Oropharyngeal swab sampling for PRRSV detection in large-scale pig farms: a convenient and reliable method for mass sampling

Table 2 Detection of PRRSV in growing pigs under field condition

Sample types	30 days of age		70 days of age		110 days of age
Sample types	Positivity rate	Ct value Mean ± SD	Positivity rate	Ct value Mean ± SD	Positivity rate	Ct value Mean ± SD
OSs	3/20 15.0%^A	35.5 ± 1.3	20/20 100%^B	34.4 ± 2.0^a	10/18 55.6%^B	33.9 ± 1.8^a
NSs	0/20 0.0%^A	–	3/20 15.0%^A	33.2 ± 2.0^a	2/18 11.1%^A	36.1 ± 2.5^a
RSs	0/20 0.0%^A	–	4/20 20.0%^A	34.6 ± 1.6^a	4/18 22.2%^AB	37.5 ± 1.0^a
OFs	1/20 5%^A	36.5 ± 0	10/20 50.0%^A	35.9 ± 2.3^a	5/18 27.8%^AB	35.1 ± 3.1^a
Serum	1/20 5%^A	35.4 ± 0	10/20 50.0%^A	34.4 ± 2.5^a	6/18 33.3%^AB	31.8 ± 4.4^a

Different letters A, B and C indicate significant differences in PRRSV-positive proportions for samples. Mean values with letters a, b and c are with significant differences between different types of positive samples. Different letters indicate significant statistical differences (P < 0.05). The ‘–’ indicates that the samples were PRRSV negative
Oss oropharyngeal swabs; NSs nasal swabs; RSs rectal swabs; OFs oral fluid swabs

ISSN: 2055-5660