scholarly journals Anopheles gambiae (s.l.) exhibit high intensity pyrethroid resistance throughout Southern and Central Mali (2016–2018): PBO or next generation LLINs may provide greater control

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Arthur Sovi ◽  
Chitan Keita ◽  
Youssouf Sinaba ◽  
Abdourhamane Dicko ◽  
Ibrahim Traore ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
High Intensity ◽  
Pyrethroid Resistance ◽  
Next Generation ◽  
Anopheles Gambiae S.L

scholarly journals Anopheles gambiae (s.l.) exhibit high intensity pyrethroid resistance throughout Southern and Central Mali (2016–2018): PBO or next generation LLINs may provide greater control

2020 ◽  
Author(s):  
Arthur Sovi ◽  
Chitan Keita ◽  
Youssouf Sinaba ◽  
Abdourhamane Dicko ◽  
Ibrahim Traore ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
High Intensity ◽  
Pyrethroid Resistance ◽  
Fold Increase ◽  
Malaria Vectors ◽  
Effective Control ◽  
Pirimiphos Methyl ◽  
Anopheles Gambiae S.L ◽  
Agricultural Use ◽  
Rotation Strategy

Abstract Background: Millions of pyrethroid LLINs have been distributed in Mali during the past 20 years which, along with agricultural use, has increased the selection pressure on malaria vector populations. This study investigated pyrethroid resistance intensity and susceptible status of malaria vectors to alternative insecticides to guide choice of insecticides for LLINs and IRS for effective control of malaria vectors. Methods: For 3 years between 2016 and 2018, susceptibility testing was conducted annually in 14–16 sites covering southern and central Mali. Anopheles gambiae (s.l.) were collected from larval sites and adult mosquitoes exposed in WHO tube tests to diagnostic doses of bendiocarb (0.1%) and pirimiphos-methyl (0.25%). Resistance intensity tests were conducted using CDC bottle bioassays (2016–2017) and WHO tube tests (2018) at 1×, 2×, 5×, and 10× the diagnostic concentration of permethrin, deltamethrin and alpha-cypermethrin. WHO tube tests were conducted with pre-exposure to the synergist PBO followed by permethrin or deltamethrin. Chlorfenapyr was tested in CDC bottle bioassays at 100 µg active ingredient per bottle and clothianidin at 2% in WHO tube tests. PCR was performed to identify species within the An. gambiae complex. Results: In all sites An. gambiae (s.l.) showed high intensity resistance to permethrin and deltamethrin in CDC bottle bioassay tests in 2016 and 2017. In 2018, the WHO intensity tests resulted in survivors at all sites for permethrin, deltamethrin and alpha-cypermethrin when tested at 10× the diagnostic dose. Across all sites mean mortality was 33.7% with permethrin (0.75%) compared with 71.8% when pre-exposed to PBO (4%), representing a 2.13-fold increase in mortality. A similar trend was recorded for deltamethrin. There was susceptibility to pirimiphos-methyl, chlorfenapyr and clothianidin in all surveyed sites, including current IRS sites in Mopti Region. An. coluzzii was the primary species in 4 of 6 regions. Conclusions: Widespread high intensity pyrethroid resistance was recorded during 2016–2018 and is likely to compromise the effectiveness of pyrethroid LLINs in Mali. PBO or chlrofenapyr LLINs should provide improved control of An. gambiae (s.l.). Clothianidin and pirimiphos-methyl insecticides are currently being used for IRS as part of a rotation strategy based on susceptibility being confirmed in this study.

scholarly journals Evidence supporting deployment of next generation insecticide treated nets in Burkina Faso: bioassays with either chlorfenapyr or piperonyl butoxide increase mortality of pyrethroid-resistant Anopheles gambiae s.l.

