High Level of Pyrethroid Resistance in an Anopheles funestus Population of the Chokwe District in Mozambique

Cuamba, Nelson, Morgan, John, Irving, Helen, Steven, Andrew and Wondji, Charles ORCID: https://orcid.org/0000-0003-0791-3673 (2010) 'High Level of Pyrethroid Resistance in an Anopheles funestus Population of the Chokwe District in Mozambique'. PLoS ONE, Vol 5, Issue 6, e11010.

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Abstract

Background

Although Anopheles funestus is difficult to rear, it is crucial to analyse field populations of this malaria vector in order to successfully characterise mechanisms of insecticide resistance observed in this species in Africa. In this study we carried out a large-scale field collection and rearing of An. funestus from Mozambique in order to analyse its susceptibility status to insecticides and to broadly characterise the main resistance mechanisms involved in natural populations.

Methodology/Principal Findings

3,000 F1 adults were obtained through larval rearing. WHO susceptibility assays indicated a very high resistance to pyrethroids with no mortality recorded after 1h30min exposure and less than 50% mortality at 3h30min. Resistance to the carbamate, bendiocarb was also noted, with 70% mortality after 1h exposure. In contrast, no DDT resistance was observed, indicating that no kdr-type resistance was involved. The sequencing of the acetylcholinesterase gene indicated the absence of the G119S and F455W mutations associated with carbamate and organophosphate resistance. This could explain the absence of malathion resistance in this population. Both biochemical assays and quantitative PCR implicated up-regulated P450 genes in pyrethroid resistance, with GSTs playing a secondary role. The carbamate resistance observed in this population is probably conferred by the observed altered AChE with
esterases also involved.

Conclusion/Significance

The high level of pyrethroid resistance in this population despite the cessation of pyrethroid use for IRS in 1999 is a serious concern for resistance management strategies such as rotational use of insecticides. As DDT has now been re-introduced for IRS, susceptibility to DDT needs to be closely monitored to prevent the appearance and spread of resistance to this insecticide.

Item Type:	Article
Subjects:	QW Microbiology and Immunology > Immune Responses > QW 700 Infection. Mechanisms of infection and resistance. WC Communicable Diseases > Tropical and Parasitic Diseases > WC 680 Tropical diseases (General) WC Communicable Diseases > Tropical and Parasitic Diseases > WC 750 Malaria QX Parasitology > Insects. Other Parasites > QX 650 Insect vectors QX Parasitology > Insects. Other Parasites > QX 515 Anopheles WB Practice of Medicine > Medical Climatology > WB 710 Diseases of geographic areas WA Public Health > Preventive Medicine > WA 110 Prevention and control of communicable diseases. Transmission of infectious diseases WA Public Health > Preventive Medicine > WA 240 Disinfection. Disinfestation. Pesticides (including diseases caused by) WC Communicable Diseases > Tropical and Parasitic Diseases > WC 765 Prevention and control QX Parasitology > Insects. Other Parasites > QX 600 Insect control. Tick control QX Parasitology > Insects. Other Parasites > QX 510 Mosquitoes WC Communicable Diseases > Tropical and Parasitic Diseases > WC 695 Parasitic diseases (General)
Faculty: Department:	Groups (2002 - 2012) > Vector Group
Digital Object Identifer (DOI):	https://doi.org/10.1371/journal.pone.0011010
Depositing User:	Users 183 not found.
Date Deposited:	10 Jun 2010 17:46
Last Modified:	13 Sep 2019 15:47
URI:	https://archive.lstmed.ac.uk/id/eprint/1010

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