Skip to main content Accessibility help
×
Home

Spatial Distribution of Anopheles gambiae and Anopheles funestus and Malaria Transmission in Suba District, Western Kenya

  • Josephat I. Shililu (a1) (a2), Charles M. Mbogo (a3), Clifford M. Mutero (a1) (a4), James T. Gunter (a5), Chris Swalm (a6), James L. Regens (a5), Joseph Keating (a7), Guiyun Yan (a8), John I. Githure (a1) and John C. Beier (a9)...

Abstract

The study reported here evaluated the distribution, relative abundance, and malaria transmission potential of Anopheles mosquitoes at 30 sites representing different ecological strata in western Kenya. Seasonal variation in anopheline densities and transmission potential, as expressed by Entomological inoculation rates (EIR), was investigated. Of the 6491 indoor resting anopheline mosquitoes collected at the 30 sites, 91.3 % (n = 5926) were An. gambiae s.l. and 8.7 % (n = 565) were An. funestus with an average house density of 6.58 and 0.63, respectively. Analysis of the data indicated significant variation in mosquito densities between study sites, species and season. High densities of both An. gambiae and An. funestus were recorded in the northern and northeastern parts of the district, while generally low densities were recorded in the south. Anopheles gambiae s.s. and An. arabiensis comprised 60.3 % (n = 3573) and 39.7 % (n = 2352) of the total number of An. gambiae s.l. mosquitoes collected, respectively. The composition of the An. gambiae s.l. sibling species showed temporal and spatial variation. Entomologic inoculation rates were estimated at 1.55 and 0.12 infective bites per person per month for An. gambiae s.l. and An. funestus, respectively. This study reveals considerable seasonal and site-specific variation in vector distribution, composition and transmission potential. Application of control interventions must therefore consider seasonal variations since the vectorial system changes quite rapidly over a short period of time.

L'étude présentée ici évalue la distribution, l'abondance relative, et le potentiel de transmission du paludisme par des moustiques anophèles dans 30 localités représentatives des différentes conditions écologiques de l'Ouest du Kenya. La variation saisonnière des densités d'anophèles et du potentiel de transmission, exprimées par les taux d'inoculations Entomologiques (EIR), est examinée. Sur les 6491 anophèles récoltées au repos à l'intérieur des maisons dans les 30 localités, 91,3% (n=5926) sont des An. gambiae s.l. et 8,7% sont des An. funeslus avec une densité moyenne par maison de 6,58 et 0,63 respectivement. L'analyse des données indique une variation significative des densités de moustiques entre les sites étudiés, l'espèce et la saison. Des densités élevées à la fois d'An, gambiae s.l. et An. funestus ont été observées dans le nord et le nord est du district, alors que des densités généralement faibles ont été observées dans le sud. An. gambiae s.S. et An. arabiensis représentent respectivement 60,3% (n=3573) et 39,7% (n=2352) du nombre total de An. gambiae s.l récolté. La composition des 2 espèces d'An, gambiae s.l. montre une variation temporelle et spatiale. Les taux d'inoculations entomologiques sont estimés respectivement à 1,55 et 0,12 piqûres infestantes par personne et par mois pour'An. gambiae s.l. et An. funestus. Cette étude révèle une variation considérable de la distribution, de la composition et du potentiel de transmission des vecteurs selon la saison et la localité. La réalisation de campagnes de lutte doit par conséquent prendre en compte les variations saisonnières puisque le complexe vectoriel change très rapidement en un temps très court.

