The efficacy of long-lasting nets with declining physical integrity may be compromised in areas with high levels of pyrethroid resistance

Malaria Journal

Research

Andrew K Githeko¹  John Vulule¹  Collins Ouma²  Guiyun Yan³  Edward D Walker⁴  John E Gimnig⁵  Nabie M Bayoh⁶  Maurice O Ombok⁶  Bernard O Abongo⁶  Eric O Ochomo⁷ 

[1] Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya;Department of Biomedical Science and Technology, School of Public Health and Community Development, Maseno University, Maseno, Kenya;Department of Ecology & Evolutionary Biology, School of Biological Sciences, University of California, Irvine, CA, USA;Department of Microbiology and molecular genetics, Michigan State University, East Lansing, MI, USA;Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA;KEMRI/CDC Research and Public Health Collaboration, PO Box 1578, 40100, Kisumu, Kenya;KEMRI/CDC Research and Public Health Collaboration, PO Box 1578, 40100, Kisumu, Kenya;Department of Biomedical Science and Technology, School of Public Health and Community Development, Maseno University, Maseno, Kenya;

关键词: Malaria;    Indoor Residual Spray;    Malaria Vector;    Insecticide Resistance;    Malaria Control Programme;   

DOI  :  10.1186/1475-2875-12-368

 received in 2013-08-23, accepted in 2013-10-23,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundLong-lasting insecticide-treated mosquito nets (LLINs) are a primary malaria prevention strategy in sub-Saharan Africa. However, emergence of insecticide resistance threatens the effectiveness of LLINs.MethodsCross-sectional surveys of LLINs were conducted in houses of seven and four villages in Gem and Bungoma Districts in western Kenya, respectively. Condition (number and area of holes in the nets), number and species of mosquitoes resting inside them, and insecticidal activity of nets were quantified. Mosquitoes collected inside nets were allowed to lay eggs and progeny tested for susceptibility to deltamethrin and permethrin, pyrethoids commonly deployed in LLINs in western Kenya.ResultsIn Gem, 83.3% of nets were less than three years old and 32.4% had at least one hole of any size; while in Bungoma, 92% were less than three years old and 48% had at least one hole. No anopheline and five Culex spp. mosquitoes were found resting inside nets in Gem regardless of the number and size of holes, while 552 Anopheles gambiae s.l., five Anopheles funestus s.l. and 137 Culex spp. were in nets in Bungoma. The number of mosquitoes resting inside nets increased with hole areas >50 cm in Bungoma. In WHO resistance assays, f1 offspring of samples collected in nets in Bungoma were 94 and 65% resistant to deltamethrin and permethrin, respectively. Nets from Bungoma retained strong activity against a susceptible laboratory strain, but not against f1 offspring of field-collected An. gambiae s.s. All An. gambiae s.s. samples collected in nets were homozygous for the kdr genotype L1014S.ConclusionsIn areas with pyrethroid resistant vectors, LLINs with modest hole areas permit mosquito entry and feeding, providing little protection against the vectors. LLIN formulations develop large holes within three years of use, diminishing their presupposed lifetime effectiveness.

【 授权许可】

CC BY   
© Ochomo et al.; licensee BioMed Central Ltd. 2013