Short and long term evaluation of the efficiency of PermaNet® 2.0 bed net against environmental factors and washing using bioassay tests

Kayedi, Mohammad Hassan; Khamisabadi, Kiumars; Haghdoost, Ali Akbar; Kayedi, Zohreh; Fallahi, Shirzad; Abdali, Nargess

doi:10.1590/s1678-9946201759018

Cited by 3 publications

(3 citation statements)

References 20 publications

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“…The bioassay results were surprising, as they showed very low mortality rates even after only 6 months of use. Permanet 2.0® have previously been shown to retain insecticidal efficacy after 20 washes and 2–3 years of use [ 25 – 27 ]. It is worrisome that LLINs with only 6 months of use had such low mortality rates.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the durability and use of long‐lasting insecticidal nets in Nicaragua

Villalta

Bravo²,

Vizcaino

et al. 2021

Malar J

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Background Vector control for malaria prevention relies most often on the use of insecticide-treated bed net (ITNs) and indoor residual spraying. Little is known about the longevity of long-lasting insecticidal nets (LLINs) in the Americas. The physical integrity and insecticide retention of LLINs over time were monitored after a bed net distribution campaign to assess community practices around LLIN care and use in Waspam, northeastern Nicaragua. Methods At least 30 nets were collected at 6, 12, 24, and 36 months post distribution. Physical integrity was measured by counting holes and classifying nets into categories (good, damaged, and too torn) depending on a proportionate hole index (pHI). Insecticide bioefficacy was assessed using cone bioassays, and insecticide content measured using a cyanopyrethroid field test (CFT). Results At 6 months, 87.3 % of LLINs were in good physical condition, while by 36 months this decreased to 20.6 %, with 38.2 % considered ‘too torn.’ The median pHI increased from 7 at the 6-month time point to 480.5 by 36 months. After 36 months of use, median mortality in cone bioassays was 2 % (range: 0–6 %) compared to 16 % (range: 2–70 %) at 6 months. There was a decrease in the level of deltamethrin detected on the surface of the LLINs with 100 % of tested LLINs tested at 12 months and 24 months crossing the threshold for being considered a failed net by CFT. Conclusions This first comprehensive analysis of LLIN durability in Central America revealed rapid loss of chemical bioefficacy and progressive physical damage over a 36-month period. Use of these findings to guide future LLIN interventions in malaria elimination settings in Nicaragua, and potentially elsewhere in the Americas, could help optimize the successful implementation of vector control strategies.

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Section: Discussionmentioning

confidence: 99%

Evaluation of the durability and use of long‐lasting insecticidal nets in Nicaragua

Villalta

Bravo²,

Vizcaino

et al. 2021

Malar J

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“…coluzzii in the Diébougou area carrying a kdr-e resistant allele significantly increased with both the time since LLIN distribution (up to 12 months after distribution) and the % of LLIN users in the village population. PermaNet 2.0 LLINs have been shown to retain their insecticidal efficacy under field conditions for at least one year after distribution (Djènontin, Alfa, et al, 2023; Kayedi et al, 2017; Kilian et al, 2008; Tan et al, 2016), exerting high selective pressure on vectors over this period at least. In contrast, there was no significant association between any of the target-site mutations and any of the crop-related variable.…”

Section: Discussionmentioning

confidence: 99%

Physiological and behavioural resistance of malaria vectors in rural West-Africa : a data mining study to address their fine-scale spatiotemporal heterogeneity, drivers, and predictability

