Table 5.
Percentage of risk-based sampling components (n = 366) stratified by risk factor (95% confidence interval). Multiple selections of risk factors per components were allowed. The risk-based components were a subset of active surveillance components (n = 664) recorded by 10 study countries for the year 2011
| Risk factor | Percentage of components (95% CI) | Main type | Comments (remaining components either other type or unknown) |
|---|---|---|---|
| Production type | 45·1% (39·9–50.3) | Targeted | 142/165: Only breeding animals; 96/142: Surveillance in artificial insemination centres |
| Age | 24·3% (20.0–29·0) | Targeted | 36/89: Serological components targeting only older animals; 37/89: BSE/scrapie components targeting older animals only |
| Region | 13·1% (9·8–17·0) | Stratified | 27/48: Surveillance intensity depended on epidemiological situation in the region |
| Herd size | 11·2% (8·2–14·9) | Targeted | 37/41: Only large sized farms were targeted |
| Time period | 6·0% (3·8–9·0) | Varies | Restricted to high-risk period (e.g. demonstrate freedom at end of high-risk period) or different sampling intensity between seasons |
| Production for human consumption | 3·6% (1·9–6·0) | Targeted | |
| Farm factors | 3·8% (2·1–6·3) | Varies | 5/13: Targeting only outdoor farms |
| Species | 2·5% (1·1–4·6) | Varies | Since components were generally split by species, this risk factor was predominantly recorded for avian influenza (distinction between wild bird and waterfowl species) |
| Event | 2·2% (0.9–4·3) | Targeted | Testing prior to transport |
| Disease status of the herd | 2·2% (0.9–4·3) | Targeted | E.g. certified free herds vs. non-free herds |
| Trade | 1·1% (0.3–2·8) | Varies | Trade volume (e.g. out-degree movements) |
| Previous | 2·2% (0.9–4·3) | Stratified | Previous irregularities or positive findings |
| Various | 0.8% (0.2–2·4) | n.a. | |
| Unknown | 1·9% (0.8–3·9) | n.a. |
n.a., Not applicable.