Presence of L1014F Knockdown-Resistance Mutation in Anopheles gambiae s.s. From São Tomé and Príncipe.

Hongying Zhang,Shaoqing Zheng,Qin Xu,Fei Tuo,D’Almeida Herodes Rompão,Carlos Alberto Bandeira,Wenfeng Guo,Bo Huang,Yueming Yuan,Ruixiang Tan,Zhibin Wu,Mingqiang Li,Qi Wang,Jianping Song,Changsheng Deng

doi:10.3389/fcimb.2021.633905

Abstract

Malaria, one of the most serious parasitic diseases, kills thousands of people every year, especially in Africa. São Tomé and Príncipe are known to have stable transmission of malaria. Indoor residual spraying (IRS) of insecticides and long-lasting insecticidal nets (LLIN) are considered as an effective malaria control interventions in these places. The resistance status of Anopheles gambiae s.s. from Agua Grande, Caue, and Lemba of São Tomé and Príncipe to insecticides, such as dichlorodiphenyltrichloroethane (DDT) (4.0%), deltamethrin (0.05%), permethrin (0.75%), fenitrothion (1.0%), and malathion (5.0%), were tested according to the WHO standard protocol. DNA extraction, species identification, as well as kdr and ace-1R genotyping were done with the surviving and dead mosquitoes post testing. They showed resistance to cypermethrin with mortality rates ranging from 89.06% to 89.66%. Mosquitoes collected from Agua Grande, Caue, and Lemba displayed resistance to DDT and fenitrothion with mortality rates higher than 90%. No other species were detected in these study localities other than Anopheles gambiae s.s. The frequency of L1014F was high in the three investigated sites, which was detected for the first time in São Tomé and Príncipe. No ace-1R mutation was detected in all investigated sites. The high frequency of L1014F showed that kdr L1014F mutation might be related to insecticide resistance to Anopheles gambiae s.s. populations from São Tomé and Príncipe. Insecticide resistance status is alarming and, therefore, future malaria vector management should be seriously considered by the government of São Tomé and Príncipe.

Highlights

Malaria, one of the most deadly parasitic diseases, has claimed thousands of people every year worldwide, especially in Africa
The study showed that the levels of insecticide resistance in Anopheles gambiae s.s. were high in São Tomé and Prıń cipe with high allelic frequencies
Kdr allele frequencies were high at Agua Grande and Lemba, and for the first time, the high frequency kdr mutation of L1014F was detected in São Tomé and Prıń cipe

Summary

Introduction

One of the most deadly parasitic diseases, has claimed thousands of people every year worldwide, especially in Africa. Anopheles gambiae s.s. was the only malaria vector found in São Tomé and Prıń cipe (Pinto et al, 2000). In São Tomé and Prıń cipe, malaria control strategies, such as long-lasting insecticidal nets (LLINs), indoor residual spraying (IRS) of insecticides, are carried out. Cypermethrin was the most recommended compounds for IRS and LLINs in these late years as it is a fast-acting and low-toxicity insecticide (Graham et al, 2005). IRS of insecticides was carried out for the 16th time in October 2019 in São Tomé and Prıń cipe. The evidence of malaria reduction coupled with IRS was reported in São Tomé and Prıń cipe (Hagmann et al, 2003; Lee et al, 2010b)

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Conclusion