TABLE 1.

Mean time to death, clinical symptoms, and appearance of infected cells in mice inoculated experimentally with PrV-Ka and PrV-ΔUL51F

Parameter	Virus
	PrV-Ka	PrV-ΔUL51F
Mean time to death (h)a	50.0 (1.9)	64 (2.1)
Clinical symptoms (days p.i.)b
1	0	0
2	+++	+
3	†	+++
Immunohistochemistry (days p.i.)c
Nasal cavity	1	1
First-order neurons	1	2
Second-order neurons	2	3
Third-order neurons	−d	−

^aAverages calculated for 10 animals each. Standard deviations are indicated in parentheses.

^bClinical symptoms were measured as follows: 0, clinically normal mice; +, slight depression, hunched position, ruffled hair coat; ++, apathy, anorexia, moderate dyspnea, slight facial pruritus; +++, severe attacks of excitation, self-mutilation, skin erosions, heavy dyspnea; †, animals moribund or dead.

^cImmunohistochemistry was measured as the time in days p.i. of first antigen detection at the following different neuronal levels of the trigeminal pathway: nasal cavity in respiratory mucosal epithelium, first-order neurons in the trigeminal ganglion, second-order neurons in the spinal trigeminal nucleus (Sp5), and third-order neurons in the ectorhinal cortex.

^d−, no infected cells detectable.