Taconet

Soma

Zogo

et al. 2022

Preprint

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Insecticide resistance and behavioral adaptation of malaria mosquitoes impact the efficacy of long-lasting insecticide nets - currently the main malaria vector control tool. To develop and deploy complementary, efficient and cost-effective control interventions, a good understanding of the drivers of these physiological and behavioural traits is needed. In this data-mining work, we modeled a set of indicators of physiological resistances to insecticide (prevalence of three target-site mutations) and biting behaviours (early- and late-biting, exophagy) of anopheles mosquitoes in two rural areas of West-Africa, located in Burkina Faso and Cote d'Ivoire. To this aim, we used mosquito field collections along with heterogeneous, multisource and multi-scale environmental data. The objectives were i) to assess the small-scale spatial and temporal heterogeneity of the indicators, ii) to better understand their drivers, and iii) to assess their spatio-temporal predictability, at scales that are consistent with operational action. The explanatory variables covered a wide range of potential environmental determinants of vector resistance to insecticide or feeding behaviour : vector control, human availability and nocturnal behaviour, macro and micro-climatic conditions, landscape, etc. The resulting models revealed many statistically significant associations, although their predictive powers were overall weak. We interpreted and discussed these associations in light of several topics of interest, such as : respective contribution of public health and agriculture in the development of physiological resistances, biological costs associated with physiological resistances, biological mechanisms underlying biting behavior, and impact of micro-climatic conditions on the time or place of biting. To our knowledge, our work is the first studying insecticide resistance and feeding behaviour of malaria vectors at such fine spatial scale with such a large dataset of both mosquito and environmental data.

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“…4 (2024), article e11 https://doi.org/10.24072/pcjournal.367 a kdr-e resistant allele significantly increased with both the time since LLIN distribution (up to 12 months after distribution) and the % of LLIN users in the village population. PermaNet 2.0 LLINs have been shown to retain their insecticidal efficacy under field conditions for at least one year after distribution (Djènontin et al, 2023;Kayedi et al, 2017;Kilian et al, 2008;Tan et al, 2016), exerting high selective pressure on vectors over this period at least. In contrast, there was no significant association between any of the target-site mutations and any of the crop-related variable.…”

Section: Associations With Variables Encoding Meteorological Conditio...mentioning

confidence: 99%

Physiological and behavioural resistance of malaria vectors in rural West-Africa: a data mining study to address their fine-scale spatiotemporal heterogeneity, drivers, and predictability

Taconet,

Soma,

Zogo

et al. 2024

Peer Community Journal

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Insecticide resistance and behavioural adaptation of malaria mosquitoes affect the efficacy of longlasting insecticide nets -currently the main tool for malaria vector control. To develop and deploy complementary, efficient and cost-effective control interventions, a good understanding of the drivers of these physiological and behavioural traits is needed. In this data-mining exercise, we modelled a set of indicators of physiological resistance to insecticide (prevalence of three target-site mutations) and behavioural resistance phenotypes (early-and late-biting, exophagy) of anopheles mosquitoes in two rural areas of West-Africa, located in Burkina Faso and Cote d'Ivoire. To this aim, we used mosquito field collections along with heterogeneous, multi-source and multi-scale environmental data. The objectives were i) to assess the small-scale spatial and temporal heterogeneity of physiological resistance to insecticide and behavioural resistance phenotypes, ii) to better understand their drivers, and iii) to assess their spatio-temporal predictability, at scales that are consistent with operational action. The explanatory variables covered a wide range of potential environmental determinants of vector resistance to insecticide or behavioural resistance phenotypes: vector control, human availability and nocturnal behaviour, macro and micro-climatic conditions, landscape, etc. The resulting models revealed many statistically significant associations, although their predictive powers were overall weak. We interpreted and discussed these associations in light of several topics of interest, such as: respective contribution of public health and agriculture in the selection of physiological resistances, biological costs associated with physiological resistances, biological mechanisms underlying biting behaviour, and impact of micro-climatic conditions on the time or place of biting. To our knowledge, our work is the first modeling insecticide resistance and feeding behaviour of malaria vectors at such fine spatial scale with such a large dataset of both mosquito and environmental data.

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Short and long term evaluation of the efficiency of PermaNet® 2.0 bed net against environmental factors and washing using bioassay tests

Cited by 3 publications

References 20 publications

Evaluation of the durability and use of long‐lasting insecticidal nets in Nicaragua

Evaluation of the durability and use of long‐lasting insecticidal nets in Nicaragua

Physiological and behavioural resistance of malaria vectors in rural West-Africa : a data mining study to address their fine-scale spatiotemporal heterogeneity, drivers, and predictability

Physiological and behavioural resistance of malaria vectors in rural West-Africa: a data mining study to address their fine-scale spatiotemporal heterogeneity, drivers, and predictability

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