Table 1.

 Antibody responses in pigs directly inoculated with R1‐HK virus and in contact pigs

Assay	Number of serologically positive pigs and range of antibody titers (in parentheses)
	Directly inoculated pigs Days post inoculation			Contact pigs Days post contact
	0	14	28	0	14	28
HI (chicken RBC)	0 (<10)	6 (10–40)	6 (10–40)	0 (<10)	6 (10–40)	6 (10–40)
VN	0 (<2)	6 (24–64)	6 (12–64)	0 (<2)	6 (16–96)	6 (32–64)
NP‐ELISA	0 (≥0·6)	2 (0·565–0·508)	6 (0·584–0·445)	0 (≥0·6)	4 (0·529–0·427)	5 (0·524–0·377)
IPMA	0 (<5)	6 (1280–5120)	6 (1280–10240)	0 (<5)	6 (640–5120)	6 (1280–5120)

RBC, red blood cells.

The number of positive pigs among the total of six pigs is shown. Range of antibody titers in positive pigs are expressed as the reciprocal of the serum dilutions for virus neutralization, immunoperoxidase monolayer assay, and HI assays and as S/N ratio for the NP‐ELISA. S/N ratios ≥0·6 are considered negative.