Evaluation of piperonyl butoxide in enhancing the efficacy of pyrethroid insecticides against resistant Anopheles gambiae s.l. in Ghana

Dadzie, Samuel; Chabi, Joseph; Asafu-Adjaye, A.; Owusu-Akrofi, Otubea; Baffoe-Wilmot, Aba; Malm, Keziah; Bart-Plange, Constance; Coleman, Sylvester; Appawu, Maxwell A.; Boakye, Daniel

doi:10.1186/s12936-017-1960-3

Cited by 54 publications

(45 citation statements)

References 43 publications

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“…This could further explain why there were no signi cant difference in frequencies between the indoor and outdoor populations. Notably, resistance has been previously reported at varying levels to DDT and deltamethrin across all vector species in Ghana [53,56] and the neighboring countries including Benin [19], Burkina Faso [27] and Togo [57]. High frequencies of resistance loci may compromise the effectiveness of vector control in the study areas that could subsequently accentuate residual transmission [41].…”

Section: Discussionmentioning

confidence: 86%

Insecticide resistance in indoor and outdoor-resting Anopheles gambiae s.l. in Northern Ghana

Hamid-Adiamoh

Amambua-Ngwa

Nwakanma

et al. 2020

Preprint

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Background: Selection pressure from continued exposure to insecticides drives the development of insecticide resistance and changes in resting behavior of malaria vectors, which may support residual transmission in several endemic settings. There is a need to understand how resistance drives changes in resting behavior within vector species. Here, we examined the association between insecticide resistance and resting behavior of Anopheles gambiae s.l. in Northern Ghana. Methods: Adult mosquitoes were collected both indoors and outdoors from two communities using mouth aspirators and pit shelters. F1 progenies from a subset of mosquitoes were exposed to dichloro diphenyl trichloroethane (DDT), deltamethrin, malathion and bendiocarb using WHO insecticide susceptibility tests. Insecticide resistance markers including voltage-gated sodium channel (Vgsc)- 1014F, Vgsc-1014S, Vgsc-1575Y, glutathione-S-transferase epsilon 2 (GSTe2)-114T and acetylcholinesterase (Ace1)-119S, as well as blood meal sources were investigated using PCR methods. Activities of metabolic enzymes, acetylcholine esterase (AChE), non-specific β-esterases, glutathione-S-transferase (GST) and monooxygenases (oxidases) were measured from unexposed F1 progenies using microplate assays. Results: Susceptibility of An. coluzzii to deltamethrin 24hr post-exposure was significantly higher in indoor (mortality=5%) than the outdoor (mortality=2.5%) populations (P=0.02). The mosquitoes were fully susceptible to malathion (mortality: indoor=98%, outdoor=100%). Susceptibility to DDT was significantly higher in outdoor (mortality=9%) than indoor (mortality=0%) mosquitoes (P=0.006). Mosquitoes were also found with suspected resistance to bendiocarb but mortality was not statistically different (mortality: indoor=90%, outdoor=95%. P=0.30). The frequencies of all resistance alleles were higher in F1 outdoor (0.11-0.85) than indoor (0.04-0.65) mosquito populations, while Vgsc-1014F in F0 An. gambiae s.s significantly associated with outdoor-resting behavior (P=0.01). Activities of non-specific β-esterase enzymes were significantly higher in outdoor than indoor mosquitoes (Mean enzyme activity: Outdoor=: 1.70/mg protein; Indoor=1.35/mg protein. P<0.0001). AChE activity was also more elevated in outdoor (0.62/mg protein) than indoor (0.57/mg protein) mosquitoes but this was not significant (P=0.08). Human blood index (HBI) was predominantly detected in indoor (18%) than the outdoor mosquito population (3%). Conclusions: These findings revealed higher phenotypic resistance in indoor than outdoor-resting mosquitoes, but genotypic and metabolic resistance levels were higher in outdoor than the indoor mosquito populations. However, the overall results did not establish that there was a significant preference of resistant malaria vectors to solely rest indoors or outdoors, but varied depending on the resistant alleles present. Indication that human and animal blood meal indices were more prevalent in indoor-resting mosquitoes was also shown. Continued monitoring of changes in resting behavior within An. gambiae s.l. populations is recommended.

