TY - JOUR
T1 - Multiple insecticide resistance in the major malaria vector Anopheles funestus in southern Ghana: implications for malaria control
AU - Riveron, Jacob M.
AU - Osae, Michael
AU - Egyir-Yawson, Alexander
AU - Irving, Helen
AU - Ibrahim, Sulaiman S.
AU - Wondji, Charles
PY - 2016/9/15
Y1 - 2016/9/15
N2 - BackgroundUnderstanding the dynamics of insecticide resistance in African malaria vectors is crucial for successful implementation of resistance management strategies in the continent. This study reports a high and multiple insecticide resistance in Anopheles funestus from southern Ghana which could compromise the Malaria Operational Plan in this country, if not tackled. Adult Anopheles mosquitoes were collected in Obuasi and Adawukwa, in southern Ghana. Plasmodium infection rates, susceptibility to the main insecticides used in public health and the molecular basis of insecticide resistance were established.ResultsAn. funestus (sensu stricto) (s.s.) was the predominant mosquito species found resting inside the houses in Obuasi, while at Adawukwa it was found together with An. coluzzii. Parasite rates were high in An. funestus (s.s.) populations from both localities, with Plasmodium infection rates greater than 12.5 %. Both, An. funestus (s.s.) and An. coluzzii, from the two sites exhibited high resistance to the insecticide from various classes including the pyrethroids, carbamates and DDT, but remained fully susceptible to the organophosphates. A preliminary characterization of the underlying molecular mechanisms of resistance in An. funestus (s.s.) populations from both sites revealed that CYP6P9a, CYP6P9b, CYP6M7 and GSTe2 genes are upregulated, markedly higher in Obuasi (between 3.35 and 1.83 times) than in Adawukwa population. The frequency of L119F-GSTe2 and A296S-RDL resistance markers were also higher in Obuasi (42.5 and 68.95 % higher), compared with An. funestus (s.s.) populations from Adawukwa. These findings suggest that the similar resistance pattern observed in both An. funestus (s.s.) populations are driven by different mechanisms.ConclusionsResistance to multiple insecticides in public health use is present in malaria vectors from Ghana with major resistance genes already operating in the field. This should be taken into consideration in the design of resistance management strategies to avoid operational failure.
AB - BackgroundUnderstanding the dynamics of insecticide resistance in African malaria vectors is crucial for successful implementation of resistance management strategies in the continent. This study reports a high and multiple insecticide resistance in Anopheles funestus from southern Ghana which could compromise the Malaria Operational Plan in this country, if not tackled. Adult Anopheles mosquitoes were collected in Obuasi and Adawukwa, in southern Ghana. Plasmodium infection rates, susceptibility to the main insecticides used in public health and the molecular basis of insecticide resistance were established.ResultsAn. funestus (sensu stricto) (s.s.) was the predominant mosquito species found resting inside the houses in Obuasi, while at Adawukwa it was found together with An. coluzzii. Parasite rates were high in An. funestus (s.s.) populations from both localities, with Plasmodium infection rates greater than 12.5 %. Both, An. funestus (s.s.) and An. coluzzii, from the two sites exhibited high resistance to the insecticide from various classes including the pyrethroids, carbamates and DDT, but remained fully susceptible to the organophosphates. A preliminary characterization of the underlying molecular mechanisms of resistance in An. funestus (s.s.) populations from both sites revealed that CYP6P9a, CYP6P9b, CYP6M7 and GSTe2 genes are upregulated, markedly higher in Obuasi (between 3.35 and 1.83 times) than in Adawukwa population. The frequency of L119F-GSTe2 and A296S-RDL resistance markers were also higher in Obuasi (42.5 and 68.95 % higher), compared with An. funestus (s.s.) populations from Adawukwa. These findings suggest that the similar resistance pattern observed in both An. funestus (s.s.) populations are driven by different mechanisms.ConclusionsResistance to multiple insecticides in public health use is present in malaria vectors from Ghana with major resistance genes already operating in the field. This should be taken into consideration in the design of resistance management strategies to avoid operational failure.
KW - An. coluzzii
KW - An. funestus
KW - An. gambiae
KW - Ghana
KW - Insecticide resistance
KW - Malaria
KW - Vector control
U2 - 10.1186/s13071-016-1787-8
DO - 10.1186/s13071-016-1787-8
M3 - Article
SN - 1756-3305
VL - 9
JO - Parasites and Vectors
JF - Parasites and Vectors
IS - 1
M1 - 504
ER -
