Table 1.

Composition of groups included in the study and conducted analyses

Group	PRRSV herd status	n	Origin of samples	PCR done
Group 1	Negative exposed	21	PRRSV vaccinated pigs	Yes
Group 2	Positive	49	Boars, Austria	Yes
		104	Fatteners, Austria	No
		80	Pigs, Russia	Yes, tissue
		12	Pigs, Southeast Asia	Yes
Group 3	Negative	153	Boars, Austria	No
		15	Sows, Germany	No
		141	Boars, Germany	No
Group 4	Suspected negative	256	Fatteners, Austria	No
Group 5	Unknown	92	Wild boars, Austria	No