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30
whooping cough.
WHOOPING COUGH.
Last year no fewer than 632 cases of this disease came to the knowledge of the Department,
that figure being higher than any recorded since 1904, when the present system of recording
attacks was initiated. From the figures given below it will be seen that the disease appears to
have been unduly prevalent during the past three years, the alternations of high and low
prevalence observed during 1904-09 not being continued after that last year. It is impossible at
this juncture to suggest any reason for the change.
Totals.
Quarters. 1. 2. 3. 4. Uncorrected. Corrected.
1906 57 65 26 26 174 171
1907 189 305 73 48 615 589
1908 34 65 37 35 171 170
1909 234 243 72 26 584 561
1910 137 182 95 134 548 518
1911 403 219 49 15 686 632
The 632 cases were reported from 344 houses, giving an average of l-8 cases per house, a
figure in excess of any average recorded since 1908 (average 1908, l.6; 1909 and 1910, l.7).
The secondary attacks numbered 288, and formed 45.5 per cent, of the total cases known, as
compared with 42.0 in 1910 and 1909, and 40.5 in 1908. The house distribution of multiple
cases is given below.
1906. 1907. 1908. 1909. 1910. 1911.
Houses with 2 cases 31 99 22 98 95 102
3 „ 17 49 16 41 38 51
4 „ 4 12 5 12 11 15
„ 5 „ 1 4 - 2 1 7
„ 6 „ — 1 - 1 2 1
„ 7 „ - — — — - 1
„ 8 „ — — — 1 — —
There were 45 deaths from the disease, so that the total fatality was 71 per cent., 0.4 above
the proportion observed in 1910, but equal to the average. From the statement given below it
will be seen that the fatality among males last year (7.2) was less than that recorded in 1910
(9.4), and also than the average (6.0); while the fatality among females (7.0) was higher than in
1910 (4.6), and also than the average (6.0). It may be noted that the number of cases reported
during the six months October-March, 1909-10, was 163, and that recorded during the
corresponding six months of 1910-11, 537. Such seasonal variation explains in part the
difference in the total fatality of the disease as recorded in 1910 and 1911, but it does not
explain why there should have been such a cross-over in the sex mortalities:—
Average,
.1906. 1907. 1908. 1909. 1910. 1906-10. 1911.
Males 8.3 9.2 8.8 6.4 9.4 8.4 7.2
Females 6.9 7.8 4.3 6.3 4.6 6.0 7.0
Persons 7.6 8.4 6.5 6.4 6.7 7.1 7.1
In Table 21 will be found the fatalities observed in the Wards last year in comparison with
the averages for the five years 1906-10. Unfortunately, it is believed that the information of the
attacks is even more incomplete than in the case of measles. In Table 22 the sex-age fatalities
of last year are compared with those for the preceding decennium. It will be seen that the
rates at ages under one year (males, 322; females, 26.1) were considerably higher than the
averages (males, 29.2; females, 25.6), while at ages 1.2 and 2.3 years the facts were reversed.
At ages above 3 years the rates are too erratic to be relied on.