To assess the influence of age on experimental infections,
we inoculated suckling voles intracerebrally with 750 ID50 Of
virus. Animals were examined daily for the first 5 weeks and
biweekly thereafter for signs of clinical illness and were
sacrificed 35 or 270 days postinoculation, at which time the
brain, lungs, kidneys, liver, heart, spleen, and salivary
glands were tested for antigen.