▁effective ▁as ▁using ▁insect ic ide ▁treated ▁n ets ▁( IT N ) s , ▁though ▁IT N s ▁may ▁be ▁a ▁more ▁effective ▁at ▁reducing ▁mor bid ity ▁in ▁some ▁situations . ▁ ▁F ew ▁studies ▁have ▁directly ▁compared ▁the ▁cost ▁effect iveness ▁of ▁I RS ▁directly ▁with ▁other ▁methods ▁of ▁mal aria ▁control . ▁A ▁study ▁from ▁ 2 0 0 8 ▁ass essed ▁the ▁cost ▁effect iveness ▁of ▁seven ▁African ▁anti - mal aria ▁campaign s : ▁two ▁I RS ▁campaign s ▁and ▁five ▁insect ic ide ▁treated ▁bed net ▁( IT N ) ▁distribution ▁campaign s . ▁The ▁authors ▁found ▁that ▁on ▁a ▁cost - per - child - de ath - a vert ed ▁basis , ▁all ▁were ▁about ▁the ▁same , ▁but ▁the ▁IT N ▁campaign s ▁were ▁slightly ▁more ▁cost ▁effective . ▁ ▁With ▁regard ▁to ▁the ▁cost ▁effect iveness ▁of ▁various ▁p estic ides ▁vis - a - vis ▁each ▁other ▁for ▁I RS , ▁histor ically ▁D DT ▁has ▁been ▁considered ▁the ▁most ▁cost ▁effective , ▁mainly ▁because ▁it ▁last s ▁longer ▁than ▁alternatives ▁and ▁therefore ▁dwell ings ▁can ▁be ▁sp rayed ▁less ▁frequently . ▁But ▁actual ▁studies ▁on ▁cost ▁effect iveness ▁are ▁lack ing , ▁and ▁none ▁have ▁taken ▁into ▁account ▁the ▁ad verse ▁health ▁and ▁environmental ▁effects ▁of ▁D DT ▁or ▁its ▁alternatives . ▁The ▁United ▁Nations ▁Environment ▁Program me ▁( UN EP ) ▁concluded ▁in ▁ 2 0 0 8 ▁that ▁" IR S ▁with ▁D DT ▁remains ▁afford able ▁and