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56
XV.—INFECTIOUS DISEASES CONTROL.
Scarlet Fever.
One hundred and fifty-five rases were notified during
the year, equivalent to 3.2 per 1,000 population. Six
were over the age of 18 years.
The crest of the periodic wave of incidence was
reached in 1931. The fall in yearly incidence since was
continued with a slight rise in 1933, due to prevalence of
scarlet fever in the surrounding areas. It is rather
noteworthy that 59 per cent, of cases (92 in all) occurred
in the Downham area where there is frequent intercommunication
with friends in other areas where scarlet
fever has been prevalent. This fact is experienced in
practically all large and new housing estates.
Of the 155 cases notified 85 per cent, were admitted
to hospital and only 15 per cent, were home nursed. It
is well established knowledge that the sending of patients
to hospital does not control the incidence of scarlet fever,
and that mild cases of the infection may safely be isolated
at home. I have endeavoured to encourage this policy in
past years, but in spite of this no less than 85 per cent,
were admitted to hospital in 1933.
The 155 cases occurred in 113 families; 23 families
(65 patients in all) having more than one case per family.
In 16 of these families the secondary cases arose within
10 days of the first case being sent to hospital. In seven
families the second case arose within 20 days after the
return of first patients from isolation (the average period
of detention in hospital is 57.5 days) and these may be
taken as return cases.
The infectivity of a patient is not controllable by
practical means and in spite of every possible care being
taken before discharge of the patient from isolation, it is
found that certain cases are period)caJly infectious to other
persons even months after discharge from hospital. This
raises the question as to whether hospital detention
increases the infectivity of the causal organism, but on
this authoritative opinion varies. It is of interest to note
that in one of the 22 home nursed cases in 1933 a second