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An agent-based model of the population dynamics of Anopheles gambiae.

Arifin SM, Zhou Y, Davis GJ, Gentile JE, Madey GR, Collins FH - Malar. J. (2014)

Bottom Line: Results show that with varying coverage and temperature ranges, the hypothetical interventions targeting the gonotrophic cycle stages produce higher impacts than the rest in reducing the potentially infectious female (PIF) mosquito populations, due to their multi-hour mortality impacts and their applicability at multiple gonotrophic cycles.A combined HVCI with low coverage can produce additive synergistic impacts and can be more effective than isolated HVCIs with comparatively higher coverages.The utility of the core model has also been demonstrated by several other applications, each of which investigates well-defined biological research questions across a variety of dimensions (including spatial models, insecticide resistance, and sterile insect techniques).

View Article: PubMed Central - PubMed

Affiliation: Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, IN 46556, USA. niazarifin@gmail.com.

ABSTRACT

Background: Agent-based models (ABMs) have been used to model the behaviour of individual mosquitoes and other aspects of malaria. In this paper, a conceptual entomological model of the population dynamics of Anopheles gambiae and the agent-based implementations derived from it are described. Hypothetical vector control interventions (HVCIs) are implemented to target specific activities in the mosquito life cycle, and their impacts are evaluated.

Methods: The core model is described in terms of the complete An. gambiae mosquito life cycle. Primary features include the development and mortality rates in different aquatic and adult stages, the aquatic habitats and oviposition. The density- and age-dependent larval and adult mortality rates (vector senescence) allow the model to capture the age-dependent aspects of the mosquito biology. Details of hypothetical interventions are also described.

Results: Results show that with varying coverage and temperature ranges, the hypothetical interventions targeting the gonotrophic cycle stages produce higher impacts than the rest in reducing the potentially infectious female (PIF) mosquito populations, due to their multi-hour mortality impacts and their applicability at multiple gonotrophic cycles. Thus, these stages may be the most effective points of target for newly developed and novel interventions. A combined HVCI with low coverage can produce additive synergistic impacts and can be more effective than isolated HVCIs with comparatively higher coverages. It is emphasized that although the model described in this paper is designed specifically around the mosquito An. gambiae, it could effectively apply to many other major malaria vectors in the world (including the three most efficient nominal anopheline species An. gambiae, Anopheles coluzzii and Anopheles arabiensis) by incorporating a variety of factors (seasonality cycles, rainfall, humidity, etc.). Thus, the model can essentially be treated as a generic Anopheles model, offering an excellent framework for such extensions. The utility of the core model has also been demonstrated by several other applications, each of which investigates well-defined biological research questions across a variety of dimensions (including spatial models, insecticide resistance, and sterile insect techniques).

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Impact of varying coverage (C) on abundance and potentially infectious females, with hypothetical vector control interventions applied to multiple life cycle stages (IA, BMS, BMD, G). (a)-(b) and (c)-(d) depict abundance and PIF, respectively. (a) and (c) represent results for (IA, BMS, BMD, G)Entering; (b) and (d) represent results for (IA, BMS, BMD, G)Resting. Each colour-coded plot represents a specific coverage (C), with colour keys presented in the legend. Killing K and temperature (T) are fixed at 50% and 25°C, respectively. The x-axis denotes simulation time (in days), and the y-axis denotes abundance or PIF. HVCIs are applied on day 100, and continued up to the end of the simulation. The warm-up period is omitted from the results.
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Fig6: Impact of varying coverage (C) on abundance and potentially infectious females, with hypothetical vector control interventions applied to multiple life cycle stages (IA, BMS, BMD, G). (a)-(b) and (c)-(d) depict abundance and PIF, respectively. (a) and (c) represent results for (IA, BMS, BMD, G)Entering; (b) and (d) represent results for (IA, BMS, BMD, G)Resting. Each colour-coded plot represents a specific coverage (C), with colour keys presented in the legend. Killing K and temperature (T) are fixed at 50% and 25°C, respectively. The x-axis denotes simulation time (in days), and the y-axis denotes abundance or PIF. HVCIs are applied on day 100, and continued up to the end of the simulation. The warm-up period is omitted from the results.

Mentions: The impact of two HVCIs targeting multiple adult life cycle stages with varying coverage is shown in Figure 6. Note that these HVCIs essentially represent sugar meal traps (that assumes a daily sugar meal by female mosquitoes). Figure 6a and c represent results for (IA, BMS, BMD, G)Entering, and Figure 6b and d represent results for (IA, BMS, BMD, G)Resting. Killing K and temperature T are fixed at 50% and 25°C, respectively. As shown in Figure 6a and c, with moderate levels (50%) of coverage and killing, (IA, BMS, BMD, G)Entering can produce considerable impacts on both abundance and PIF, and performs better than BMSForaging and BMDResting (compare to Figure 3b and e). However, as the coverage rises up to 75%, the PIF populations die off, as shown in Figure 6c. Although (IA, BMS, BMD, G)Entering places a one-time hazard in each of the four adult stages, it can eliminate the PIF population, because the last three stages (BMS, BMD, G) are the gonotrophic cycle stages, implying impacts during each stage occurring over multiple gonotrophic cycles. Another configuration of C =50%, K =75%, having the same products of the two parameters, produce similar impact on the outputs.Figure 6


An agent-based model of the population dynamics of Anopheles gambiae.

