Proceedings of the 10th International Colloquium on Paratuberculosis

separately for each existing herd <strong>of</strong> cattle in Sweden and was based on <strong>the</strong> type <strong>of</strong> herd and
<strong>the</strong> actual number <strong>of</strong> individuals included in a specific surveillance activity. The numbers <strong>of</strong>
herds and animals included for 2008 are presented in Table 1.
Table 1. Numbers <strong>of</strong> examined herds and animals within each surveillance component
covering paratuberculosis in Swedish cattle in 2008.
Surveillance component Number <strong>of</strong> herds
Number <strong>of</strong> individuals (>2
years)
imported domestic
Fallen stock 8698 3 31371
Surveillance programme 233 42 3198
Clinical surveillance 23994 213 702495
The study includes <strong>the</strong> main surveillance activities as regards paratuberculosis in Swedish
cattle (i.e. both dairy and beef). For <strong>the</strong> scenario-tree model, <strong>the</strong>se were categorized into <strong>the</strong>
following surveillance system components (SSCs): 1. Fallen stock necropsies, 2. Screening
<strong>of</strong> herds with imported animals, 3. Surveys <strong>of</strong> dairy herds, 4. Voluntary surveillance
programme in beef herds and 5. Clinical surveillance. The probability <strong>of</strong> freedom was
estimated for each year from 2005 to 2008 and <strong>the</strong> SSCs for each year are presented in Fig.
2. In order to account for <strong>the</strong> value <strong>of</strong> previous data, <strong>the</strong> probability <strong>of</strong> freedom at <strong>the</strong> end <strong>of</strong>
<strong>the</strong> study period was also estimated based on data from all years, 2005-2008. This time
period was chosen because <strong>the</strong> most recent case (one imported animal) was sampled in
2004, and enough detailed data were available for <strong>the</strong> entire period. The calculations were
made in one-year intervals, as illustrated in Fig. 2.
Figure 2. The surveillance components included for each year in <strong>the</strong> scenario-tree model <strong>of</strong>
MAP surveillance in Swedish cattle, 2005-2008.
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