Transmission of influenza A virus and porcine reproductive and respiratory syndrome virus using a novel nurse sow model: a proof of concept

Table 1 Influenza A virus reverse transcription polymerase chain reaction (rRT-PCR) and virus isolation (VI) results from sows and litters before and after adoption

Days post-adoption (litter age in days)	Activities	Test	Sow 1			Sow 2
Days post-adoption (litter age in days)	Activities	Test	Sow nasal swab^a	Udder wipe	Litter (POS/TOT)	Sow nasal swab	Udder wipe	Litter (POS/TOT)
− 8 (5)	Pre-challenge IAV status confirmation	rRT-PCR VI	NEG NT	NEG NT	0/12 NT	NEG NT	NEG NT	0/13 NT
− 7 (6)	1st IAV challenge of Sow 1 and half of her litter	rRT-PCR VI	NC NC	NC NC	NC NC	NC NC	NC NC	NC NC
− 6		rRT-PCR VI	21 NT	26.95 NT	6/6 NT	NEG NT	NEG NT	0/19 NT
− 5		rRT-PCR VI	22.92 NT	23.73 NT	6/6 NT	NEG NT	NEG NT	0/19 NT
− 4		rRT-PCR VI	30.02 NT	32.49 NT	6/6 NT	NC NC	NC NC	NC NC
− 3 (10)	2nd IAV challenge of Sow 1 and the rest of her litter	rRT-PCR VI	24.59 NT	29.13 NT	NC NC	NC NC	NC NC	NC NC
− 2^b		rRT-PCR VI	23 POS	24.24 NEG	11/12 NT	NEG NT	NEG NT	0/8 NT
− 1		rRT-PCR VI	28.22 NEG	26.79 POS	12/12 NT	NEG NT	NEG NT	0/8 NT
0 (13)	Adoption^b	rRT-PCR VI	NC NC	NC NC	NC NC	NC NC	NC NC	NC NC
1		rRT-PCR VI	30.71 NEG	35.21 NEG	1./8^b NT	34.83 NEG	23.81 POS	8/12 (2/2)^c NT
2		rRT-PCR VI	27.13 NEG	28.01 POS	6./8 NT	26.26 NT	21.18 POS	11/12 (2/2) NT
3		rRT-PCR VI	38.56 NEG	26.04 POS	5./8 NT	30.28 POS	22.16 POS	9/12 (2/2) NT
4		rRT-PCR VI	NC NC	30.69 NEG	8./8 NT	NC NC	NC NC	NC NC
5 (18)	End of IAV study	rRT-PCR VI	NC NC	29.79 NEG	8./8 NT	NC NC	NC NC	NC NC

At time of adoption litters were 13 days of age.
NC not collected, NT not tested.
^aNumber indicates rRT-PCR cycle threshold value.
^bNote that on adoption day and thereafter litter results correspond to the newly adopted piglets that originally belonged to the other sow.
^cIn parenthesis, results from in contact pigs after cross-fostering.

ISSN: 1297-9716