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Appendix
The Prevalence of Polio-encephalo-myelitis in 1949
The prevalence of polio-myelitis in the Borough in 1949 commenced
on June 28th in a child age four living in Highgate. Up to the time of
writing this report, on September 5th, 28 notifications were received.
The last case occurred on August 14th, over three weeks ago, so that it
would appear that the prevalence has been checked for the time being,
and perhaps for this season
However, it must be borne in mind that the normal season of
poliomyelitis prevalence runs to the end of September and possibly into
October. It would appear that much depends on weather conditions.
A continuance of the dry warm summer into the autumn may mean a
recrudescence of the disease between now and October.
Four of the notifications turned out to be other conditions—
" teething," " tonsillitis," " osteo-myelitis" and " common cold."
Amongst the remaining twenty-four cases, five were polio-encephalitis
of the bulbar type in which the disease attacks the vital centres of respiration
and circulation in the brain. One of these was in a woman age 37,
and four in males ages 5, 6, 18, 25—all five proved fatal. Seven of the
cases showed no signs of paralysis at any stage of their illness, but the
diagnosis of poliomyelitis on clinical symptoms was supported by the
laboratory examination of the cerebro-spinal fluid obtained by lumbar
puncture. The most characteristic change in this fluid is increase in the
number of lymphocytes from 10 or fewer per cubic millimetre to perhaps
hundreds. This illness was therefore named " benign lymphocytic
meningitis." " Poliomyelitis without paralysis " is a better name because
there can be no doubt that it is produced by invasion of the central
nervous system by the same virus as that which causes paralytic poliomyelitis.
Moreover, it is possible that the number of cases of this mild
non-paralytic form of the disease is very much greater than the notifications
indicate. It has been suggested in some investigations of outbreaks
of polio-encephalo-myelitis that for every case showing paralysis there
may be ten to one hundred cases of "poliomyelitis without paralysis."
If this is an accurate scientific concept, then it follows that measures for
control of outbreaks of the disease are rendered ineffective by the immense
reservoir of infection prevailing during epidemic periods.
The remaining twelve notified cases showed some degree of paralysis
of one or more limbs. All of them are still under treatment in hospital
or are attending as out-patients after discharge from hospital. Progress
towards recovery is practically complete in many and in no case is the
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