TABLE 2.

Transmissibility of sheep scrapie to mice

Sheep	Mouse strain	Dead mice (n/N)a	PrPSc-positive mice (n′/N′)b	Mean time to death ± SD (day)
Scrapie
Sporadic
KH2	ICR	6/6	5/5	417 ± 29
KH2	I/LnJ	5/5	3/3	274, 275, 275, 275, 307d
KU	ICR	7/7	7/7	394 ± 672
SB	ICR	9/9	6/7	231, 451 ± 39e
Y2	ICR	5/5	4/4	418 ± 42
Y5	ICR	5/5	5/5	427 ± 15
Endemic
S1	ICR	1/6	1/6	359, >462f
S2	ICR	5/6	0/6	301, 400, 430, 478, 536, >620
S3	ICR	2/7	0/7	222, 413, >620
S3	I/LnJ	5/5	0/5	188, 200, 270, 363, 603g
Exptl
A1	ICR	6/6	6/6	229 ± 12
B3	ICR	7/7	7/7	236 ± 14
G1	ICR	9/9	8/9	190, 386 ± 20h
Healthy (S4)	ICR	0/4	NDc	>620

^aAbbreviations: n, number of animals which died of any cause during the observation period; N, number of animals which received brain homogenates.

^bAbbreviations: n′, number of PrP^Sc-positive mice; N′, number of mice used for the examination of PrP^Sc.

^cND, not determined.

^dAll the mice died of wounds received in violent fights without any symptoms of scrapie. The three mice which died at 275 dpi were found to be positive for PrP^Sc.

^eOne mouse which died at 231 dpi was negative for PrP^Sc. The mean and SD for time to death were calculated from data for the remaining eight mice.

^fOne mouse which died at 359 dpi did not show scrapie symptoms but was found to be positive for PrP^Sc.

^gFour mice died at 188, 200, 270, and 363 dpi due to fights.

^hOne mouse which died at 190 dpi was negative for PrP^Sc. The mean and SD for time to death was calculated from data for the remaining eight mice.