Copyright

References

Hide All
Attenborough, R. D., Burkot, T. R. and Gardner, D. S. (1997) Altitude and the risk bites from mosquitoes infected with malaria and filariasis among the Mianmin people of Papua New Guinea. Trans. R. Trop. Med. Hyg. 91, 810.
Beier, J. C., Perkins, P. V., Wirtz, R. A., Whitmire, R. E., Mugambi, M. and Hockmeyer, W. T. (1987) Field evaluation of an enzyme-linked immunosorbent assay (ELISA) for Plasmodium falciparum sporozoite detection in anopheline mosquitoes from Kenya. Am. J. Trop. Med. Hyg. 36, 459468.
Beier, J. C., Perkins, P. V., Onyango, F. K., Gargan, T. P., Oster, M. C., Whitmire, R. E., Koech, D. K. and Clifford, R. R. (1990) Characterization of malaria transmission by Anopheles (Diptera: Culicidae) in western Kenya in preparation for malaria vaccine trials, J. Med. Entomol. 27, 570577.
Coetzee, M., Craig, M. and Le Sueur, D. (2000) Distribution of African malaria mosquitoes belonging to the Anopheles gambiae complex. Parasitol Today 16, 7477.
Collins, F. H., Mendez, M. A., Rasnussen, M., Mehaffey, P. C., Besansky, N. J. and Finnerty, V. (1987) A ribosomal RNA gene probe differentiates member species of the Anopheles gambiae complex. Am. J. Trop. Med. Hyg. 37, 3741.
Gillies, M. T. and Coetzee, M. (1987) A supplement of the Anopheline of Africa South of the Sahara (Afrotropical Region). Pub. S. Afr. Inst. Med. Res, 55.
Githeko, A. K., Service, M. W., Mbogo, C. M., Atieli, F. K. and Juma, F. O. (1993) Plasmodium falciparum sporozoite and entomological inoculation rates at Ahero rice irrigation scheme and the Miwani sugarbelt in western Kenya. Ann. Trop. Med. Parasitol. 87, 379391.
Highton, R. B., Bryan, J. H., Boreham, P. F. L. and Chandler, J. A. (1979) Studies on the sibling species Anopheles gambiae Giles and An. arabiensis Patton (Diptera: Culicidae) in the Kisumu area, Kenya. Bull. Entomol. Res. 69, 4353.
Kenya National Bureau of Statistics (1999) Executive Report: Summary Statistics. Government Press, Nairobi, Kenya.
Lindblade, A. K., Walker, E. D. and Wilson, M. L. (2000) Early warning of malaria epidemics in African highlands using Anopheles (Diptera: Culicidae) indoor resting densities, J. Med. Entomol. 37, 664674.
Lindsay, S. W., Campbell, H., Adiainhah, J. H., Greenwood, A. M., Bangali, S. E. and Greenwood, B. M. (1990) Malaria in a peri-urban area of the Gambia. Ann. Trop. Med. Parasitol. 84, 555562.
Mbogo, C. M., Snow, R. W., Khamala, C. P., Kabiru, E. W., Ouma, J. H., Githure, J. I., Marsh, K. and Beier, J. C. (1995) Relationships between Plasmodium falciparum transmission by vector populations and the incidence of severe disease at nine sites on the Kenya coast. Am. J. Trop. Med. Hyg. 52, 201206.
Minakawa, N., Mutero, C. M., Githure, J. I., Beier, J. C. and Yan, G. (1999) Spatial distribution and habitat characterization of anopheline mosquito larvae in western Kenya. Am. J. Trop. Med. Hyg. 37, 3741.
Mutero, C. M., Ouma, J. H., Agak, B. K., Wanderi, J. A. and Copeland, R. S. (1998) Malaria prevalence and use of self-protection measures against mosquitoes in Suba District, Kenya. East Afr. Med. J. 75, 1116.
Omumbo, J., Ouma, J. H., Rapuoda, B., Craig, M. H., Le Sueur, D. and Snow, R. W. (1998) Mapplng malaria transmission using geographical information systems (GIS): An example from Kenya. Trop. Med. Parasitol. 92, 721.
Petrarca, V., Beier, J. C., Onyango, F. K., Koros, J. K., Asiago, C. M., Koech, D. K. and Roberts, C. R. (1991) Species composition of Anopheles gambiae complex (Diptera: Culicidae) at two sites in western Kenya, J. Med. Entomol. 28, 307313.
Scott, J. A., Brogdon, W. G. and Collins, F. K. (1993) Identification of single specimens of the Anopheles gambiae complex by polymerase chain reaction. Am. J. Trop. Med. Hyg. 49, 520529.
Shililu, J. I., Maier, W. A., Seitz, H. M. and Orago, A. S. (1998) Seasonal density, sporozoite rates and entomological inoculation rates of Anopheles gambiae and Anopheles funestus in a high-altitude sugarcane zone in Western Kenya. Trop. Med. Int. Health. 3, 706710.

Keywords

Spatial Distribution of Anopheles gambiae and Anopheles funestus and Malaria Transmission in Suba District, Western Kenya

  • Josephat I. Shililu (a1) (a2), Charles M. Mbogo (a3), Clifford M. Mutero (a1) (a4), James T. Gunter (a5), Chris Swalm (a6), James L. Regens (a5), Joseph Keating (a7), Guiyun Yan (a8), John I. Githure (a1) and John C. Beier (a9)...

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed