Integrated mosquito larval source management reduces larval numbers in two highland villages in western Kenya

BMC Public Health

Willem Takken¹  Wolfgang R Mukabana²  Andrew Githeko³  Susan S Imbahale⁴ 

[1]Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH, Wageningen, The Netherlands

[2]School of Biological Sciences, University of Nairobi, P.O. Box 30197-00100 GPO, Nairobi, Kenya

[3]Kenya Medical Research Institute, Centre for Global Health Research, P.O Box 1578-40100, Kisumu, Kenya

[4]School of Pure and Applied Sciences, Kenya Polytechnic University College, P.O Box 52428-00200, Nairobi, Kenya

关键词: Kenya;    Arrow root;    Gambusia affinis;    Drainage;    Bacillus thuringiensis var israelensis (Bti);    Larval source management;    Anopheles spp;   

Others  :  1163613
DOI  :  10.1186/1471-2458-12-362

 received in 2011-11-10, accepted in 2012-05-18,  发布年份 2012

【 摘 要 】

Background

In western Kenya, malaria remains one of the major health problems and its control remains an important public health measure. Malaria control is by either use of drugs to treat patients infected with malaria parasites or by controlling the vectors. Vector control may target the free living adult or aquatic (larval) stages of mosquito. The most commonly applied control strategies target indoor resting mosquitoes. However, because mosquitoes spend a considerable time in water, targeting the aquatic stages can complement well with existing adult control measures.

Methods

Larval source management (LSM) of malaria vectors was examined in two villages i.e. Fort Ternan and Lunyerere, with the aim of testing strategies that can easily be accessed by the affected communities. Intervention strategies applied include environmental management through source reduction (drainage of canals, land levelling or by filling ditches with soil), habitat manipulation (by provision of shading from arrow root plant), application of Bacillus thuringiensis var israelensis (Bti) and the use of predatory fish, Gambusia affinis. The abundance of immature stages of Anopheles and Culex within intervention habitats was compared to that within non-intervention habitats.

Results

The findings show that in Fort Ternan no significant differences were observed in the abundance of Anopheles early and late instars between intervention and non-intervention habitats. In Lunyerere, the abundance of Anopheles early instars was fifty five times more likely to be present within non-intervention habitats than in habitats under drainage. No differences in early instars abundance were observed between non-intervention and habitats applied with Bti. However, late instars had 89 % and 91 % chance of being sampled from non-intervention rather than habitats under drainage and those applied with Bti respectively.

Conclusion

Most of these interventions were applied in habitats that arose due to human activities. Involvement of community members in control programs would be beneficial in the long term once they understand the role they play in malaria transmission. Apart from the need for communities to be educated on their role in malaria transmission, there is a need to develop and test strategies that can easily be accessed and hence be used by the affected communities. The proposed LSM strategies target outdoor immature mosquitoes and hence can complement well with control measures that target indoor resting vectors. Therefore inclusion of LSM in Integrated Vector Management (IVM) program would be beneficial.

【 授权许可】

   
2012 Imbahale et al.; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

Figure 2.