2021 ◽  
Author(s):  
Sawdetuo Aristide HIEN ◽  
Dieudonné D. Soma ◽  
Dramane Coulibaly ◽  
Abdoulaye Diabaté ◽  
Allison Belemvire ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Anopheles Gambiae ◽  
High Intensity ◽  
Large Scale ◽  
Pyrethroid Resistance ◽  
Piperonyl Butoxide ◽  
Sub Saharan Africa ◽  
Insecticide Treated Nets ◽  
Bobo Dioulasso ◽  
Sub Saharan

Abstract Background Pyrethroid resistance poses a major threat to the efficacy of insecticide treated nets (ITNs) in Burkina Faso and throughout sub-Saharan Africa, particularly when resistance is present at high intensity. For such areas there are alternative ITNs available, including the synergist piperonyl butoxide (PBO)-based ITNs and dual active ingredient ITNs such as Interceptor G2 (treated with chlorfenapyr and alpha-cypermethrin). Before deploying alternative ITNs on a large scale it is crucial to characterize the resistance profiles of primary malaria vector species for evidence-based decision making Methods Larvae from the predominant vector, Anopheles gambiae s.l., were collected from 15 sites located throughout Burkina Faso and reared to adults for bioassays to assess insecticide resistance status. Resistance intensity assays were conducted using WHO tube tests to determine the level of resistance to pyrethroids commonly used on ITNs at 1x, 5x and 10x times the diagnostic dose. WHO tube tests were also used for PBO synergist bioassays with deltamethrin and permethrin. Bottle bioassays were conducted to determine susceptibility to chlorfenapyr at a dose of 100µg/bottle. Results WHO tube tests revealed high intensity resistance in An. gambiae s.l. to deltamethrin and alpha-cypermethrin in all sites tested. Resistance intensity to permethrin was either moderate or high in 13 sites. PBO pre-exposure followed by deltamethrin restored full susceptibility in 1 site but partially restored susceptibility in all but one of the remaining sites (often reaching mortality greater than 80%). PBO pre-exposure followed by permethrin partially restored susceptibility in 12 sites. There was no significant increase in permethrin mortality after PBO pre-exposure in Kampti, Karangasso-Vigué or Mangodara; while in Seguenega, Orodara and Bobo-Dioulasso there was a significant increase in mortality, but rates remained below 50%. Susceptibility to chlorfenapyr was confirmed in 14 sites. Conclusion High pyrethroid resistance intensity in An. gambiae s.l. is widespread across Burkina Faso and may be a predictor of reduced pyrethroid ITN effectiveness. PBO + deltamethrin ITNs would likely provide greater control than pyrethroid nets. However, since susceptibility in bioassays was not restored in most sites following pre-exposure to PBO, Interceptor G2 may be a better long-term solution as susceptibility was recorded to chlorfenapyr in nearly all sites. This study provides evidence supporting the introduction of both Interceptor G2 nets and PBO nets, which were distributed in Burkina Faso in 2019 as part of a mass campaign.

scholarly journals Evidence supporting deployment of next generation insecticide treated nets in Burkina Faso: bioassays with either chlorfenapyr or piperonyl butoxide increase mortality of pyrethroid-resistant Anopheles gambiae

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Aristide S. Hien ◽  
Dieudonné D. Soma ◽  
Samina Maiga ◽  
Dramane Coulibaly ◽  
Abdoulaye Diabaté ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Anopheles Gambiae ◽  
High Intensity ◽  
Large Scale ◽  
Pyrethroid Resistance ◽  
Piperonyl Butoxide ◽  
Sub Saharan Africa ◽  
Insecticide Treated Nets ◽  
Bobo Dioulasso ◽  
Sub Saharan

