Comparison of the efficacy of long-lasting insecticidal nets PermaNet® 2.0 and Olyset® against Anopheles albimanus

Malaria is considered to be the most prevalent vectorborne disease worldwide. For its prevention, it is necessary to have an appropriate and timely care program for patients and successful integrated and selective control of the vector species (Rafinejad et al. 2008). This control in highly endemic countries relies largely on one of two main methods: insecticide-treated (mosquito) nets (ITNs) and indoor residual (house) spraying. Both methods are known to be highly effective and current evidence suggests that they are very similar in their relative impact on malaria incidence (Yukich et al. 2008). Given the increasing availability of resources for malaria control, the Roll Back Malaria Partnership set an ambitious target for 2010 of 80% protection of high-risk groups by a “locally appropriate” vector control measure (RBM 2005). As a consequence of this decision, ITNs are being implemented as part of national malaria control programs around the world (Lindblade et al. 2005). ITNs lead to a reduction of human-vector contact and provide a physical barrier; the scale-up will not only protect users, but also non-users through insecticidal and/or repellent effects gained with high coverage levels that benefit the whole community (Rafinejad et al. 2008, Gu & Novak 2009). There are two categories of ITNs: conventionally treated nets and long-lasting insecticidal nets (LLINs). A conventionally treated net is a mosquito net that has been treated by dipping in a World Health Organization (WHO) recommended insecticide. To ensure its continued insecticidal effect, the net should be re-treated regularly, usually after about three washes or at least once a year. A LLIN is a factory-treated mosquito net made with netting material that has insecticide incorporated within or bound around the fibres. The net must retain its effective biological activity without re-treatment for at least 20 WHO standard washes under laboratory conditions and three years of recommended use under field conditions (WHO 2005). Pyrethroids are the only class of insecticides that are currently recommended for use on mosquito nets. Treated nets should be non-toxic for children and non-irritant when in contact with exposed skin. The insecticides recommended by the WHO Pesticide Evaluation Scheme (WHOPES) are alpha-cypermethrin (10%), cyfluthrin (5%), deltamethrin (1-25%), etofenprox (10%), lambdacyhalothrin (2.5%) and permethrin (10%) (Zaim et al. 2000, Nagera & Zaim 2004). Three LLINs have been fully recommended by the WHO and are now commercially available: Olyset®, PermaNet® 2.0 and Yorkool LLIN (WHO 2010). An additional six LLINs have an interim recommendation from the WHOPES for the prevention of malaria: DawaPlus® 2.0, PermaNet® 2.5, PermaNet® 3.0, Netprotect®, Duranet® and Interceptor®. Data on the efficacy of the interim recommended nets remains limited (Banek et al. 2010, WHO 2010). Financial support: Vestergaard Frandsen + Corresponding author: [email protected] Received 27 February 2011 Accepted 14 July 2011 Comparison of the efficacy of long-lasting insecticidal nets PermaNet® 2.0 and Olyset® against Anopheles albimanus under laboratory conditions