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103
Report of the Medical Officer of Health.
It transpires, therefore, that shop 5 is named more than 6 times as often; shop 11, 6 times as
often; and shop 18, 6 times as often, as would have been anticipated were the distribution of names
a mere matter of chance.
Furthermore, it will be seen that 49 of the 50 sufferers had obtained fried fish from one or
other of these three shops. The fiftieth was the case diagnosed in error. It remains to be stated that
the fish sold at shops 11 and 18 was brought by a particular man from Billingsgate. This incidence
upon three shops, or as it may also be put upon two fish supplies, is very striking. It cannot be
urged in explanation that these shops happened to be centrally situated, and therefore were named
more frequently; for shops Nos. 1, 4, and 8 are, as a matter of fact, situated, if anything, more centrally
than are shops 5, 11 and 18. Shop 5 is close to shops 4 and 8; and yet while shops 4 and 8 were only
quite exceptionally mentioned, no fewer than 25 of the sufferers had purchased fish at shop 5. It
should be noted that shop 5 was, moreover, a shop which especially fell under suspicion in connection
with typhoid fever in 1908. (See Appendix I. to Annual Report of the Medical Officer of Health, County
of London, 1908.)
So far as the Bethnal Green special area was concerned, therefore, an hypothesis of infection
by two particular consignments of fish sold at three fried fish shops affords complete explanation of
the outbreak. Outside the special area, however, but within Bethnal Green, there were certain small
groups of typhoid fever cases. It is necessary now to discuss these and other groups in London and
the suburbs occurring at the time of the prevalence in the special area itself.
Examination of the Behaviour of Typhoid Fever in London Generally and in some Areas Outside the
County Boundary.
Question was, in fact, now seen to arise as to the possibility that fish, sold at various shops
throughout London during August and September, gave rise to typhoid fever. The cases in 10 London
boroughs, and in two districts just outside London showing special prevalence of typhoid fever during
these months, were found, as has already been stated, to fall into clusters or groups. These groups,
33 in number, consist in the main of cases in which none of the ordinarily accepted modes of origin
of typhoid fever could be appealed to for explanation, but in which the sufferers had either eaten fried
fish purchased at one particular shop in each group, or had eaten fish purchased in the uncooked condition
from one or another common source (shop, stall or market street). After separating out these
groups of fish cases there remain in each district residua of cases which cannot be associated with fish
obtained from any particular source. The cases forming these residua present, in a few instances, a
history suggesting infection abroad, or in some other part of England ; in other cases (the majority),
no obvious source of infection was ascertainable. The residual cases represent, area by area, approximately
the number of cases which might reasonably be expected to occur, apart from any special cause
in the 12 areas.
So far as the London boroughs are concerned, the date of onset of symptoms has been determined
in every case, and each has been given a distinctive serial number in the particular group in the
borough to which it belongs. This arrangement of the cases will be rendered clear on study of the
accompanying Diagram. The cases are distributed in horizontal zones or sections of the Diagram,
as follows; —
1. Bethnal Green—Cases include those supplied from shops A, B, C, and D.; from market
streets a and b; and a residuum of cases.
2. Shoreditch—Cases include those supplied from market streets b, c, and from a market
street d; those last-named being included with a residuum of cases.
3. Islington.—Cases include those supplied from shops E, F, G, H, I, K, and stall L, with
a residuum of cases.
4. Finsbury—Cases include those supplied from stall, L, shop M, and a residuum of cases.
5. Stoke Newington—Cases include those supplied from shop N, and a residuum of cases.
6. Hackney—Cases include those supplied from market streets b and e, shop P, and a
residuum of cases.
7. Poplar—Cases include those supplied from shops D and S, by a coster R, and a residuum
of cases.
8. Stepney—Cases include those supplied from shops S, T, and V, stall U, market streets
a and f, and a residuum of cases.
9. St. Pancras—Cases include those supplied from stalls W and X, from street g, and a
residuum of cases.
10. Holborn—Cases include those supplied from stall X, and a residuum of cases.
As regards distribution of the cases in time—the whole period covered dates from early August
to the middle of October. It will be seen, however, that while in 24 of the horizontal sections which
correspond to sources of fish supply, the dates of onset range (with one or two exceptions to be later
referred to) from early August to late September, in seven of the horizontal sections the dates
commence some three weeks later, and correspondingly terminate about three weeks later also.
The seven sections in question are : Islington (shop K), Hackney (sources e and P), Stepney (shop V),
St. Pancras (sources g, W and X)—X appearing also in Holborn.
The sections shaded include the residual cases, those apparently not due to fish infection. It
should be noted that towards the right hand side of some of the shaded sections (Bethnal Green,
Islington and Stepney), there is some grouping or aggregation of cases. The explanation of this aggregation
may possibly be that some unrecognised source of infection was playing a part in the boroughs
concerned at the time ; it has, however, been found impossible to indicate this particular source.