Table 3.

Overview of collected samples in 17 control herds during the first and second herd visit

	Samples tested visit 1				Samples tested visit 2
	Milk		Nasal swabs		Milk		Nasal swabs
Control herd ID	No	PCR pos.	No	PCR pos.	No	PCR pos.	No	PCR pos.
1	21	0	1	0	21	0	0	0
2	40	0	3	0	42	0	4	0
3	7	0	2	1	7	0	1	0
4*	36	0	0	0	0	0	0	0
5*	30	0	8	0	0	0	0	0
6*	18	0	6	0	0	0	0	0
7	18	0	2	0	19	0	2	0
8*	60	0	0	0	0	0	0	0
9*	32	0	6	0	0	0	0	0
10	58	0	4	0	54	0	4	0
11	46	0	9	0	38	0	0	0
12*	49	0	0	0	0	0	0	0
13	57	0	5	0	50	0	2	0
14	16	0	4	0	18	0	4	0
15	10	0	3	0	9	0	2	0
16*	25	0	4	0	0	0	0	0
17*	28	0	5	0	0	0	0	0
total	551	0	62	1	258	0	19	0

*Herds were not visited a second time.