Arifin SM, Zhou Y, Davis GJ, Gentile JE, Madey GR, Collins FH - Malar. J. (2014)

Impact of varying coverage (C) on abundance and potentially infectious females, with hypothetical vector control interventions applied to multiple life cycle stages (IA, BMS, BMD, G). (a)-(b) and (c)-(d) depict abundance and PIF, respectively. (a) and (c) represent results for (IA, BMS, BMD, G)Entering; (b) and (d) represent results for (IA, BMS, BMD, G)Resting. Each colour-coded plot represents a specific coverage (C), with colour keys presented in the legend. Killing K and temperature (T) are fixed at 50% and 25°C, respectively. The x-axis denotes simulation time (in days), and the y-axis denotes abundance or PIF. HVCIs are applied on day 100, and continued up to the end of the simulation. The warm-up period is omitted from the results.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4233045&req=5

Fig6: Impact of varying coverage (C) on abundance and potentially infectious females, with hypothetical vector control interventions applied to multiple life cycle stages (IA, BMS, BMD, G). (a)-(b) and (c)-(d) depict abundance and PIF, respectively. (a) and (c) represent results for (IA, BMS, BMD, G)Entering; (b) and (d) represent results for (IA, BMS, BMD, G)Resting. Each colour-coded plot represents a specific coverage (C), with colour keys presented in the legend. Killing K and temperature (T) are fixed at 50% and 25°C, respectively. The x-axis denotes simulation time (in days), and the y-axis denotes abundance or PIF. HVCIs are applied on day 100, and continued up to the end of the simulation. The warm-up period is omitted from the results.
Mentions: The impact of two HVCIs targeting multiple adult life cycle stages with varying coverage is shown in Figure 6. Note that these HVCIs essentially represent sugar meal traps (that assumes a daily sugar meal by female mosquitoes). Figure 6a and c represent results for (IA, BMS, BMD, G)Entering, and Figure 6b and d represent results for (IA, BMS, BMD, G)Resting. Killing K and temperature T are fixed at 50% and 25°C, respectively. As shown in Figure 6a and c, with moderate levels (50%) of coverage and killing, (IA, BMS, BMD, G)Entering can produce considerable impacts on both abundance and PIF, and performs better than BMSForaging and BMDResting (compare to Figure 3b and e). However, as the coverage rises up to 75%, the PIF populations die off, as shown in Figure 6c. Although (IA, BMS, BMD, G)Entering places a one-time hazard in each of the four adult stages, it can eliminate the PIF population, because the last three stages (BMS, BMD, G) are the gonotrophic cycle stages, implying impacts during each stage occurring over multiple gonotrophic cycles. Another configuration of C =50%, K =75%, having the same products of the two parameters, produce similar impact on the outputs.Figure 6

Bottom Line: Results show that with varying coverage and temperature ranges, the hypothetical interventions targeting the gonotrophic cycle stages produce higher impacts than the rest in reducing the potentially infectious female (PIF) mosquito populations, due to their multi-hour mortality impacts and their applicability at multiple gonotrophic cycles.A combined HVCI with low coverage can produce additive synergistic impacts and can be more effective than isolated HVCIs with comparatively higher coverages.The utility of the core model has also been demonstrated by several other applications, each of which investigates well-defined biological research questions across a variety of dimensions (including spatial models, insecticide resistance, and sterile insect techniques).

View Article: PubMed Central - PubMed

Affiliation: Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, IN 46556, USA. niazarifin@gmail.com.

ABSTRACT

Background: Agent-based models (ABMs) have been used to model the behaviour of individual mosquitoes and other aspects of malaria. In this paper, a conceptual entomological model of the population dynamics of Anopheles gambiae and the agent-based implementations derived from it are described. Hypothetical vector control interventions (HVCIs) are implemented to target specific activities in the mosquito life cycle, and their impacts are evaluated.

Methods: The core model is described in terms of the complete An. gambiae mosquito life cycle. Primary features include the development and mortality rates in different aquatic and adult stages, the aquatic habitats and oviposition. The density- and age-dependent larval and adult mortality rates (vector senescence) allow the model to capture the age-dependent aspects of the mosquito biology. Details of hypothetical interventions are also described.

Results: Results show that with varying coverage and temperature ranges, the hypothetical interventions targeting the gonotrophic cycle stages produce higher impacts than the rest in reducing the potentially infectious female (PIF) mosquito populations, due to their multi-hour mortality impacts and their applicability at multiple gonotrophic cycles. Thus, these stages may be the most effective points of target for newly developed and novel interventions. A combined HVCI with low coverage can produce additive synergistic impacts and can be more effective than isolated HVCIs with comparatively higher coverages. It is emphasized that although the model described in this paper is designed specifically around the mosquito An. gambiae, it could effectively apply to many other major malaria vectors in the world (including the three most efficient nominal anopheline species An. gambiae, Anopheles coluzzii and Anopheles arabiensis) by incorporating a variety of factors (seasonality cycles, rainfall, humidity, etc.). Thus, the model can essentially be treated as a generic Anopheles model, offering an excellent framework for such extensions. The utility of the core model has also been demonstrated by several other applications, each of which investigates well-defined biological research questions across a variety of dimensions (including spatial models, insecticide resistance, and sterile insect techniques).

Show MeSH
Related in: MedlinePlus