Insecticide resistance status of Culex species in urban areas in Ghana and efficacy of long lasting nets against them

Background Current strategic plans for malaria control in Ghana
include the attainment of 80% of the general population sleeping
under insecticide treated materials (ITM) by 2015. This coverage
may not be attained if there is non-compliance in the use of bed
nets. Failure of ITM to protect users from nuisance mosquitoes,
particularly Culex mosquitoes has been cited as one of the major
threats to the sustained use of ITM. A nationwide survey was
therefore carried out to determine insecticide resistance status of
Culex species and efficacy of ITM against them. Methods and
materials Mosquito larvae were sampled from various land use and
ecological settings and at different seasons. These were reared to
adults and used for the various tests. In adults, insecticide
susceptibility tests to eight insecticides as well as cone and
tunnel bioassays were performed. Biochemical and molecular analyses
were also conducted to determine the resistance mechanisms in the
study populations. Results Culex quinquefasciatus and C. decens
were the Culex species that were identified in the study area. DDT
and deltamethrin resistances were evident across the country. A
strong relationship between resistance status and urban size was
observed in the study population (Pearson χ2 =48.2; df = 1;
P