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32
DIPHTHERIA.

It has already been intimated that the actual number of cases recorded last year cannot be
compared with the figures of other years, owing to the fact that the statistical year 1913 included
53 weeks instead of the usual 52. In the case of diphtheria, another factor requires to be
considered when making comparisons either of recorded numbers or of the resulting morbidity
rates. The factor in question is the practice which has arisen during more recent years of
reporting "carrier" cases as "diphtheria." The Metropolitan Asylums Board's Hospitals are
intended for the reception of persons suffering from (among other diseases) diphtheria, i.e.,
persons acutely ill with the disease, which cannot be said to be the case with "carriers " The
Board distinguish in their Annual Reports between cases of clinical diphtheria and "carriers"
(described in the Reports as cases of " bacteriological diphtheria"). In 1910 the latter class
constituted 57 per cent, of all "diphtheria" cases admitted to the hospitals; in 1911, 66;
and in 1912, 7.1. It is probable that the proportion of "bacteriological" to all cases
of "diphtheria" notified is higher than that indicated above, as it is to be expected
that many cases notified are not sent to hospital on account of the absence of symptoms.
" Carrier" cases are undoubtedly sources of danger to the community, and it is desirable
that the sanitary authority should be kept informed of their occurrence; but, to enable
proper comparisons to be made year by year, or even between district and district,
provision should be made for the two classes to be distinguished in notification certificates,
the more so as the extent to which bacteriological tests are resorted and " carrier"
cases thereby discovered varies greatly in different districts. Having regard to the danger
to the community and to the difficulty of freeing the throat from the bacilli, the majority
of "carriers" require hospital isolation, and specially those "carrying" bacilli which are virulent.
It will be apparent later on that "carrier" cases helped very considerably last year to swell the
number of notifications of diphtheria.
The total of 296 cases recorded last year included 64 in two institutions, viz., the Infirmary
(55 cases) and the Orphanage of Mercy (9 cases), which, for reasons to be set out later, it is
thought should be excluded from the general figures for the Borough. The effect of such exclusion
on the morbidity rates of the several Wards is shown in the appended statement. The
adjusted rate for the Borough—i.e., the rate due to the prevalence of the disease among the
general population—vvas l-60 per 1,000, as compared with a recorded rate of 2'05 and an
average of 1T9, showing an increase of 34 per cent. The greatest increase in prevalence was
recorded in Westbourne Ward.

Among the 232 cases notified from the general population there were 33 in which the
original diagnosis of diphtheria was not confirmed, the total number of "errors" in the 296
reported cases being 37, or 12.5 per cent. of the notifications. In 1912 the proportion was 6.0