In 2006, the World Health Organization encouraged a scale-up in IRS methods for vector borne disease control and concurrently endorsed DDT for this technique (WHO 2006; Kolaczinski et al. 2007). Out of 106 malaria-burdened countries, 51 currently report the use of IRS and 13 of these countries report use of DDT—an increase from 44 and 12, respectively, in 2009 (WHO 2009; WHO 2011). There are 11 other chemicals currently recommended by WHO for use in IRS, including bendiocarb, malathion, lambda-cyhalothrin, and alphacypermethrin (WHO 2006). Current WHO policy advocates rotation of IRS chemicals, and the reduction in use of pyrethroids so as effectively manage insecticide resistance (WHO 2011).
