ABSTRACT
Information on Culex mosquitoes (vectors of filarial worm and
viral encephalitis) from northern Nigeria is scanty, hindering evidence-based
control. Here, two Culex populations (Kano and Kaduna) were
characterized. Culex quinquefasciatus and Culex pipiens were
found breeding in sympatry, with some hybrid individuals identified. Larval
bioassays revealed high temephos resistance (LC50s = 1.34 mg/mL and
3.01 mg/mL for Kano and Kaduna, respectively). Larvae were more sensitive to α-cypermethrin (LC50s = 0.026
mg/mL and 0.067 mg/mL for Kano and Kaduna). WHO adult tube bioassays revealed
high pyrethroid and DDT resistance, with mortalities of 44.01% ± 6.79%, 35.83%
± 12.58%, 29.69% ± 9.97% and 52.47% ± 4.34% for permethrin, deltamethrin, α-cypermethrin and DDT, respectively.
Highest resistance was observed with bendiocarb (mortality = 13.58% ± 3.98%).
High resistance was obtained with fenitrothion and malathion (mortalities = 21%
± 4.76% and 56.47% ± 8.67%, respectively), while a full susceptibility was
observed with pirimiphos-methyl. Pre-exposure to piperonylbutoxide (PBO)
significantly recovered α-cypermethrin
susceptibility (mortality = 82% ± 5.16%, χ2 = 50.99, p < 0.0001), compared with the conventional bioassay (mortality =
32 ± 7.30). Mortalities of <20% were obtained in cone bioassays with
Yorkool, DuraNet and PermaNet3.0 (side panels) nets, suggesting a loss of
efficacy of conventional long-lasting insecticidal nets. However, mortalities
of 99% and 86% were obtained in Kano and Kaduna populations using the roof of
PermaNet3.0 (containing PBO and deltamethrin). Despite the high frequency of
the 1014F VGSC knockdown resistance mutation allele (0.90), no correlation was
observed between the 1014F kdr genotype and resistance phenotype.
Sequencing of fragments of the acetylcholinesterase-1 gene detected no
G119S mutation, in malathion-alive and malathion-dead females. These suggest a
preeminent role of metabolic resistance in these Culex populations.
Share and Cite:
A. Datti, J. , M. Mukhtar, M. , T. Usman, M. , I. Abba, B. , G. Kurfi, B. and S. Ibrahim, S. (2022) Evaluation of Efficacy of Insecticides and Long-Lasting Insecticidal Nets for Control of
Culex quinquefasciatus Say Populations from Northern Nigeria.
Advances in Entomology,
10, 186-203. doi:
10.4236/ae.2022.102014.