View report page

16
Infectious
diseases
The attack rates and death rates of the principal infectious diseases in London
during 1949 and earlier years, and for the constituent metropolitan boroughs in
1949, are shown in Tables 2, 3 and 11. A comparison of the death-rates in London
and England and Wales is given in Table 10 (p. 125). In order to preserve uniformity
with national statistics the notification figures used in this section of the report have
been corrected as far as possible to take account of changes of diagnosis made after
the original notifications had been received. See footnote to Table 11.
Anthrax
Three cases of anthrax were notified during the year and they were all confirmed
bacteriologically. One case was a lorry driver employed in delivering sacks of fertiliser,
another was a rag sorter and the third was a fur dresser. Appropriate precautionary
action was taken by the responsible Medical Officers of Health of the metropolitan
boroughs concerned and no secondary infections occurred.
Cerebrospinal
fever
Prior to the war the attack rate for cerebro-spinal fever had fluctuated mainly
between 0.02 and 0.05 per 1,000. Not unexpectedly the rate rose during 1940-41 to
0.3 per 1,000, a similar rise being experienced by most of the combatant nations
coincidental with military and industrial mobilisation. Subsequently the rate fell
rapidly. In 1949 the incidence was only 0.023 per 1,000 (76 cases), the rate being the
lowest since before the 1914-18 War. The ratio of notifications to deaths was 4: 1,
but owing to imperfect notification the case fatality from the disease is less than
would appear from this ratio. Mortality is greatest at the extremes of age. Twothirds
of the cases were in infants under the age of five years.
Dysentery
The dysentery notifications are not at present an indication of the trend of
incidence of the disease. The notification figures show capricious movement from
year to year. The fact that many cases of comparatively mild disease without any
of the classical signs and symptoms are due to dysenteric infection has become
increasingly recognised.

In 1948 there were, however, only three deaths compared with 11 in 1947, and
in 1949 there were only 4 deaths. There can be little doubt that the rise in incidence
with lowered fatality that began about 1935 was associated with increased recognition
of the comparatively mild Sonne infection. It is not known to what extent increased
incidence may be due to the increased awareness, and use, of Public Health
bacteriology.
Diphtheria
The campaign to encourage immunisation against diphtheria began in 1941 and
the results have been very encouraging. The fall in the incidence of diphtheria since
then has been far in excess of any downward fluctuation observed in the previous
50 years. In 1949 there were only 221 cases or 0.065 per 1,000 living, at all ages,
compared with a rate of 0.100 in 1948. 81 per cent. of the cases under age 15 were
among those who had never been immunised and having regard to the relative size
of the unimmunised population this means that the attack rate among them was ten
times as great as among those who had at some time been immunised. The effects
of the immunisation campaign are illustrated by the subjoined diagram, on which
the continuous lines indicate the trend of the notification rates in the three age
groups 0-4, 5-14, 15+-, and the broken line indicates the percentage not artificially