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is practically unknown in the under-developed countries of the
world and the inhabitants of those countries show a high level
of protective antibodies in their blood. This state of affairs
almost certainly arises from repeated sub-clinical infections
in infancy which confer a life-long immunity on the individual.
In those countries with a higher standard of living infants and
children are not exposed to these repeated infections with the
result that when poliomyelitis is introduced into a community
they have no protection. To give the necessary protection the
campaign for inoculation against poliomyelitis was launched
during the year. The immunisation is effected by injecting a
preparation of the killed virus into the child so as to provoke
the production of antibodies. At present nobody knows how long
the immunity will last. The campaign got off to a rather slow
start owing to technical difficulties in production and the
imposition of rigid safety precautions to see that no live virus
is present in the inoculum.
During the year there were 15 notifications of poliomyelitis
of which 9 were paralytic. One boy of five died.
Food poisoning
In all, 60 notificationsof food poisoning were received during
the year. 9 were notified in the first quarter, 31 in the second,
11 in thethird, and 9 in the fourth. There were 47 single cases
in 12 of whom the cause was found to be an organism of the
salmonella group. In the remaining 35 cases, the organism was
unidentified.
There was one outbreak in an institution involving 13
individuals, and was thought to have been caused by some mince.
Unfortunately a sample of the mince was not available by the
time symptoms occurred, but the recovery of an organism, CI.
welchii,from the stools of some of the patients suggested that
this was the bacterial agent responsible.
Dysentery.
This disease has become more prevalent in recent years, and
is almost always due to an organism known as Shigella sonne.
It is not usually serious except in infants and old persons.
During theyear 303 cases were notified, more than two-thirds of
them in the first half of the year, when it was particularly
prevalent in day nurseries. The co-operation of the Public
Health Staff of the London County Council was enlisted, and
eventually the outbreak was brought under control, although the
source was not definitely traced.