Fine-scale spatial and temporal variations in insecticide resistance in Culex pipiens complex mosquitoes in rural south-eastern Tanzania

Table 5 Mean % mortality recorded 24 hours after exposure to 4% DDT, with and without the synergist, diethyl maleate (DEM). The mosquitoes tested were 3- to 5-day-old adult Culex mosquitoes reared from wild collected larvae from Minepa and Mavimba wards in Ulanga District, Tanzania, in 2015 and 2016

Treatment	No. of replicates	Sample size	Mean % mortality (95% CI)
Treatment	No. of replicates	Sample size	Mavimba (8.312° S, 36.677° E)	Minepa (8.271° S, 36.677° E)
Environmental control	4	80	0	0
Solvent control	4	80	0	0
20% DEM only	4	80	0	0
20% DEM and 4% DDT	4	80	82.5 (67.3–97.7)^a	90.0 (83.5–96.5)^a
4% DDT only	4	80	48.8 (38.7–58.8)^b	95.0 (88.5–101.5)^a

Notes: Morphological identification of the Culex mosquitoes revealed 94% were Cx.pipiens complex. Of these, PCR assays revealed that 81% were Cx. quinquefasciatus, 2% were Cx. pipiens pipiens and 3% were hybrids of the two species. About 14% of the specimens were non-amplified. Environmental control refers to a control where mosquitoes are exposed to non-treated papers, and is used to assess any contamination in the test environment or during the procedures
^a,bThe letters a and b signify statistically significant differences between % mortalities obtained in tests with or without the synergists

ISSN: 1756-3305