Investigation on The Level of Insecticide Resistance to Malaria Vectors in Ruangwa District Lindi Region Tanzania

Abstract

High malaria prevalence remains a major problem in Ruangwa District, despite the high coverage rates of malaria control interventions. The objective of this study was to assess the level of insecticide resistance in malaria vectors in southern, Tanzania. The study was conducted in three villages of Likangara, Nandagara and Chienjere. Resistance level to insecticides in An. gambiae s.l was evaluated using a standard WHO Susceptibility Test Kit. These mosquitoes were reared from larvae collected in varoius breeding sites in a major rice, vegetable and leguminous plant cultivation area in which pesticides use is intensive. Each test was run in four replicates of 25 adult non-blood fed female Anopheles gambiae s.l mosquitoes per tube. In total, 100 specimens were exposed for standard concentration of 1% fenitrothion, 0.1% bendiocarb, 0.75% permethrin and 0.05% deltamethrin  using WHO susceptibility test kit.  The number of knocked down mosquitoes were recorded at 10,15,20,30,50  and 60 min  and mortality rates were determined after 24 hours and results were classified according to WHO guidelines, as susceptible (97-100%), possible resistance (90%-98%) and resistance (<90%). The results indicate suggestive levels of mosquitoes resistance to Bendiocarb at (75%), possible resitance levels of Deltamethrin  at (95%), Permethrin at (97%) and Fenitrothion at (96%) (p < 0.05). This implies that there is reduced effectiveness of insecticides used in vector control interventions in   the   district.   Superior   insecticides   should   made   available and introduced in order to promote the sustainable management of malaria vectors and elimination malaria transmission in the district.