Plastic vial

To collect oral fluids, a cotton triple-stranded rope (TD PROMT LLC, Lipetsk, Russia) was suspended in a pen in front of each animal at shoulder height for 20–30 min for chewing. For this period of time the animals were kept individually. The pigs chewed on the ropes, and after that the oral fluids were collected individually by cutting off the wet end of the rope and putting it into a plastic bag (TD PROMT LLC, Lipetsk, Russia). Then the liquid was squeezed into a plastic vial (Fisher Scientific Company LLC, Pittsburgh, PA, USA) and centrifuged at 1200× g for 2 min. The supernatant was collected for testing. Sera and whole blood samples were obtained by jugular venipuncture. To obtain whole blood, the blood samples were collected in EDTA tubes (TD VIK LLC, Lyubertsy, Russia), and to obtain blood serum, the whole blood was collected in serum tubes (TD VIK LLC, Lyubertsy, Russia), allowed to clot, and then centrifuged for 10 min at 2000× g. Three aliquots of all the samples described above were prepared and stored in 5 mL or 2 mL cryovials at minus 40 °C until testing (Corning Inc., Corning, NY, USA). All equipment used for sampling was cleaned and disinfected between pigs and uses. All samples were frozen and thawed once prior to the test.

To collect oral fluids, a cotton triple-stranded rope (TD PROMT LLC, Lipetsk, Russia) was suspended in a pen in front of each animal at shoulder height for 20–30 min for chewing. For this period of time the animals were kept individually. The pigs chewed on the ropes, and after that the oral fluids were collected individually by cutting off the wet end of the rope and putting it into a plastic bag (TD PROMT LLC, Lipetsk, Russia). Then the liquid was squeezed into a plastic vial (Fisher Scientific Company LLC, Pittsburgh, PA, USA) and centrifuged at 1200× g for 2 min. The supernatant was collected for testing.
Sera and whole blood samples were obtained by jugular venipuncture. To obtain whole blood, the blood samples were collected in EDTA tubes (TD VIK LLC, Lyubertsy, Russia), and to obtain blood serum, the whole blood was collected in serum tubes (TD VIK LLC, Lyubertsy, Russia), allowed to clot, and then centrifuged for 10 min at 2000× g.
Three aliquots of all the samples described above were prepared and stored in 5-mL or 2-mL cryovials at minus 40 °C until testing (Simport Scientific, Saint-Mathieu-de-Beloeil, QC, Canada) (Corning Inc, Corning, NY, USA). All equipment used for sampling was cleaned and disinfected between pigs and uses. All samples were frozen and thawed once prior to the test.