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An all-island approach to mapping bovine tuberculosis in Ireland.

McGrath G, Abernethy D, Stringer L, More S - Ir Vet J (2009)

Bottom Line: This is the first time that data pertaining to TB from the Republic of Ireland and Northern Ireland have been collated and examined in an all-Ireland context.The analyses were based on 198, 156 point locations representing active farms with cattle in Northern Ireland and the Republic of Ireland between the years 1996 and 2006.The results consist of a series of maps giving a visual representation of cattle populations and associated detected bTB levels on the island of Ireland over this time interval.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for Veterinary Epidemiology and Risk Analysis, Veterinary Sciences Centre, UCD School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland. guy.mcgrath@ucd.ie.

ABSTRACT
This study used techniques in Geographical Information Systems (GIS) to explore the spatial patterns of bovine tuberculosis (TB) in the whole island of Ireland over an 11-year period. This is the first time that data pertaining to TB from the Republic of Ireland and Northern Ireland have been collated and examined in an all-Ireland context. The analyses were based on 198, 156 point locations representing active farms with cattle in Northern Ireland and the Republic of Ireland between the years 1996 and 2006. The results consist of a series of maps giving a visual representation of cattle populations and associated detected bTB levels on the island of Ireland over this time interval.

No MeSH data available.


Related in: MedlinePlus

Density map of TB standard reactors detected each year on the island of Ireland for the years 1996 to 2006.
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Figure 2: Density map of TB standard reactors detected each year on the island of Ireland for the years 1996 to 2006.

Mentions: The first method involved transforming the point locations representing farms from Cartesian co-ordinates (X, Y) into a continuous surface. This technique is known as kernel smoothing and uses a bivariate probability density function (or kernel) to allocate a density distribution at each location, based on the selected bandwidth or search radius [5]. Two surfaces were generated for each year, one representing the number of animals tested (Figure 1) and the other the number of standard reactors (Figure 2). The output values for these surfaces were per square kilometre. The disease surface (standard reactors) was then divided by the population surface (number of animal tests) to create a relative risk surface for each year (Figure 3). This work was conducted using ArcGIS 9.1 (ESRI, Redlands, CA, USA). The reactor and population surfaces were separately generated (using the Spatial Analyst extension - kernel density) using a 15 kilometre search radius and a grid size of 250 metres. A 10 kilometre search radius was used for the enumerator raster surface to eliminate the edge effect associated with dividing raster surfaces of matching extents. Then, the relative risk surface was calculated (using 3D Analyst, Raster Math, Divide function), and the output surface was masked to a coverage of the coast of Ireland. The relative risk surface gives a better spatial representation of the disease than a surface generated from a point-based annual incidence map.


An all-island approach to mapping bovine tuberculosis in Ireland.

McGrath G, Abernethy D, Stringer L, More S - Ir Vet J (2009)

Density map of TB standard reactors detected each year on the island of Ireland for the years 1996 to 2006.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3113757&req=5

Figure 2: Density map of TB standard reactors detected each year on the island of Ireland for the years 1996 to 2006.
Mentions: The first method involved transforming the point locations representing farms from Cartesian co-ordinates (X, Y) into a continuous surface. This technique is known as kernel smoothing and uses a bivariate probability density function (or kernel) to allocate a density distribution at each location, based on the selected bandwidth or search radius [5]. Two surfaces were generated for each year, one representing the number of animals tested (Figure 1) and the other the number of standard reactors (Figure 2). The output values for these surfaces were per square kilometre. The disease surface (standard reactors) was then divided by the population surface (number of animal tests) to create a relative risk surface for each year (Figure 3). This work was conducted using ArcGIS 9.1 (ESRI, Redlands, CA, USA). The reactor and population surfaces were separately generated (using the Spatial Analyst extension - kernel density) using a 15 kilometre search radius and a grid size of 250 metres. A 10 kilometre search radius was used for the enumerator raster surface to eliminate the edge effect associated with dividing raster surfaces of matching extents. Then, the relative risk surface was calculated (using 3D Analyst, Raster Math, Divide function), and the output surface was masked to a coverage of the coast of Ireland. The relative risk surface gives a better spatial representation of the disease than a surface generated from a point-based annual incidence map.

Bottom Line: This is the first time that data pertaining to TB from the Republic of Ireland and Northern Ireland have been collated and examined in an all-Ireland context.The analyses were based on 198, 156 point locations representing active farms with cattle in Northern Ireland and the Republic of Ireland between the years 1996 and 2006.The results consist of a series of maps giving a visual representation of cattle populations and associated detected bTB levels on the island of Ireland over this time interval.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for Veterinary Epidemiology and Risk Analysis, Veterinary Sciences Centre, UCD School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland. guy.mcgrath@ucd.ie.

ABSTRACT
This study used techniques in Geographical Information Systems (GIS) to explore the spatial patterns of bovine tuberculosis (TB) in the whole island of Ireland over an 11-year period. This is the first time that data pertaining to TB from the Republic of Ireland and Northern Ireland have been collated and examined in an all-Ireland context. The analyses were based on 198, 156 point locations representing active farms with cattle in Northern Ireland and the Republic of Ireland between the years 1996 and 2006. The results consist of a series of maps giving a visual representation of cattle populations and associated detected bTB levels on the island of Ireland over this time interval.

No MeSH data available.


Related in: MedlinePlus