Table 3 Mean PRRSv PCR treshold cycle (Ct) values for different samples collected from farrowed piglets in the PRRSV challenge study in pregnant sows. Samples were collected on different days post challenge and days post-farrow. Values equal or higher than 37 were considered as not detected (nd) and are not included in the calculation of the mean Ct values. Values between brackets indicate the ratio of positive samples by total number of samples

Faecal swab

Untreated-unchallenged

nd

(0/95)

nd

(0/70)

nd

(0/64)

nd

(0/63)

nd

(0/61)

Untreated-challenged

33.3

(14/41)

30.9

(29/29)

30.6

(10/10)

35.5

(7/8)

33.9

(3/8)

Treated-challenged^a

34.0

(19/36)

31.5

(26/28)

30.4

(12/13)

32.8

(5/5)

nd

(0/9)

Oral swab

Untreated-unchallenged

nd

(0/95)

nd

(0/70)

nd

(0/64)

nd

(0/63)

nd

(0/60)

Untreated-challenged

35.2

(12/41)

32.5

(21/29)

34.9

(6/10)

33.2

(4/8)

34.5

(3/8)

Treated-challenged^a

34.2.

(23/36)

34.4

(18/28)

33.1

(10/13)

34.6

(7/10)

35.8

(2/10)

Blood serum

Untreated-unchallenged

nd

(0/93)

nd

(0/69)

nd

(0/64)

nd

(0/62)

nd

(0/60)

Untreated-challenged

22.3

(36/41)

16.0

(28/28)

17.1

(10/10)

19.2

(7/7)

23.8

(8/8)

Treated-challenged^a

19.7.

(34/35)

16.7

(28/28)

16.0

(13/13)

18.1

(10/11)

24.0

(9/9)