A longitudinal study of the durability of long-lasting insecticidal nets in Zambia

Malaria Journal

Research

Cecilia Katebe-Sakala¹  Jodi Vanden Eng²  Carla T. Mapp³  Stephen C. Smith³  Robert Wirtz³  Kathrine R. Tan⁴  Allen S. Craig⁵  Jane Coleman⁶  Tiffany K. Parris⁷  Barbara Smith⁸  Ashley Kowal⁹  Casey Kean^1,10  Mulakwa Kamuliwo^1,11  Busiku Hamainza^1,11 

[1] Bayer (Pty) Ltd, Isando, South Africa;Center for Global Health, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA;Center for Global Health, Entomology Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA;Center for Global Health, Malaria Branch, Centers for Disease Control and Prevention, 1600 Clifton Rd. MS A6, 30333, Atlanta, GA, USA;Center for Global Health, Polio Eradication Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA;Jhpiego, an affiliate of Johns Hopkins University, Washington, DC, USA;National Center for Enteric, Zoonotic, and Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA;Peace Corps, West Coast Region, San Francisco, CA, USA;Society for Family Health, Lusaka, Zambia;Success Academy Charter Schools, Brooklyn, NY, USA;Zambia National Malaria Control Centre, Lusaka, Zambia;

关键词: Long-lasting insecticidal nets;    Durability;    Attrition;   

DOI  :  10.1186/s12936-016-1154-4

 received in 2015-11-14, accepted in 2016-02-09,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundA key goal of malaria control is to achieve universal access to, and use of, long-lasting insecticidal nets (LLINs) among people at risk for malaria. Quantifying the number of LLINs needed to achieve and maintain universal coverage requires knowing when nets need replacement. Longitudinal studies have observed physical deterioration in LLINs well before the assumed net lifespan of 3 years. The objective of this study was to describe attrition, physical integrity and insecticide persistence of LLINs over time to assist with better quantification of nets needing replacement.Methods999 LLINs distributed in 2011 in two highly endemic provinces in Zambia were randomly selected, and were enrolled at 12 months old. LLINs were followed every 6 months up to 30 months of age. Holes were counted and measured (finger, fist, and head method) and a proportional hole index (pHI) was calculated. Households were surveyed about net care and repair and if applicable, reasons for attrition. Functional survival was defined as nets with a pHI <643 and present for follow-up. At 12 and 24 months of age, 74 LLINs were randomly selected for examination of insecticidal activity and content using bioassay and chemical analysis methods previously described by the World Health Organization (WHO).ResultsA total of 999 LLINs were enrolled; 505 deltamethrin-treated polyester nets and 494 permethrin-treated polyethylene nets. With 74 used to examine insecticide activity, 925 were available for full follow-up. At 30 months, 325 (33 %) LLINs remained. Net attrition was primarily due to disposal (29 %). Presence of repairs and use over a reed mat were significantly associated with larger pHIs. By 30 months, only 56 % of remaining nets met criteria for functional survival. A shorter functional survival was associated with having been washed. At 24 months, nets had reduced insecticidal activity (57 % met WHO minimal criteria) and content (5 % met WHO target insecticide content).ConclusionsThe median functional survival time for LLINs observed the study was 2.5–3 years and insecticide activity and content were markedly decreased by 2 years. A better measure of net survival incorporating insecticidal field effectiveness, net physical integrity, and attrition is needed.

【 授权许可】

CC BY   
© Tan et al. 2016