Abstract Background Pyrethroid resistance poses a major threat to the efficacy of insecticide-treated nets (ITNs) in Burkina Faso and throughout sub-Saharan Africa, particularly where resistance is present at high intensity. For such areas, there are alternative ITNs available, including the synergist piperonyl butoxide (PBO)-based ITNs and dual active ingredient ITNs such as Interceptor G2 (treated with chlorfenapyr and alpha-cypermethrin). Before deploying alternative ITNs on a large scale it is crucial to characterize the resistance profiles of primary malaria vector species for evidence-based decision making. Methods Larvae from the predominant vector, Anopheles gambiae sensu lato (s.l.) were collected from 15 sites located throughout Burkina Faso and reared to adults for bioassays to assess insecticide resistance status. Resistance intensity assays were conducted using WHO tube tests to determine the level of resistance to pyrethroids commonly used on ITNs at 1×, 5 × and 10 × times the diagnostic dose. WHO tube tests were also used for PBO synergist bioassays with deltamethrin and permethrin. Bottle bioassays were conducted to determine susceptibility to chlorfenapyr at a dose of 100 µg/bottle. Results WHO tube tests revealed high intensity resistance in An. gambiae s.l. to deltamethrin and alpha-cypermethrin in all sites tested. Resistance intensity to permethrin was either moderate or high in 13 sites. PBO pre-exposure followed by deltamethrin restored full susceptibility in one site and partially restored susceptibility in all but one of the remaining sites (often reaching mortality greater than 80%). PBO pre-exposure followed by permethrin partially restored susceptibility in 12 sites. There was no significant increase in permethrin mortality after PBO pre-exposure in Kampti, Karangasso-Vigué or Mangodara; while in Seguenega, Orodara and Bobo-Dioulasso there was a significant increase in mortality, but rates remained below 50%. Susceptibility to chlorfenapyr was confirmed in 14 sites. Conclusion High pyrethroid resistance intensity in An. gambiae s.l. is widespread across Burkina Faso and may be a predictor of reduced pyrethroid ITN effectiveness. PBO + deltamethrin ITNs would likely provide greater control than pyrethroid nets. However, since susceptibility in bioassays was not restored in most sites following pre-exposure to PBO, Interceptor G2 may be a better long-term solution as susceptibility was recorded to chlorfenapyr in nearly all sites. This study provides evidence supporting the introduction of both Interceptor G2 nets and PBO nets, which were distributed in Burkina Faso in 2019 as part of a mass campaign.

scholarly journals Evidence that agricultural use of pesticides selects pyrethroid resistance within Anopheles gambiae s.l. populations from cotton growing areas in Burkina Faso, West Africa

PLoS ONE ◽  
2017 ◽  
Vol 12 (3) ◽  
pp. e0173098 ◽  
Author(s):  
Aristide Sawdetuo Hien ◽  
Dieudonné Diloma Soma ◽  
Omer Hema ◽  
Bazoma Bayili ◽  
Moussa Namountougou ◽  
...  
Keyword(s):  
West Africa ◽  
Burkina Faso ◽  
Anopheles Gambiae ◽  
Pyrethroid Resistance ◽  
Anopheles Gambiae S.L ◽  
Agricultural Use

scholarly journals An. gambiae s.l. exhibit high intensity pyrethroid resistance throughout Southern and Central Mali (2016-2018); PBO or next generation LLINs may provide greater control

2020 ◽  
Author(s):  
Arthur Sovi ◽  
Chitan Keita ◽  
Youssouf Sinaba ◽  
Abdourhamane Dicko ◽  
Ibrahim Traore ◽  
...  
Keyword(s):  
High Intensity ◽  
Pyrethroid Resistance ◽  
Fold Increase ◽  
Malaria Vectors ◽  
Effective Control ◽  
The Past ◽  
Pirimiphos Methyl ◽  
Anopheles Gambiae S.L ◽  
Agricultural Use ◽  
Rotation Strategy