【 参考文献 】

• [1]Okech BA, Gouagna LC, Walczak E, Kabiru EW, Beier JC, Yan G, et al.: The development of Plasmodium falciparum in experimentally infected Anopheles gambiae (Diptera: Culicidae) under ambient microhabitat temperature in western Kenya. Acta Trop 2004, 92:99-108.
• [2]Minakawa N, Mutero CM, Githure JI, Beier JC, Yan G: Spatial distribution and habitat characterization of anopheline mosquito larvae in Western Kenya. Am J Trop Med Hyg 1999, 61:1010-1016.
• [3]Gimnig JE, Ombok M, Kamau L, Hawley WA: Characteristics of Larval Anopheline (Diptera: Cilicidae) Habitats in Western Kenya. J Med Entomol 2001, 38:282-288.
• [4]Awolola TS, Oduola AO, Obansa JB, Chukwurar NJ, Unyimadu JP: Anopheles gambiae s.s. breeding in polluted water bodies in urban Lagos, southwestern Nigeria. J Vector Borne Dis 2007, 44:241-244.
• [5]Castro MC, Kanamori S, Kannady K, Mkude S, Killeen GF, Fillinger U: The Importance of Drains for the Larval Development of Lymphatic Filariasis and Malaria Vectors in Dar es Salaam, United Republic of Tanzania. PLoS Neglect Trop Dis 2010, 4:e693.
• [6]Ndenga BA, Simbauni JA, Mbugi JP, Githeko AK, Fillinger U: Productivity of Malaria Vectors from Different Habitat Types in the Western KenyaHighlands. PLoS One 2011, 6(4):e19473.
• [7]Imbahale SS, Paaijmans KP, Mukabana WR, Lammeren R, Githeko AK, Takken W: A longitudinal study on Anopheles mosquito larval abundance in distinct geographical and environmental settings in western Kenya. Malar J 2011, 10:81. BioMed Central Full Text
• [8]Minakawa N, Sonye G, Dida GO, Futami K, Kaneko S: Recent reduction in the water level of Lake Victoria has created more habitats for Anopheles funestus. Malar J 2008, 7:119. BioMed Central Full Text
• [9]Chen H, Githeko AK, Zhou G, Githure JI, Yan G: New records of Anopheles arabiensis breeding on the Mount Kenya highlands indicate indigenous malaria transmission. Malar J 2006, 5:17. BioMed Central Full Text
• [10]Garnham PCC: Malaria epidemics at exceptionally high altitudes in Kenya. British Med J 1945, 11:45-47.
• [11]Lindblade KA, Walker ED, Onapa AW, Katungu J, Wilson ML: Land use change alters malaria transmission parameters by modifying temperature in a highland area of Uganda. Trop Med Int Health 2000, 5:263-274.
• [12]Malakooti MA, Biomndo K, Shanks GD: Re-emergence of epidemic malaria in the highlands of western Kenya. Emerg Infect Dis 1998, 4:671-676.
• [13]Zhou G, Minakawa N, Githeko AK, Yan G: Association between climate variability and malaria epidemics in the East African highlands. Proc Nat Acad Sci USA 2004, 101:2375-2380.
• [14]Cox J: Mapping malaria risk in the highlands of Africa. MARA/HIMAL, London UK; 1999.
• [15]Balls MJ, Bodker R, Thomas CJ, Kisinza W, Msangeni HA, Lindsay SW: Effect of topography on the risk of malaria infection in the Usambara Mountains, Tanzania. Trans Royal Soc Trop Med Hyg 2004, 98:400-408.
• [16]Munga S, Minakawa N, Zhou G, Mushinzimana E, Barrack OO, Githeko AK, et al.: Association between land cover and habitat productivity of malaria vectors in western Kenyan highlands. Am J Trop Med Hyg 2006, 74:69-75.
• [17]Das P: Infectious disease surveillance update. Lancet Infect Dis 2004, 4:7.
• [18]Ernst KC, Adoka SO, Kowuor DO, Wilson ML, John CC: Malaria hotspot areas in a highland Kenya site are consistent in epidemic and non-epidemic years and are associated with ecological factors. Malar J 2006, 5:78. BioMed Central Full Text
• [19]Githeko AK, Ndegwa W: Predicting malaria epidemics in the Kenyan highlands using climate data: a tool for decision makers. Global Change and Human Health 2001, 2(1):54-63.
• [20]Hay S, Were E, Renshaw M, Noor A, Ochola S, Olusanmi I, et al.: Forecasting, Warning and Detection of Malaria Epidemics: a case study. Lancet 2003, 361:1705-1706. 9370
• [21]Hay SI, Guerra CA, Gething PW, Patil AP, Tatem AJ, Noor AM, et al.: A world malaria map: Plasmodium falciparum endemicity in 2007. PLoS Med 2009, 6:e1000048.
• [22]Pascual M, Dobson AP, Bouma MJ: Understanding malaria risk under variable temperatures. PNAS 2009, 106:1364-13646.
• [23]Checchi F, Cox J, Balkan S, Tamrat A, Priotto G, Alberti KP, Guthmann JP: Malaria epidemics and interventions, Kenya, Burundi, southern Sudan, and Ethiopia, 1999–2004. Emerg Infect Dis 2006, 12:1477-1485.
• [24]Protopopoff N, Van Herp M, Maes P, Reid T, Baza D, D'Alessandro U, et al.: Vector control in a malaria epidemic occurring within a complex emergency situation in Burundi: a case study. Malar J 2007, 6:93. BioMed Central Full Text
• [25]Roll Back Malaria (RBM): Global strategic plan 2005–2015. RBM Partnership Secretariat, Geneva, Switzerland; 2005.
• [26]Hawley WA, Phillips-Howard PA, Ter Kuile FO, Terlouw DJ, Vulule JM, Ombok M, Nahlen BL, Gimnig JE, Kariuki SK, Kolczak MS, Hightower AW: Community-wide effects of permethrin-treated bed nets on child mortality and malaria morbidity in western Kenya. Am J Trop Med Hyg 2003, 68(Suppl 4):121-127.
