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38
February. These rises stand in close relationship with the dates of full moons and the crowding
associated with the corresponding air raids. Notifications relating to measles, scarlet fever and
diphtheria have been examined, and the results are set out in detail in the accompanying diagram and
also in the following Table. In the former the operating series of raids and the corresponding rises in
the disease curves are indicated by the letters A, B, C. The earliest raids were not accompanied by
any considerable use of shelters. In the later raids the crowding was less marked. The dates given
in the Table are those of the full moons at the end of each month, those of the principal air raids,
and those ending the weeks in which overcrowding in underground shelters especially occurred; the
weeks in which evidence of flea prevalence was observed are noted and the behaviour of the three
principal infectious diseases in the first, second and third weeks following the overcrowding is described.
Dates ending the Behaviour of the Behaviour of infectious diseases in successive
weeks during flea prevalence weeks following the two specified weeks.
Dates of which tho use of curve in the two
Full Moon. Air Raids. underground weeks of preced.
shclters was ing column. 1st week 2nd week. 3rd week,
specially marked
(1) (2) (3) (4) (5) (6) (7)
30th Sept. 24,25,28,29, 29 Sept. Marked rise in S.F. Slight J/. Rise. S.F. Marked
30 Sept. 6 Oct. both weeks. rise rise.
1 Oct. D. Marked D. Slight
rise. rise.
30th Oct. 20 Oct. 27 Oct. Slight rise in D. Rise S.F. Marked M. Rise Main.
31st Oct. and 3 Nov. former and M. Commenc. rise tained.
1 Nov. possibly in ing rise M. Rise main.
latter weeks* tained.
28 Nov. 3, 6, Dec. 1 and 8 Dec. Marked rise in M. Rise.
both weeks.
28th Dec. 18 Dec. 22 and 29 Dec. Xo data avail. M. Rise M. Rise con.
(weather was able S.F. Slight tinues.
rough in latter rise. S.F. Rise
week and shel. D. Slight rise maintained
ters were not
much used)
27th Jan. 28 and 29 Jan. 2 and 9 Feb. Marked rise in M. Rise M. Rise niain.
both weeks. tained.
S.F. Rise.
25th Feb. 10, 17, 18 Feb. 23 Feb. and Rise in latter M. Rise. S.F. Rise M. Rise.
7 Mar. 2 Mar. week. S.F. Rise maintained
/ > Rise
* Schools closed during half.term holiday.
S.F.—Scarlet Fever.
D.—Diphtheria.
M.—Measles.
It will be seen from the Table that in each instance in which the data were available (col. 4) there
was an immediate rise in the flea curve corresponding with the period in which the use of underground
shelters was especially marked. In the next following week (col. 5) there was, generally speaking, a
slight rise in cither scarlet fever or diphtheria, and twice a commencing rise of measles. In the next
week (col. 6) there was always a rise of measles and twice a rise in scarlet fever. In the next week
(col. 7) there was, following upon the first set of raids in the Table, a rise in scarlet fever and in diphtheria.
It will be observed that the measles rises (col. 6) followed the special crowding after an interval
which would have allowed time for incubation and notification. In the case of scarlet fever, and still
more in that of diphtheria, the behaviour was less regular, and a rise sometimes appeared earlier and
sometimes later than in the case of measles. If these rises in prevalence are in any way associated
with the special crowding it is clear, in view of the fourteen days incubation period of measles and the
distinctly shorter incubation period of scarlet fever and diphtheria, that the measles rise must be looked
upon as a direct and immediate effect of the crowding, and the scarlet fever rise as being brought about
in some instances more indirectly. It may perhaps have occasionally resulted from a cumulative
influence, only becoming manifest after a lapse of time sufficient to enable the infection to be mediately
transmitted, and it is, of course, possible that increased diffusion of the disease, brought about by
a preliminary spread of fleas among children congregated together at the time of special crowding
may have played a part here. An analogy for such indirect influence is afforded by the relationship
noted as having been generally observed, during the last nine years in London, between development
in point of time of maximum prevalence of fleas and maximum prevalence of scarlet fever.
The total number of cases of measles and German measles reported as occurring among school
children during 1917 was 27,828, as compared with 76,121 among persons of all ages notified in accordance
with the Public Health (Measles and German Measles) Regulation, 1915. The prevalence of the
disease was most marked during the late winter months and in the spring. During the month of May
and throughout the summer there was a sharp decline, and during the succeeding autumn and winter
measles was practically quiescent. During the year one infants'department and 35 classrooms were
Measles and
German
measles.