The impact of biosecurity and partial depopulation on Campylobacter prevalence in Irish broiler flocks with differing levels of hygiene and economic performance

Figures & data

Table 1 Odds ratios and 95% confidence intervals (CIs) for Campylobacter positivity on farms with and without specific biosecurity criteria at first thin

Criteria	High-performance farms odds ratio (95% CI)	Number of high-performance farms with factor/without factor	Low-performance farms odds ratio (95% CI)	Number of low-performance farms with factor/without factor
Biosecurity signage on farm	fc	12/0	fc	11/0
Defined concrete pathways	0.66 (0.25–1.76)	6/6	1.55 (0.49–4.87)	5/6
Physical step-over barrier	0.27 (0.06–1.19)	10/2	0.17 (0.04–0.66)^a	2/9
Concrete apron	fc	12/0	2.00 (0.64–6.23)	6/5
Disinfectant foot dip on farm	fc	12/0	fc	10/1
Hygiene facilities in good working condition	fc	12/0	fc	10/1
House-specific tools for maintenance	0.83 (0.25–2.82)	3/9	2.30 (0.73–7.25)	7/4
House-specific footwear	fc	12/0	0.13 (0.03–0.46)^a	5/6
House-specific disposable clothing	0.63 (0.08–4.72)	11/1	2.04 (0.66–6.30)	6/5
Vermin-proof bins to store dead birds	1.33 (0.3–5.85)	10/2	1.68 (0.50–5.68)	8/3
Sanitised water supply on farm	0.63 (0.04–10.59)	11/1	0.00 (0–0)	10/1
Rodent baiting undertaken	fc	12/0	2.42 (0.56–10.36)	9/2
House inlets secured against rodents with mesh	3.91 (0.78–19.46)	10/2	1.68 (0.50–5.68)	8/3
Fly screens used on farm	nc	0/12	nc	0/11
Proper House maintenance (free of cracks, leaks, draughts)	0.63 (0.08–4.72)	11/1	1.24 (0.33–4.60)	9/2
Six-metre gravel strip, free of vegetation down sides of all houses on farm	0.44 (0.16–1.24)	8/4	0.56 (0.18–1.71)	6/5
Perimeter fence at least 2 m high enclosing farm	1.84 (0.69–4.89)	6/6	2.67 (0.83–8.54)	8/3
Additional livestock kept on farm	2.5 (0.48–13.06)	10/2	0.16 (0.02–1.43)	9/2
Farms with additional livestock have separate access areas	fc	10/2	0.71 (0.23–2.22)	4/7
Storage of manure off site	fc	12/0	0.50 (0.09–2.76)	9/2
Absence of a water body within 0.5 km of farm (lakes/streams)	2.63 (0.88–7.84)	8/4	0.13 (0.03–0.53)^a	6/5
Presence of dog/cat/other pets on farm	2.88 (1.03–8.02)	7/5	2.31 (0.74–7.18)	6/5
Two or more broiler houses on farm	0.46 (0.17–1.29)	6/6	0.16 (0.04–0.60)^a	6/5

fc (full compliance): odds ratio cannot be calculated as all farms within sample population met criteria.

nc (non-compliance): odds ratio cannot be calculated as all farms within sample population did not met criteria.

^aThe odds of Campylobacter infection are significantly lower (P < 0.05) in farms that meet the criteria compared to farms that do not within the high- and low-performance populations.

Fig. 1 Comparisons of Campylobacter prevalence between high- and low-performance farms at a first and b final thin.

Fig. 2 Comparisons of Campylobacter prevalence between first and final thin in a high- and b low-performance farms.

Fig. 3 Comparisons of mean maximum (Max.) and minimum (Min.) temperatures by month.