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Long Lasting Insecticidal Nets

Long Lasting Insecticide-Treated Nets

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Long Lasting Insecticidal Nets

Overview

Long lasting insecticidal nets (LLINs) are being promoted by WHO and Roll Back Malaria partners as a cost effective and sustainable method for protection against malaria. LLINs are nets treated in the factory with an insecticide incorporated into the net fabric which makes the insecticide last at least 20 washes in standard laboratory testing and three years of recommended use under field conditions. With LLINs therefore the time consuming method of retreating old nets is no longer necessary.

There are at present three LLINs recommended as eligible for public sector procurement by the WHO Pesticide Evaluation Scheme - Olyset Net®, which has 2% permethrin incorporated into the polyethylene fibres, PermaNet® which is treated with 55mg/m2 of deltamethrin to coat fibres and Interceptor®, which has a target dose of 200mg alpha-cypermethrin per square metre polyester netting and received a preliminary recommendation pending phase 3 data.  Olyset Net® has wider mesh size (4mm x 4mm) than the PermaNet®.

At present many ITNs and LLINs look physically very similar. The LLINs need to be easily distinguishable from normal ITNs. This is particularly relevant in areas with high levels of net re-treatment, to make sure only ITNs receive retreatment.

Until recently many ITNs were distributed but net retreatment has often not been successful. The use of LLINs ensures long-term protection against mosquitoes.  Until LLIN coverage is higher, however, there is a need to organise treatment of untreated nets and retreatment of conventional ITNs.  The use of K-O TAB 1-2-3® to retreat nets is potentially useful, as it can give protection for longer than standard insecticide treatments (up to 15 standardised washes in trials so far).

Key Points:

Long Lasting Insecticidal Nets: The Malaria Consortium is involved in several projects concerning the delivery, financing, and evaluating the cost effectiveness of LLINs, including Developing a Sustainable Markets for Nets in Mozambique [Mozambique programme], AFFORD programme [AFFORD], a study in Northern Uganda IDP Camps (see below and [Link to Pregnancy and Nets in N Uganda]), and a study to look at a new insecticide to retreat nets, that will make the nets longer lasting than conventional ITNs [ K-O TAB 1-2-3 Programme].

References:

* Dabire, R.K., Diabate, A., Baldet, T., Pare-Toe, L., Guiguemde, R.T., Ouedraogo, J.B. & Skovmand, O. (2006) Personal protection of long lasting insecticide-treated nets in areas of Anopheles gambiae s.s. resistance to pyrethroids. Malaria Journal 5: 12.
Tami, A., Mubyazi, G., Talbert, A., Mshinda, H., Duchon, S. & Lengeler, C. (2004) Evaluation of OlysetTM insecticide-treated nets distributed seven years previously in Tanzania . Malaria Journal 3: 19.
* World Health Organization Communicable Disease Control Prevention and Eradication/WHO Pesticide Evaluation Scheme..Report on the WHOPES Working Group Meeting (2001): Review of Olyset Bifenthrin 10% WP.
* Kilian AHD., Byamukama W., Rubaale T., Hougard JM., Duchon S., Pigeon O., Gardiner E., Chau MK., Von Sonneburg F., Korte R.(2002) A Double Blind Randomized Comparison of the Field performance of Long-lasting and Conventional Insecticide Mosquito Nets in Western Uganda. GTZ publication
* RBM (2004) Fifth Update on Long Lasting Insecticidal Nets: Current Status and Programmatic Issues - permanent 2.0 A New LLIN Recommended by WHO. Roll Back Malaria
* RBM ( 2005) Procuring Long Lasting Insecticide Nets (LLINs) or Bundled-Insecticide Treated (ITNs)Roll Back Malaria
* Guillet PF (2003). Long Lasting Insecticide Nets: Current status and Programmatic Issues WHO Geneva.
* RBM (2003) Fourth Update on Long Lasting Insecticidal Nets: Current Status and Programmtic Issues Roll Back Malaria
* WHO (2007) Report of the Tenth WHOPES Working Group Meeting, Review of: spinosad 0.5% GR and 12% SC, lambda-cyhalothrin 10% CS, K-O TAB 1-2-3® and Interceptor® WHO/CDS/NTD/WHOPES/2007.1 

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