Abstract Background: Millions of pyrethroid LLINs have been distributed in Mali during the past 20 years which, along with agricultural use, has increased the selection pressure on malaria vector populations. This study investigated pyrethroid resistance intensity and susceptible status of malaria vectors to alternative insecticides to guide choice of insecticides for LLINs and IRS for effective control of malaria vectors. Methods: For 3 years between 2016 and 2018, susceptibility testing was conducted annually in 14-16 sites covering southern and central Mali. Anopheles gambiae s.l. were collected from larval sites and adult mosquitoes exposed in WHO tube tests to diagnostic doses of bendiocarb (0.1%) and pirimiphos-methyl (0.25%). Resistance intensity tests were conducted using CDC bottle bioassays (2016-17) and WHO tube tests (2018) at 1 × , 2 × , 5 × , and 10 × the diagnostic concentration of permethrin, deltamethrin and alpha-cypermethrin. WHO tube tests were conducted with pre-exposure to the synergist PBO followed by permethrin or deltamethrin. Chlorfenapyr was tested in CDC bottle bioassays at 100µg active ingredient per bottle and clothianidin at 2% in WHO tube tests. PCR was performed to identify species within the An. gambiae complex. Results: In all sites An. gambiae s.l. showed high intensity resistance to permethrin and deltamethrin in CDC bottle bioassay tests in 2016 and 2017. In 2018, WHO intensity tests resulted in survivors at all sites for permethrin, deltamethrin and alpha-cypermethrin when tested at 10× the diagnostic dose. Across all sites mean mortality was 33.7% with permethrin (0.75%) compared with 71.8% when pre-exposed to PBO (4%), representing a 2.13 fold increase in mortality. A similar trend was recorded for deltamethrin. There was susceptibility to pirimiphos-methyl, chlorfenapyr and clothianidin in all surveyed sites, including current IRS sites in Mopti Region. An. coluzzii was the primary species in 4 of 6 regions. Conclusions: Widespread high intensity pyrethroid resistance was recorded during 2016-18 and is likely to compromise the effectiveness of pyrethroid LLINs in Mali. PBO or chlrofenapyr LLINs should provide improved control of An. gambiae s.l. Clothianidin and pirimiphos-methyl insecticides are currently being used for IRS as part of a rotation strategy based on susceptibility being confirmed in this study.

scholarly journals Pyrethroid Resistance Intensity of Anopheles 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

2020 ◽  
Author(s):  
Koffi Mensah Ahadji-Dabla ◽  
Joseph Chabi ◽  
Georges Apétogbo ◽  
Edoh Koffi ◽  
Melinda Patricia Hadi ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Anopheles Gambiae ◽  
Phase Ii ◽  
Pyrethroid Resistance ◽  
Malaria Vector Control ◽  
Next Generation ◽  
Pyrethroid Insecticides ◽  
Experimental Hut ◽  
The Impact ◽  
Long Lasting Insecticidal Nets

AbstractPer 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. Kolokopé 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 Kolokopé. 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 Kolokopé 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 Kolokopé 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.

scholarly journals An. gambiae s.l. exhibit high intensity pyrethroid resistance throughout Southern and Central Mali (2016-2018); PBO or next generation LLINs may provide greater control

2020 ◽  
Author(s):  
Arthur Sovi ◽  
Chitan Keita ◽  
Youssouf Sinaba ◽  
Abdourhamane Dicko ◽  
Ibrahim Traore ◽  
...  
Keyword(s):  
High Intensity ◽  
Pyrethroid Resistance ◽  
Fold Increase ◽  
Malaria Vectors ◽  
Effective Control ◽  
The Past ◽  
Pirimiphos Methyl ◽  
Anopheles Gambiae S.L ◽  
Agricultural Use ◽  
Rotation Strategy