• [27]Noor AM, Amin AA, Akhwale WS, Snow RW: Increasing coverage and decreasing inequity in insecticide-treated bed net use among rural Kenyan children. PLoS Med 2007, 4:e255.
• [28]Okiro EA, Hay SI, Gikandi PW, Sharif SK, Noor AM, Peshu N, et al.: The decline in paediatric malaria admissions on the coast of Kenya. Malar J 2007, 6:151. BioMed Central Full Text
• [29]Russell TL, Govella NJ, Azizi S, Drakeley CJ, Kachur SP, Killeen GF: Increased proportions of outdoor feeding among residual malaria vector populations following increased use of ITNs in rural Tanzania. Malar J 2011, 10:80. BioMed Central Full Text
• [30]Reddy MR, Overgaard HJ, Abaga S, Reddy VP, Caccone A, Kiszewski A, Slotman : Outdoor host seeking behavious of Anopheles gambiae mosquitoes following initiation of malaria vector control on Bioko Island. Equatorial Guinea. Malar J 2011, 10:184.
• [31]MalERA Consultative Group on Vector Control: A Research Agenda for Malaria Eradication: Vector Control. PLoS Med 2011, 8:e1000401.
• [32]Fillinger U, Lindsay SW: Larval Source Management for malaria control in Africa: myths and reality. Malar J 2011, 10:353. BioMed Central Full Text
• [33]Fillinger U, Lindsay SW: Suppression of exposure to malaria vectors by an order of magnitude using microbial larvicides in rural Kenya. Trop Med Int Health 2006, 11:1629-1642.
• [34]Fillinger U, Ndenga B, Githeko A, Lindsay SW: Integrated malaria vector control with microbial larvicides and insecticide treated nets in the western Kenyan highlands: a controlled trial. Bull World Health Organ 2009, 87:655-665.
• [35]Geissbuhler Y, Kannady K, Chaki PP, Emidi B, Govella NJ, Mayagaya V, et al.: Microbial larvicide application by a large-scale, community-based program reduces malaria infection prevalence in urban Dar es Salaam, Tanzania. PLoS One 2009, 4:e5107.
• [36]Majambere S, Lindsay SW, Green C, Kandeh B, Fillinger U: Microbial larvicides for malaria control in The Gambia. Malar J 2007, 6:76. BioMed Central Full Text
• [37]Fillinger U, Knols BG, Becker N: Efficacy and efficiency of new Bacillus thuringiensis var israelensis and Bacillus sphaericus formulations against Afrotropical anophelines in Western Kenya. Trop Med Int Health 2003, 8:37-47.
• [38]Imbahale SS, Mweresa C, Takken W, Mukabana WR: Development of environmental tools for anopheline larval control. Parasit Vectors 2011, 4:130. BioMed Central Full Text
• [39]Walker K, Lynch M: Contributions of Anopheles larval control to malaria suppression in tropical Africa: review of achievements and potential. Med Vet Entomol 2007, 21:2-21.
• [40]Service MW: Mosquito Ecology: Field Sampling Methods. Elsevier Applied Science, London; 1993.
• [41]Gillies MT, Coetzee M: A supplement to the Anophelinae of Africa South of the Sahara. The South African Institute for Medical Research, Johannesburg; 1987.
• [42]World Health Organization: Use of fish for mosquito control. WHO-EM/MAL/289/E/G Regional Office for the Eastern Mediterranean, Cairo; 2003.
• [43]Howard AF, Zhou G, Omlin FX: Malaria mosquito control using edible fish in western Kenya: preliminary findings of a controlled study. BMC Public Health 2007, 7:199. BioMed Central Full Text
• [44]Wamae PM, Githeko AK, Menya MD, Takken W: Shading by Napier grass reduces Malaria vector larvae in Natural habitats in Western Kenya highlands. Ecohealth 2010.
• [45]De Castro MC, Yamagata Y, Mtasiwa D, Tanner M, Utzinger J, Keiser J, et al.: Integrated urban malaria control: A case study in Dar Es Salaam, Tanzania. Am J Trop Med Hyg 2004, 71(2):103-117.
• [46]Kitron U, Spielman A: Suppression of transmission of malaria through source reduction: antianopheline measures applied in Israel, the United States, and Italy. Rev Infect Dis 1989, 11:391-406.
• [47]Utzinger J, Tozan Y, Singer BH: Efficacy and cost-effectiveness of environmental management for malaria control. Trop Med Int Health 2001, 6:677-687.
• [48]Killeen GF, Fillinger U, Knols BG: Advantages of larval control for African malaria vectors: low mobility and behavioural responsiveness of immature mosquito stages allow high effective coverage. Malar J 2002, 1:8. BioMed Central Full Text
• [49]Imbahale SS, Fillinger U, Githeko A, Mukabana WR, Takken W: An exploratory survey of malaria prevalence and people’s knowledge, attitudes and practices of mosquito larval source management for malaria control in western Kenya. Acta Trop 2010, 115:248-256.
• [50]Van den Berg H, Knols BG: The Farmer Field School: a method for enhancing the role of rural communities in malaria control? Malar J 2006, 5:3. BioMed Central Full Text
• [51]den Berg V, Takken : A framework for decision-making in integrated vector management to prevent disease. Trop Med Int Health 2007, 12:1230-1238.