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A case study of bovine tuberculosis in an area of County Donegal, Ireland.

Olea-Popelka F, Butler D, Lavin D, McGrath G, O'Keeffe J, Kelton D, Berke O, More S, Martin W - Ir Vet J (2006)

Bottom Line: Seventy two different herds were restricted for BTB during the FAP; 10 of these herds were restricted twice, resulting in a total of 82 BTB breakdowns.The analysis supports the hypothesis that BTB in herds is a problem that cannot be addressed successfully by dedicating our efforts to the elimination of single risk factors.Neither is it a problem that needs to be investigated only at the herd level, but rather at the area level, including groups of contiguous herds.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Population Medicine, Ontario Veterinary College, University of Guelph, Clinical Research Building, Guelph, Ontario, Canada N1G 2W1. olea@uoguelph.ca.

ABSTRACT
A descriptive analysis, to investigate the potential risk factors that might have contributed to the increased incidence of bovine tuberculosis (BTB) herd-breakdowns in the reference area of Co. Donegal during the fifth year of the four-area project (FAP), was performed. Seventy two different herds were restricted for BTB during the FAP; 10 of these herds were restricted twice, resulting in a total of 82 BTB breakdowns. During the first four years of the FAP, the number of BTB herd breakdowns in the area varied from a lowest of nine to a maximum of 18 per year, and were geographically dispersed. In the fifth year of the study a considerable increase in the number of BTB breakdowns (n = 32) was observed, and there was a spatial 'cluster' of infected herds in the eastern part of the study area. The increased number of BTB breakdowns during the fifth year most likely occurred because of the recrudescence of infection, herd-to-herd transmission and, to a lesser extent, purchase of infected cattle. Infected badgers remain as a possible but less likely source of infection, especially as an explanation for the cluster of infected herds. The analysis supports the hypothesis that BTB in herds is a problem that cannot be addressed successfully by dedicating our efforts to the elimination of single risk factors. Neither is it a problem that needs to be investigated only at the herd level, but rather at the area level, including groups of contiguous herds.

No MeSH data available.


Related in: MedlinePlus

Location of BTB 18 infected herds belonging to the cluster during the fifth year of the four-area project.
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Figure 3: Location of BTB 18 infected herds belonging to the cluster during the fifth year of the four-area project.

Mentions: The following discussion concerns the spatial cluster of 18 herds in the eastern section of the reference area; 12 denoted as group 2 herds (Table 2). With a herd size of 93, herd 'X' (Figure 3) held the largest number of animals in this cluster and the largest number (n = 17) of BTB-positive animals (reactors), including 16 standard reactors and nine animals with detected lesions. This herd had seven immediate neighbors, including five (71%) which were BTB-positive during year five; this cluster of six infected herds is referred to as group 3 herds (Table 2). Herd × was classified as BTB-positive on April 26, 2002 as part of a contiguous herd test (see below for details) because a neighbour's herd (herd 'E' in Figure 3) had a BTB breakdown, in a round test (in Ireland, this is the annual screening test for TB), 10 days prior to this date. The time-sequence and reason for testing herds around herd X that were identified as BTB-positive are shown in Figure 4. Before herd X was declared infected, four other neighbouring herds (referred to as herd 'A', 'B', 'C' and 'D' in Figures 3 and 4) were classified as BTB-positive. Herd A was the last BTB-positive herd identified during the fourth year of the FAP (August 30, 2001), one day before the fifth year began and 8.5 months before herd X was restricted. Herd A was identified as positive in a round test that disclosed one reactor and one standard reactor; both animals had BTB lesions at slaughter. Herds B, C and D were restricted in October 2001, January 2002 and February 2002, respectively (Figure 4 and Table 2).


A case study of bovine tuberculosis in an area of County Donegal, Ireland.

Olea-Popelka F, Butler D, Lavin D, McGrath G, O'Keeffe J, Kelton D, Berke O, More S, Martin W - Ir Vet J (2006)

Location of BTB 18 infected herds belonging to the cluster during the fifth year of the four-area project.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3113890&req=5

Figure 3: Location of BTB 18 infected herds belonging to the cluster during the fifth year of the four-area project.
Mentions: The following discussion concerns the spatial cluster of 18 herds in the eastern section of the reference area; 12 denoted as group 2 herds (Table 2). With a herd size of 93, herd 'X' (Figure 3) held the largest number of animals in this cluster and the largest number (n = 17) of BTB-positive animals (reactors), including 16 standard reactors and nine animals with detected lesions. This herd had seven immediate neighbors, including five (71%) which were BTB-positive during year five; this cluster of six infected herds is referred to as group 3 herds (Table 2). Herd × was classified as BTB-positive on April 26, 2002 as part of a contiguous herd test (see below for details) because a neighbour's herd (herd 'E' in Figure 3) had a BTB breakdown, in a round test (in Ireland, this is the annual screening test for TB), 10 days prior to this date. The time-sequence and reason for testing herds around herd X that were identified as BTB-positive are shown in Figure 4. Before herd X was declared infected, four other neighbouring herds (referred to as herd 'A', 'B', 'C' and 'D' in Figures 3 and 4) were classified as BTB-positive. Herd A was the last BTB-positive herd identified during the fourth year of the FAP (August 30, 2001), one day before the fifth year began and 8.5 months before herd X was restricted. Herd A was identified as positive in a round test that disclosed one reactor and one standard reactor; both animals had BTB lesions at slaughter. Herds B, C and D were restricted in October 2001, January 2002 and February 2002, respectively (Figure 4 and Table 2).

Bottom Line: Seventy two different herds were restricted for BTB during the FAP; 10 of these herds were restricted twice, resulting in a total of 82 BTB breakdowns.The analysis supports the hypothesis that BTB in herds is a problem that cannot be addressed successfully by dedicating our efforts to the elimination of single risk factors.Neither is it a problem that needs to be investigated only at the herd level, but rather at the area level, including groups of contiguous herds.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Population Medicine, Ontario Veterinary College, University of Guelph, Clinical Research Building, Guelph, Ontario, Canada N1G 2W1. olea@uoguelph.ca.

ABSTRACT
A descriptive analysis, to investigate the potential risk factors that might have contributed to the increased incidence of bovine tuberculosis (BTB) herd-breakdowns in the reference area of Co. Donegal during the fifth year of the four-area project (FAP), was performed. Seventy two different herds were restricted for BTB during the FAP; 10 of these herds were restricted twice, resulting in a total of 82 BTB breakdowns. During the first four years of the FAP, the number of BTB herd breakdowns in the area varied from a lowest of nine to a maximum of 18 per year, and were geographically dispersed. In the fifth year of the study a considerable increase in the number of BTB breakdowns (n = 32) was observed, and there was a spatial 'cluster' of infected herds in the eastern part of the study area. The increased number of BTB breakdowns during the fifth year most likely occurred because of the recrudescence of infection, herd-to-herd transmission and, to a lesser extent, purchase of infected cattle. Infected badgers remain as a possible but less likely source of infection, especially as an explanation for the cluster of infected herds. The analysis supports the hypothesis that BTB in herds is a problem that cannot be addressed successfully by dedicating our efforts to the elimination of single risk factors. Neither is it a problem that needs to be investigated only at the herd level, but rather at the area level, including groups of contiguous herds.

No MeSH data available.


Related in: MedlinePlus