Table 1.

Data for experimental exposure groups and VLA scrapie flock cohorts.

Exposure Group	Birth cohort	Dam status	Area(s) exposed to	Length of time exposed to infected environment	Type of contact with VLA scrapie flock sheep	Number in group at start of exposure	Number of clinical cases	Median survival time (days)	Range survival time (days)
1	2003	N	None	N/A	None	7	0	-	-
2	2003	N	All	12 months	Direct	4	3*	792	747-792
3	2003	N	Lambing pens	6 weeks	Direct	6	4*	730	663-742
4	2003	N	Lambing pens	6 weeks	Indirect	6	5*	770	709-836
5	2002	A	All	6 weeks	Direct	5	5	659	639-857
6	2002	A	All	3 months	Direct	5	5	780	644-857
7	2002	A	All	12 months	Direct	5	5	728	716-775
8	2003	N	Pasture	6 weeks	Indirect	5	2	-	1094-1673
9	2003	N	Pasture	3 months	Indirect	5	4	1299	836-1299
10	2002	N	Pasture	12 months	Indirect	8	6*	794	729-869
11	2003	N	Pasture	6 weeks	Direct	5	5	817	728-1008
12	2003	N	Pasture	3 months	Direct	5	4*	776	684-791
13	2003	N	Pasture	12 months	Direct	5	5	807	742-823
VLA scrapie flock	2002	A	All	Birth to clinical endpoint	Direct	8	7*	709	592-730
VLA scrapie flock	2003	A	All	Birth to clinical endpoint	Direct	46	41*	748	601-1184

Dam status - N, naïve, TSE-free; A, scrapie affected.

* 'Number of clinical cases' is different to 'Number in group at start of exposure' due to intercurrent deaths.