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A spatial simulation model for the dispersal of the bluetongue vector Culicoides brevitarsis in Australia.

Kelso JK, Milne GJ - PLoS ONE (2014)

Bottom Line: Data from midge trapping programmes were used to qualitatively validate the resulting simulation model.This extended model could then be used as a platform for addressing the effectiveness of spatially targeted vaccination strategies or animal movement bans as BTV spread mitigation measures, or the impact of climate change on the risk and extent of outbreaks.These questions involving incursive Culicoides spread cannot be simply addressed with non-spatial models.

View Article: PubMed Central - PubMed

Affiliation: School of Computer Science and Software Engineering, University of Western Australia, Crawley, Western Australia, Australia.

ABSTRACT

Background: The spread of Bluetongue virus (BTV) among ruminants is caused by movement of infected host animals or by movement of infected Culicoides midges, the vector of BTV. Biologically plausible models of Culicoides dispersal are necessary for predicting the spread of BTV and are important for planning control and eradication strategies.

Methods: A spatially-explicit simulation model which captures the two underlying population mechanisms, population dynamics and movement, was developed using extensive data from a trapping program for C. brevitarsis on the east coast of Australia. A realistic midge flight sub-model was developed and the annual incursion and population establishment of C. brevitarsis was simulated. Data from the literature was used to parameterise the model.

Results: The model was shown to reproduce the spread of C. brevitarsis southwards along the east Australian coastline in spring, from an endemic population to the north. Such incursions were shown to be reliant on wind-dispersal; Culicoides midge active flight on its own was not capable of achieving known rates of southern spread, nor was re-emergence of southern populations due to overwintering larvae. Data from midge trapping programmes were used to qualitatively validate the resulting simulation model.

Conclusions: The model described in this paper is intended to form the vector component of an extended model that will also include BTV transmission. A model of midge movement and population dynamics has been developed in sufficient detail such that the extended model may be used to evaluate the timing and extent of BTV outbreaks. This extended model could then be used as a platform for addressing the effectiveness of spatially targeted vaccination strategies or animal movement bans as BTV spread mitigation measures, or the impact of climate change on the risk and extent of outbreaks. These questions involving incursive Culicoides spread cannot be simply addressed with non-spatial models.

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C. brevitarsis spread arrival times as determined by trapping experiments.Lines denote arrival times of C. brevitarsis derived from trapping data in New South Wales in 1991/2, classified by monthly zones. This figure is based on Figure 2 from [11]. Circles denote trapping site locations; filled circles indicate sites at which C. brevitarsis were detected, open circles where not detection occurred.
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pone-0104646-g005: C. brevitarsis spread arrival times as determined by trapping experiments.Lines denote arrival times of C. brevitarsis derived from trapping data in New South Wales in 1991/2, classified by monthly zones. This figure is based on Figure 2 from [11]. Circles denote trapping site locations; filled circles indicate sites at which C. brevitarsis were detected, open circles where not detection occurred.

Mentions: The northern coastal area of the region being considered in this study is pictured in the north-east corner of the map shown in Figure 5 and contains an endemic population of C. brevitarsis[11]. A viable population is known to persist throughout the mild winter period and subsequently increases as the weather warms during spring and summer [18]. This area is the source of midges which then spread southwards as the season progresses, as reported in the following [11], [16]–[19]. The area containing endemic midge populations was initialised by the simulation model using the population dynamics sub-model as follows.


A spatial simulation model for the dispersal of the bluetongue vector Culicoides brevitarsis in Australia.

Kelso JK, Milne GJ - PLoS ONE (2014)

C. brevitarsis spread arrival times as determined by trapping experiments.Lines denote arrival times of C. brevitarsis derived from trapping data in New South Wales in 1991/2, classified by monthly zones. This figure is based on Figure 2 from [11]. Circles denote trapping site locations; filled circles indicate sites at which C. brevitarsis were detected, open circles where not detection occurred.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126746&req=5

pone-0104646-g005: C. brevitarsis spread arrival times as determined by trapping experiments.Lines denote arrival times of C. brevitarsis derived from trapping data in New South Wales in 1991/2, classified by monthly zones. This figure is based on Figure 2 from [11]. Circles denote trapping site locations; filled circles indicate sites at which C. brevitarsis were detected, open circles where not detection occurred.
Mentions: The northern coastal area of the region being considered in this study is pictured in the north-east corner of the map shown in Figure 5 and contains an endemic population of C. brevitarsis[11]. A viable population is known to persist throughout the mild winter period and subsequently increases as the weather warms during spring and summer [18]. This area is the source of midges which then spread southwards as the season progresses, as reported in the following [11], [16]–[19]. The area containing endemic midge populations was initialised by the simulation model using the population dynamics sub-model as follows.

Bottom Line: Data from midge trapping programmes were used to qualitatively validate the resulting simulation model.This extended model could then be used as a platform for addressing the effectiveness of spatially targeted vaccination strategies or animal movement bans as BTV spread mitigation measures, or the impact of climate change on the risk and extent of outbreaks.These questions involving incursive Culicoides spread cannot be simply addressed with non-spatial models.

View Article: PubMed Central - PubMed

Affiliation: School of Computer Science and Software Engineering, University of Western Australia, Crawley, Western Australia, Australia.

ABSTRACT

Background: The spread of Bluetongue virus (BTV) among ruminants is caused by movement of infected host animals or by movement of infected Culicoides midges, the vector of BTV. Biologically plausible models of Culicoides dispersal are necessary for predicting the spread of BTV and are important for planning control and eradication strategies.

Methods: A spatially-explicit simulation model which captures the two underlying population mechanisms, population dynamics and movement, was developed using extensive data from a trapping program for C. brevitarsis on the east coast of Australia. A realistic midge flight sub-model was developed and the annual incursion and population establishment of C. brevitarsis was simulated. Data from the literature was used to parameterise the model.

Results: The model was shown to reproduce the spread of C. brevitarsis southwards along the east Australian coastline in spring, from an endemic population to the north. Such incursions were shown to be reliant on wind-dispersal; Culicoides midge active flight on its own was not capable of achieving known rates of southern spread, nor was re-emergence of southern populations due to overwintering larvae. Data from midge trapping programmes were used to qualitatively validate the resulting simulation model.

Conclusions: The model described in this paper is intended to form the vector component of an extended model that will also include BTV transmission. A model of midge movement and population dynamics has been developed in sufficient detail such that the extended model may be used to evaluate the timing and extent of BTV outbreaks. This extended model could then be used as a platform for addressing the effectiveness of spatially targeted vaccination strategies or animal movement bans as BTV spread mitigation measures, or the impact of climate change on the risk and extent of outbreaks. These questions involving incursive Culicoides spread cannot be simply addressed with non-spatial models.

Show MeSH
Related in: MedlinePlus