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Section: Discussionmentioning

confidence: 86%

Insecticide resistance in indoor and outdoor-resting Anopheles gambiae s.l. in Northern Ghana

Hamid-Adiamoh

Amambua-Ngwa

Nwakanma

et al. 2020

Preprint

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“…In An . gambiae , PBO also significantly enhanced the susceptibility to pyrethroids 38 . It should be noted that results from PBO assays must be interpreted with caution, since PBO is not entirely specific for cytochrome P450.…”

Section: Discussionmentioning

confidence: 90%

Detoxification mechanisms involved in ivermectin resistance in the cattle tick, Rhipicephalus (Boophilus) microplus

Gall

Klafke

Torres

2018

Sci Rep

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The cattle tick Rhipicephalus microplus is one of the most important ectoparasites with great sanitary and economic impact for cattle rearing worldwide. Ivermectin is commonly used to control tick populations, but its use over the last 30 years has led to the development of resistant populations of R. microplus, and a concomitant loss of efficacy. In this context, we aimed to determine the metabolic mechanisms that contribute to ivermectin resistance in a resistant strain of this species. We performed lethal time bioassays with inhibitors of detoxifying enzymes and xenobiotic transporters (four detoxification pathways) using two strains of ticks: a susceptible strain, Mozo, and a resistant strain, Juarez. We used four inhibitors to test the involvement of different families of proteins responsible for detoxification of ivermectin, namely cytochrome P450, esterases, glutathione-S-transferase, and ATP Binding Cassette Transporters. We calculated the synergistic factor for each inhibitor and strain. To different degrees, all tested inhibitors altered the mortality rates in the strain Juarez, indicating that multiple mechanisms are responsible for the resistant phenotype. Detoxification mechanisms mediated by ABC transporters were observed to be the most important. Esterases, glutathione-S-transferases, and cytochrome-oxidases played less important roles in detoxification.

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“…PBO+deltamethrin and PBO+permethrin incorporated, respectively (Ketoh et al 2018). Also, a study by Dadzie et al (2017) in Ghana, reported the role of PBO in enhancing the efficacy of pyrethroid insecticides against An. gambiae s.l.…”

Section: Discussionmentioning

confidence: 99%

Pyrethroid Resistance Intensity ofAnopheles gambiae sensu lato(Diptera: Culicidae) from Phase II Hut Trial Station in KOLOKOPE, Eastern Plateau Togo: A Potential Site to Assess the Next Generation of Long-Lasting Insecticidal Nets

Ahadji-Dabla

Chabi

Apétogbo

et al. 2020

Preprint

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Per WHO recommendations, the implementation of the next-generation of Long Lasting Insecticidal Nets (LLINs) for malaria vector control requires appropriate investigations on the insecticide resistance profile of the vector and the impact of the LLINs on the known resistant mosquitoes. The next-generation of LLINs are actually an incorporation of a mixture of pyrethroid insecticides and a synergist such as PBO. Several studies have proven the additional impact of PBO on the increase in the mortality rate of Anopheles gambiae s.l. (Diptera: Culicidae). However, further assessments need to be done at community level in order to set a stage for the acceleration of the WHO policies on the implementation of the next-generation of LLINs. Kolokope is a cotton-growing area in the central region of Togo characterized by an intensive use of agro pesticides and insecticides. A phase II experimental hut station for the evaluation of mosquito control tools has been built in Kolokope. For the characterization of the site, WHO susceptibility tests using diagnostic doses of eight insecticides, PBO synergist assay and intensity assay of three pyrethroids (5x and 10x) were conducted on adult female mosquitoes obtained from larvae collected around the site. Anopheles gambiae s.l. from Kolokope showed high resistance to pyrethroids and DDT, but in lesser extent to carbamates and organophosphates. Likewise, high intensity of resistance to pyrethroid was observed with less than 40% mortality at 10x deltamethrin, 52 and 29% mortality at 10x permethrin and 10x alphacypermethrin, respectively. Also, the addition of PBO showed a reversal mortality which was similar to mortality rate at 10x doses of pyrethroids. The high pyrethroid intensity resistance recorded at Kolokope could be mainly due to the pressure on An. gambiae s.l. through the excessive use of insecticide in agriculture. This can be used for the assessment of the next-generation of LLINs either in experimental hut or at a community trial.

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Evaluation of piperonyl butoxide in enhancing the efficacy of pyrethroid insecticides against resistant Anopheles gambiae s.l. in Ghana

Cited by 54 publications

References 43 publications

Insecticide resistance in indoor and outdoor-resting Anopheles gambiae s.l. in Northern Ghana

Insecticide resistance in indoor and outdoor-resting Anopheles gambiae s.l. in Northern Ghana

Detoxification mechanisms involved in ivermectin resistance in the cattle tick, Rhipicephalus (Boophilus) microplus

Pyrethroid Resistance Intensity ofAnopheles gambiae sensu lato(Diptera: Culicidae) from Phase II Hut Trial Station in KOLOKOPE, Eastern Plateau Togo: A Potential Site to Assess the Next Generation of Long-Lasting Insecticidal Nets

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