrigation schemes along the Ethiopian Rift Valley may intensify malaria by increasing the level of prevalence during the dry season. To reduce the intensity of malaria transmission in the smallscale irrigation schemes currently in operation in Ethiopia, year-round source reduction by using proper irrigation water management, coupled with health education, needs to be incorporated into the existing malaria control strategies.
2 Kibret, S.; Boelee, Eline; Petros, B.; Tekie, H.. 2010. Entomological studies on the impact of a small-scale irrigation scheme on malaria transmission around Ziway, central Ethiopia. Ethiopian Journal of Development Research, 32(1):107-134 (Special issue with contributions by IWMI authors).
Irrigation schemes ; Malaria ; Anopheles ; Entomology ; Surveys ; Habitats ; Waterborne diseases ; Public health ; Rural areas ; Villages / Ethiopia / Ziway
(Location: IWMI HQ Call no: PER Record No: H043258)
(0.14 MB)
Larval and adult anophelines were sampled around Ziway, Central Ethiopia. Throughout the study period, significantly higher densities of Anopheles pharoensis and An. arabiensis were found in the village with irrigation than in the village without. Canal leakage pools, irrigated fields and irrigation canals were the major sources of Anopheles larvae. Most adult anophelines were found to feed on humans, especially before 22hrs, and up to 1% were infected with malaria parasites. This study demonstrated that due to poor maintenance, irrigation schemes create conducive breeding grounds for malaria vector mosquitoes and hence increase the risk of malaria transmission.
3 Teklu, B. M.; Tekie, H.; McCartney, Matthew; Kibret, S. 2010. The effect of physical water quality and water level changes on the occurrence and density of Anopheles mosquito larvae around the shoreline of the Koka reservoir, central Ethiopia. Hydrology and Earth System Sciences, 14(12):2595-2603. [doi: https://doi.org/10.5194/hess-14-2595-2010]
Mosquitoes ; Anopheles ; Breeding places ; Reservoirs ; Malaria / Africa / Ethiopia / Koka Reservoir / Ejersa Village / Kuma Village
(Location: IWMI HQ Call no: e-copy only Record No: H043432)
http://www.hydrol-earth-syst-sci.net/14/2595/2010/hess-14-2595-2010.pdf
https://vlibrary.iwmi.org/pdf/H043432.pdf
https://vlibrary.iwmi.org/pdf/H043432.pdf
(0.52 MB)
Entomological studies to determine the effect of the physical characteristics of mosquito larval breeding water bodies and reservoir water level changes on the occurrence of Anopheles mosquito larvae were conducted in two villages at Koka reservoir in central Ethiopia between August and December 2007. Of the two study villages, Ejersa is located close to the reservoir, and Kuma is 5 km away from it. Data on the type, number and physical characteristics of Anopheles larval breeding habitat, species composition and densities of anopheles mosquitoes in and around the study villages were investigated and recorded. Meteorological and reservoir water level data were compared with availability of Anopheles larval breeding sites and densities. Entomological data, derived from weekly larval collections, showed that Anopheles pharoensis Theobald, Anopheles gambiae s.l. Giles, Anopheles coustani Laveran and Anopheles squamosus Theobald were breeding in the study area. The mean larval density of An. gambiae s.l. in this study was higher in slightly turbid and shallow aquatic habitat than in turbid and relatively deep aquatic habitat. The density of An. pharoensis in habitat with floating vegetation and with relatively shady conditions was significantly higher than that of less shaded aquatic habitat and greater emergent vegetation. There was also a positive correlation between the occurrence of Anopheles larvae with the water and daily minimum atmospheric temperature. Similarly at Ejersa, over the sampling period, there was a positive correlation between falling reservoir water levels and the number of positive breeding habitats. These results confirm that physical characteristics of the water bodies play an important role in the species composition, total Anopheles larval count, and the density of Anopheles mosquitoes. Suitable breeding habitat in the vicinity of the reservoir village was strongly associated with the reservoir. This is particularly important for An. pharoensis and An. gambiae s.l. which are important vectors of malaria in the area.
4 Kibret, S.; Petros, B.; Boelee, Eline; Tekie, H.. 2008. Entomological studies on the impact of a small-scale irrigation scheme on malaria transmission around Ziway, Ethiopia. In Awulachew, Seleshi Bekele; Loulseged, Makonnen; Yilma, Aster Denekew (Comps.). Impact of irrigation on poverty and environment in Ethiopia: draft proceedings of the symposium and exhibition, Addis Ababa, Ethiopia, 27-29 November 2007. Colombo, Sri Lanka: International Water Management Institute (IWMI). pp.418-438.
Malaria ; Anopheles pharoensis ; Anopheles arabiensis ; Entomology ; Surveys ; Irrigation schemes ; Small scale systems / Ethiopia / Ziway
(Location: IWMI HQ Call no: e-copy only Record No: H044138)
(0.22 MB)
To evaluate the impact of a small-scale irrigation scheme on the level of malaria transmission in a semi-arid area, entomological studies were conducted in Zeway area, Central Ethiopia. Larval and adult anophelines were sampled during the dry and short-rainy seasons from irrigated and non-irrigated villages. Overall, significantly higher density of Anopheles larvae were found during the dry season in the irrigated village (Mean = 38.3 larvae/100 dips) than the non-irrigated village (7.4 larvae/100 dips). Canal leakage pools, irrigated fields and irrigation canals were the major sources of Anopheles mosquitoes. Larval and adult Anopheles pharoensis and An. arabiensis, principal malaria vectors in Ethiopia, were more abundant in the irrigated village than the non-irrigated village throughout the study period. Hourly light trap catches revealed that peak indoor and outdoor biting activities of An. arabiensis and An. pharoensis occurred during the early period of the night before the local inhabitants retire to bed. The majority of blood-engorged An. arabiensis (0.78) and An. pharoensis (0.69) had fed on humans, suggesting that their highly anthropophilic nature in Zeway area. Plasmodium falciparum infection rates of 1.02% and 0.54% were determined for An. arabiensis and An. pharoensis, respectively, in the irrigated village. This study demonstrated that due to poorly maintained irrigation structures, the irrigation scheme created conducive breeding grounds for malaria vector species, particularly during the dry season. Consequently, the period of malaria transmission might possibly extend from seasonal to year-round, involving the dry season. Proper water management coupled with environmental management such as source reduction could reduce vector abundance and hence malaria transmission in the irrigation schemes.
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