scholarly journals Intensity of pyrethroid resistance in Anopheles culicifacies s.l. (Diptera: Culicidae) in Odisha State, India

2020 ◽  
Vol 114 (4) ◽  
pp. 205-211 ◽  
Author(s):  
Sudhansu Sekhar Sahu ◽  
Sonia Thankachy ◽  
Smrutidhara Dash ◽  
Gunasekaran Kasinathan ◽  
Ashwani Kumar
Keyword(s):  
Pyrethroid Resistance ◽  
Anopheles Culicifacies

DDT resistance in Anopheles culicifacies Giles and A. subpictus Grassi (Diptera: Culicidae) from Sri Lanka: a field study on the mechanisms and changes in gene frequency after cessation of DDT spraying

1988 ◽  
Vol 78 (4) ◽  
pp. 717-723 ◽  
Author(s):  
P. R. J. Herath ◽  
K. G. I. Jayawardena ◽  
J. Hemingway ◽  
J. Harris
Keyword(s):  
Sri Lanka ◽  
Selection Pressure ◽  
Gene Frequency ◽  
Glutathione Transferase ◽  
Pyrethroid Resistance ◽  
Transferase Activity ◽  
Anopheles Culicifacies ◽  
Agricultural Use ◽  
Ddt Resistance ◽  
Susceptibility Tests

AbstractThe frequency of DDT resistance in Anopheles culicifacies Giles in Sri Lanka remained relatively constant from the cessation of DDT use for malaria control in 1975 until 1982. From 1983 to 1986, the frequency of resistance decreased slowly but significantly. In contrast, the resistance gene frequency in A. subpictus Grassi declined between 1980 and 1983, after which the trend was reversed, and there was a significant increase in DDT resistance in 1984–86. This rise in DDT resistance cannot be attributed to positive DDT selection pressure as there has been little or no agricultural use of DDT during this period. It is also unlikely that the rise in resistance is due to pyrethroid selection as the quantity of pyrethroids used on the island is low and there is no evidence of pyrethroid resistance from WHO susceptibility tests. Studies with the synergists FDMC (4-chloro-α-(4-chlorophenyl)-α-(trifluoromethyl)benzenemethanol) and piperonyl butoxide indicated the involvement of DDT-dehydrochlorinase rather than oxidase in the resistance. This was confirmed by metabolism studies, as DDT-resistant adults of both A. culicifacies and A. subpictus showed an increase in the rate of DDE production, which was also correlated with an increase in glutathione transferase activity.

scholarly journals Efficacy evaluation of Veeralin LN, a PBO-incorporated alpha-cypermethrin long-lasting insecticidal net against Anopheles culicifacies in experimental huts in Odisha State

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Gunasekaran Kasinathan ◽  
Sudhansu Sekhar Sahu ◽  
Nallan Krishnamoorthy ◽  
Mohammed Mustafa Baig ◽  
Sonia Thankachy ◽  
...  
Keyword(s):  
Pyrethroid Resistance ◽  
Blood Feeding ◽  
Malaria Vectors ◽  
Current Phase ◽  
Anopheles Culicifacies ◽  
Vector Species ◽  
Efficacy Evaluation ◽  
Experimental Huts ◽  
Long Lasting Insecticidal Nets ◽  
Better Than

Abstract Background The success of malaria control using long-lasting insecticidal nets (LLINs) is threatened by pyrethroid resistance developed by the malaria vectors, worldwide. To combat the resistance, synergist piperonyl butoxide (PBO) incorporated LLINs is one of the available options. In the current phase II hut trial, the efficacy of Veeralin®LN (an alpha-cypermethrin and PBO-incorporated net) was evaluated against Anopheles culicifacies, a pyrethroid resistant malaria vector. Methods The performance of Veeralin®LN was compared with MAGNet®LN and untreated net in reducing the entry, induced exit, mortality and blood feeding inhibition of target vector species. Results The performance of Veeralin was equal to MAGNet in terms of reducing hut entry, inhibiting blood feeding and inducing exophily, and with regard to causing mortality Veeralin was better than MAGNet. When compared to untreated net, a significant reduction in hut entry and blood feeding and an increase in exophily and mortality were observed with Veeralin. In cone bioassays, unwashed Veeralin caused > 80% mortality of An. culicifacies. Conclusions Veeralin performed equal to (entry, exit, feeding) or better than (mortality in huts and cone bioassays) MAGNet and could be an effective tool against pyrethroid resistant malaria vectors.

scholarly journals Escalation of Pyrethroid Resistance in the Malaria Vector Anopheles funestus Induces a Loss of Efficacy of Piperonyl Butoxide–Based Insecticide-Treated Nets in Mozambique

2019 ◽  
Vol 220 (3) ◽  
pp. 467-475 ◽  
Author(s):  
Jacob M Riveron ◽  
Silvie Huijben ◽  
Williams Tchapga ◽  
Magellan Tchouakui ◽  
Murielle J Wondji ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Pyrethroid Resistance ◽  
Anopheles Funestus ◽  
Resistance Mechanisms ◽  
Piperonyl Butoxide ◽  
Insecticide Treated Nets ◽  
Molecular Analyses ◽  
Cytochrome P450 Genes ◽  
High Degree ◽  
Long Lasting Insecticidal Nets

Abstract Background Insecticide resistance poses a serious threat to insecticide-based interventions in Africa. There is a fear that resistance escalation could jeopardize malaria control efforts. Monitoring of cases of aggravation of resistance intensity and its impact on the efficacy of control tools is crucial to predict consequences of resistance. Methods The resistance levels of an Anopheles funestus population from Palmeira, southern Mozambique, were characterized and their impact on the efficacy of various insecticide-treated nets established. Results A dramatic loss of efficacy of all long-lasting insecticidal nets (LLINs), including piperonyl butoxide (PBO)–based nets (Olyset Plus), was observed. This An. funestus population consistently (2016, 2017, and 2018) exhibited a high degree of pyrethroid resistance. Molecular analyses revealed that this resistance escalation was associated with a massive overexpression of the duplicated cytochrome P450 genes CYP6P9a and CYP6P9b, and also the fixation of the resistance CYP6P9a_R allele in this population in 2016 (100%) in contrast to 2002 (5%). However, the low recovery of susceptibility after PBO synergist assay suggests that other resistance mechanisms could be involved. Conclusions The loss of efficacy of pyrethroid-based LLINs with and without PBO is a concern for the effectiveness of insecticide-based interventions, and action should be taken to prevent the spread of such super-resistance.

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