Abstract Background: Millions of pyrethroid LLINs have been distributed in Mali during the past 20 years which, along with agricultural use, has increased the selection pressure on malaria vector populations. This study investigated pyrethroid resistance intensity and susceptible status of malaria vectors to alternative insecticides to guide choice of insecticides for LLINs and IRS for effective control of malaria vectors. Methods: For 3 years between 2016 and 2018, susceptibility testing was conducted annually in 14-16 sites covering southern and central Mali. Anopheles gambiae s.l. were collected from larval sites and adult mosquitoes exposed in WHO tube tests to diagnostic doses of bendiocarb (0.1%) and pirimiphos-methyl (0.25%). Resistance intensity tests were conducted using CDC bottle bioassays (2016-17) and WHO tube tests (2018) at 1 × , 2 × , 5 × , and 10 × the diagnostic concentration of permethrin, deltamethrin and alpha-cypermethrin. WHO tube tests were conducted with pre-exposure to the synergist PBO followed by permethrin or deltamethrin. Chlorfenapyr was tested in CDC bottle bioassays at 100µg active ingredient per bottle and clothianidin at 2% in WHO tube tests. PCR was performed to identify species within the An. gambiae complex. Results: In all sites An. gambiae s.l. showed high intensity resistance to permethrin and deltamethrin in CDC bottle bioassay tests in 2016 and 2017. In 2018, WHO intensity tests resulted in survivors at all sites for permethrin, deltamethrin and alpha-cypermethrin when tested at 10× the diagnostic dose. Across all sites mean mortality was 33.7% with permethrin (0.75%) compared with 71.8% when pre-exposed to PBO (4%), representing a 2.13 fold increase in mortality. A similar trend was recorded for deltamethrin. There was susceptibility to pirimiphos-methyl, chlorfenapyr and clothianidin in all surveyed sites, including current IRS sites in Mopti Region. An. coluzzii was the primary species in 4 of 6 regions. Conclusions: Widespread high intensity pyrethroid resistance was recorded during 2016-18 and is likely to compromise the effectiveness of pyrethroid LLINs in Mali. PBO or chlrofenapyr LLINs should provide improved control of An. gambiae s.l. Clothianidin and pirimiphos-methyl insecticides are currently being used for IRS as part of a rotation strategy based on susceptibility being confirmed in this study.

scholarly journals Effect of naturally occurring Wolbachia in Anopheles gambiae s.l. mosquitoes from Mali on Plasmodium falciparum malaria transmission

2017 ◽  
Vol 114 (47) ◽  
pp. 12566-12571 ◽  
Author(s):  
Fabio M. Gomes ◽  
Bretta L. Hixson ◽  
Miles D. W. Tyner ◽  
Jose Luis Ramirez ◽  
Gaspar E. Canepa ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Anopheles Gambiae ◽  
Malaria Transmission ◽  
Deleterious Effect ◽  
Plasmodium Falciparum Malaria ◽  
Anopheles Coluzzii ◽  
Naturally Occurring ◽  
Anopheles Gambiae S.L ◽  
Cat Fleas ◽  
Sporozoite Infection

A naturally occurring Wolbachia strain (wAnga-Mali) was identified in mosquitoes of the Anopheles gambiae complex collected in the Malian villages of Dangassa and Kenieroba. Phylogenetic analysis of the nucleotide sequence of two 16S rRNA regions showed that wAnga-Mali clusters with Wolbachia strains from supergroup A and has the highest homology to a Wolbachia strain isolated from cat fleas (Ctenocephalides). wAnga-Mali is different from two Wolbachia strains previously reported in A. gambiae from Burkina Faso (wAnga_VK5_STP and wAnga_VK5_3.1a). Quantitative analysis of Wolbachia and Plasmodium sporozoite infection in field-collected mosquitoes indicates that the prevalence and intensity of Plasmodium falciparum sporozoite infection is significantly lower in Wolbachia-infected females. The presence of Wolbachia in females from a laboratory Anopheles coluzzii (A. gambiae, M form) colony experimentally infected with P. falciparum (NF54 strain) gametocyte cultures slightly enhanced oocyst infection. However, Wolbachia infection significantly reduced the prevalence and intensity of sporozoite infection, as observed in the field. This indicates that wAnga-Mali infection does not limit early stages of Plasmodium infection in the mosquito, but it has a strong deleterious effect on sporozoites and reduces malaria transmission.

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