Resistance to DDT in an urban setting: common mechanisms implicated in both M and S forms of Anopheles gambiae in the city of Yaoundé Cameroon.

Fossog Tene, Billy, Poupardin, Rodolphe, Costantini, Carlo, Awono-Ambene, Parfait, Wondji, Charles ORCID: https://orcid.org/0000-0003-0791-3673, Ranson, Hilary ORCID: https://orcid.org/0000-0003-2332-8247 and Nkondjio, Christophe (2013) 'Resistance to DDT in an urban setting: common mechanisms implicated in both M and S forms of Anopheles gambiae in the city of Yaoundé Cameroon.'. PLoS ONE, Vol 8, Issue 4, e61408.

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Abstract

BACKGROUND

In the city of Yaoundé in Cameroon malaria is predominately transmitted by the M and S molecular forms of Anopheles gambiae and both are resistant to the pyrethroid insecticides and DDT. Mutations in the target site of these insecticides, present at a high frequency in malaria vectors in this city, contribute to this resistance profile. To identify additional resistance mechanisms, the expression profile of multiple DDT-resistant field populations of M and S molecular forms was compared to laboratory-susceptible populations.

METHODOLOGY/PRINCIPAL FINDINGS

The prevalence of DDT resistance was highest in the S form population originating from the cultivated site of Nkolondom (mortality after WHO bioassay = 4%). A high prevalence of DDT resistance was also found in two urban M form populations, Messa from a pristine unpolluted environment (DDT mortality = 54%), and Gare, where the breeding sites are heavily polluted with organic matter (DDT mortality = 38%). Microarray analysis showed that several transcripts coding for detoxification enzymes (P450s, GSTs and UDPGTs) and ABC transporters were upregulated in the three populations. Despite the presence of multiple detoxification genes over expressed in the DDT-resistant subset of these field populations, only three were commonly over expressed in resistant populations from all three environments. Two of these genes, CYP6M2 and GSTD1-6, encode enzymes that have been previously shown to metabolize DDT.

CONCLUSION/SIGNIFICANCE
Analogous to target site resistance, genes involved in metabolic resistance to DDT are also shared between the M and S forms of An gambiae. Alternative explanations for this occurrence are explored.

Item Type:	Article
Subjects:	QX Parasitology > Insects. Other Parasites > QX 515 Anopheles QX Parasitology > Insects. Other Parasites > QX 600 Insect control. Tick control 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/10.1371/journal.pone.0061408
Depositing User:	Samantha Sheldrake
Date Deposited:	05 Jul 2013 10:00
Last Modified:	13 Sep 2019 15:47
URI:	https://archive.lstmed.ac.uk/id/eprint/3437

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