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12
ENTERIC FEVER.
"errors," and in the next quinquennium the annual average (15) included five "errors."
Expressed as percentages the "errors" formed 19.7 per cent. of all reported cases during
1909-13 and 19.5 during 1914-18.
After adjustment for such errors the cases of enteric fever averaged 23 in the quinquennium
1909-13 and 10 during 1914-18, as compared with eight in 1919 and 15 in 1920. The Index
Numbers (average 1909-13 = 100) are
1914-18 43; 1919 35; and 1920 65.
If the average for the "war period" be taken as a standard, the Numbers are
1909-13 230 ; 1919 80 ; and 1920 150.
Bacteriological Verification.—During 1919 in five instances—out of 10 reported cases—
resort was had to bacteriological tests, two of the tests yielding negative results. The negative
tests were yielded by patients whose cases were clinically diagnosed as "enteric fever," such
cases not constituting "errors.' In 1920, in 11 out of the 19 reported cases use was made of
bacteriology, all the tests proving positive. As regards the four "errors'' recorded in that year,
in one a positive reaction was obtained, but that patient had an attack of enteric fever in
October, 1919. No bacteriological tests were reported in the other errors. Of the three positive
tests reported in 1919, in 2 the disease was one of the paratyphoids, and of the 11 positive
tests of 1920, 7 were also paratyphoid (6 paratyphoid B).
Sex-Age Incidence.—The numbers of cases notified during the years 1914-18 are too few to
enable trustworthy sex-age-group averages to be calculated. The returns for the last two
years are compared below with the total numbers for 1914-18.

The differences in the incidence, both as regards sex and age, are rather striking. Still
more noteworthy is the fact that during 1919 no case was reported among males. Had the
decreased prevalence been limited to males at approximately "service ages," say 25-45 it might
have been permissible to suggest that the protective inoculation practised during the war was
the efficient cause. The reduction, is however, too general to justify such an assumption.
Institutional Treatment.—Whereas the proportion of notified cases removed to institutions
fell during 1914-18 to 76.6 per cent. as compared with 80.2 per cent. in 1909-1913, in 1919 the
proportion rose to 90 per cent. falling in 1920 to 84.2 per cent.
Fatality. Among the 29 notified cases—23 definitely diagnosed—there was only one death
prior to December 30, 1920, but one patient died at the beginning of the current year. The
fatality of the disease—based on verified cases and deaths during the year of occurrence—was
.zero both in 1919-1920, the first time that such a fact has been reported. During 1909-13 the
average tctal fatality was 16.1 per cent., and during 1914-18, 11.3.
Source of Infection.—In 2 instances in 1919 and 4 in 1920 the disease was believed to
have been contracted outside the Borough. Histories of consumption of oysters were obtained
in 2 instances, but enquiry failed to elicit any evidence ot contamination of the sources of
supply of the oysters. In one instance there was a history of consumption of mussels from a
source more than suspected to be polluted-
One patient was a member of a family in which several cases of enteric fever had occurred
over a period of years in various parts of the country.
Mention has already been made of the case erroneously diagnosed as enteric fever,
reliance being placed mainly on the Widal reaction. The patient had a definite attack of the
disease in the autumn of 1919 and was again notified early in 1920.