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Investigating knockdown resistance (kdr) mechanism against pyrethroids/DDT in the malaria vector Anopheles funestus across Africa

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Irving, Helen and Wondji, Charles ORCID: https://orcid.org/0000-0003-0791-3673 (2017) 'Investigating knockdown resistance (kdr) mechanism against pyrethroids/DDT in the malaria vector Anopheles funestus across Africa'. BMC Genetics, Vol 17, e76.

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Abstract

Background

Understanding the molecular basis of insecticide resistance is key to improve the surveillance and monitoring of malaria vector populations under control. In the major malaria vector Anopheles funestus, little is currently known about the role of the knockdown resistance (kdr) mechanism. Here, we investigated the presence and contribution of knockdown resistance (kdr) to pyrethroids/DDT resistance observed in Anopheles funestus across Africa.

Results

Pyrosequencing genotyping and sequencing of the voltage gated sodium channel (VGSC) gene did not detect the common L1014F mutation in field collected An. funestus across Africa. Amplification and cloning of the full-length of the sodium channel gene in pyrethroid resistant mosquitoes revealed evidences of alternative splicing events with three transcripts of 2092, 2061 and 2117 amino acids (93% average similarity to An. gambiae). Several amino acid changes were detected close to the domain II of the protein such as L928R, F938 W, I939S, L802S and T1008 M. However, all these mutations are found at low frequency and their role in pyrethroid resistance could not be established. The presence of the exclusive alternative splicing at exon 19 was not associated with resistance phenotype. Analysis of patterns of genetic diversity of the VGSC gene revealed a high polymorphism level of this gene across Africa with no evidence of directional selection suggesting a limited role for knockdown resistance in pyrethroid resistance in An. funestus. Patterns of genetic differentiation correlate with previous observations of the existence of barriers to gene flow Africa-wide with southern population significantly differentiated from other regions.

Conclusion

Despite an apparent limited role of knockdown resistance in An. funestus, it is necessary to continue to monitor the contribution of the mutations detected here as increasing selection from insecticide-based interventions may change the dynamic in field populations as previously observed in other vectors.

Item Type: Article
Subjects: QX Parasitology > Insects. Other Parasites > QX 510 Mosquitoes
QX Parasitology > Insects. Other Parasites > QX 515 Anopheles
QX Parasitology > Insects. Other Parasites > QX 600 Insect control. Tick control
WA Public Health > Preventive Medicine > WA 240 Disinfection. Disinfestation. Pesticides (including diseases caused by)
WA Public Health > WA 30 Socioeconomic factors in public health (General)
WA Public Health > Health Problems of Special Population Groups > WA 395 Health in developing countries
WC Communicable Diseases > Tropical and Parasitic Diseases > WC 750 Malaria
WC Communicable Diseases > Tropical and Parasitic Diseases > WC 765 Prevention and control
Faculty: Department: Biological Sciences > Vector Biology Department
Digital Object Identifer (DOI): https://doi.org/10.1186/s12863-017-0539-x
Depositing User: Stacy Murtagh
Date Deposited: 31 Aug 2017 09:32
Last Modified: 12 Oct 2017 15:44
URI: http://archive.lstmed.ac.uk/id/eprint/7520

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