Abstract
During the interval, corresponding with the incubation period in man, between intranasal inoculation of poliomyelitic virus in the monkey and the onset of spinal symptoms, the localizations of the virus are, with one exception, unknown. The exception is the olfactory bulb, where Flexner and Clark 1 found virus 48 hours after application to the nasal mucosa. At that time none was demonstrable in the medulla or spinal cord. In the present study, Macacus rhesus monkeys were given 3 intranasal instillations, without trauma, of active MV virus at intervals of 3 hours, or within a total period of about 6 hours. Monkeys so treated were sacrificed on the third, fourth, fifth, sixth, and seventh days, respectively. Brain and spinal cord were removed under aseptic precautions. Specimens were removed from various parts of the central nervous system, ground and suspended in physiological salt solution to approximate 10% concentration and injected intracerebrally in monkeys in 1.5-2.0 cc. amounts. These animals were observed for the appearance of the usual signs of poliomyelitis and, if positive, were examined postmortem for gross and histological lesions.
The efficacy of the intranasal method of inoculation employed was shown by a series of 26 monkeys used in a separate study (unpublished) by Schultz and Gebhardt, in which 23, or 88%, developed typical poliomyelitis. The average incubation period in these was 8.2 days (minimum, 7 days; maximum, 10 days).
The results follow:
Three days'incubation: no virus in left olfactory bulb, left thalamus, medulla, cervical and lumbar cord (pooled), cervical and lumbar intervertebral ganglia (pooled). (6 monkeys.)
Four days'incubation: virus in left olfactory bulb; no virus in hippocampus, left hypothalamus, medulla, cervical and lumbar cord and intervertebral ganglia (pooled). (6 monkeys.)
Seven days' incubation: virus in left olfactory bulb, right olfactory bulb, hippocampus.
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