Table 1.

Incubation period of VRQ/VRQ TSE-free recipient sheep transfused with whole blood collected from three VRQ/VRQ sheep naturally contaminated with classical scrapie^a

Donor	Incubation period (days) at blood collection day:
	90	150	210	270	360	460	580	720
D1	736	792	867	834	719	703	724	557
D2	835	765	735	787	653	621	643	690
D3	912	812	767	750	693	689	709	653

^aBlood samples (180 ml) from three VRQ/VRQ donors (identified as D1, D2, and D3) born and raised in the INRA Langlade flock were drawn at different time points of the incubation phase. The three donors died at 781, 728, and 789 days of age, respectively. After death, natural scrapie occurrence was confirmed by histopathology (vacuolar changes in the central nervous system) and the detection of abnormal PrP deposits in the central nervous system and lymphoid tissues. Blood was transfused to TSE-free VRQ/VRQ recipients within 12 h following collection. Recipients were observed until the occurrence of clinical signs. The incubation periods in recipients are presented. In all recipients, abnormal PrP was detected in brain and lymphoid tissues after death.