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Report of the County Medical Officer—General.
39
The first outbreak attributed to fried fish occurred in 1900, and a smaller prevalence was reported
in 1903. Study of the behaviour of the disease in the light of these occurrences then led to the conclusion,
that fish had probably been responsible for some, at any rate, of the excessive and widespread
incidence observed in London in 1898, 1899 and 1900. At this time, moreover, a large amount of attention
was being directed to the possibility of infection by shell fish, more particularly by oysters, and the
fall in prevalence of typhoid which followed in the early years of this century was very generally
attributed to the alterations which were effected, at about this time, in the conditions under which shell
fish were stored and manipulated. There can be no question as to the value of the improvements carried
out in this connection, which resulted from the reports of Newsholme and others as to individual cases
of disease attributed to oyster eating, and which were further stimulated by the reports on the occurrence
of two considerable outbreaks, which were traced by Bulstrode to oysters in 1903, and by the same
writer's detailed and exhaustive enquiries into the whole subject of the shell fish-industry. The attention
of the market authority, supplying London with fish and shell fish, was thus closely directed to the
possibility of risk from consumption of infected shell fish and fish, and the medical officer of health of the
City has referred, year by year, in his reports to this subject. In 1908 and again in 1910 and 1911
further fish outbreaks were reported, in East London, and it was now clear that these outbreaks were
especially associated with the consumption of immature plaice; increasing attention was given as the
result of these occurrences to the whole subject of fish inspection. It appears probable that the precautions
taken have had a share in producing the general decline in prevalence which is observable and
it is particularly worthy of note that while the excess of typhoid fever in London in the last quarters
of 1910 and 1911 was almost entirely due to infected fish, the years 1909, 1912 and 1913 exhibited
practically no corresponding autumnal increase at all.
The question which must now arise is whether the theory, broached by Koch in 1903, has stood
the test of experience, and whether the evidence of contact infection, adduced in Germany, can be held
to outweigh evidence incriminating water, milk, shell fish and fish which has by slow degrees been
accumulated in this country. It is possible, though the great authority of Murchison was against the
view, that direct case-to-ease infection plays some part in promoting spread of typhoid fever, but it
certainly cannot, on the evidence to hand, be held to merit anything like the importance attached to it
by the more extreme contagionists; indeed, if it did possess this importance, it would be necessary
to assume that the typhoid fever caused by water, milk, shell fish and fish was not the same disease as
that described by the Germans, for there has been a conspicuous absence of spread from case to case,
after considerable outbreaks of typhoid fever caused by water or food materials.
How, then, can the German results be explained? The ascription of so many cases to contact
infection may perhaps be understood from consideration of the following passage (p. 183) from the
German volume.
"If a case of typhoid fever cannot be ascribed to infection from another case in its neighbourhood,
and, if the search for a healthy bacillus carrier fails, inquiry must be made as to other possible
sources of infection (food, water, soil, etc.). In such case also, however, in the light of the experience
gained in South West Germany, a human being excreting bacilli is the cause of the mischief, and it is
only the intervention of an intermediary substance which removes the instance in question from the
category of ordinary contact infection. A sharp distinction cannot, of course, always be drawn between
'contact infection' and 'indirect transference,' for investigation is, as a rule, only made 14 days after
the commencement of the illness, and the probable date of the actual infection itself was presumably
14 days earlier still, making an interval of 4 weeks. Neither the patient nor his friends are able after
such an interval, not having made any precise observation at the time, to render assistance in discriminating
as to whether personal contact or transference (for example, by means of washing or foodstuffs)
has been in question. It is, therefore, possible that a number of those cases which are classed
as contact cases are really and truly instances of 'indirect infection.' "
This frank statement, taken together with that made, on page 441, to the effect that a far greater
danger to the town dweller than can be ascribed to contact infection is that of infection conveyed by food
materials, practically gives the case away so far as direct contact is concerned, and, if this be admitted,
the problem becomes one of determining the relative importance of the parts played, in "indirect infection,"
by manipulation of food, immediately prior to its consumption, on the one hand, and by exposure
of food to contamination in the gathering ground, foreshore, or estuary, on the other. The German
reports themselves, in the evidence they yield of grouping of cases, of failure of spread in the absence of
new importations, and of comparatively slight incidence upon those specially brought in contact with
the sick, all confirm similar evidence obtained in this country, which tells strongly against the view that
mischief is done at a comparatively late stage in the history of the distribution of the water or food.
It only remains to add that the campaign in South West Germany has not proceeded, no campaign
ever has, on the lines originally intended; on the contrary, first one and then another new position has
been taken up. Koch anticipated that clear evidence of spread from the sick would be forthcoming,
but his followers have tacitly admitted their failure to discover this class of evidence by their
appeal to the healthy carrier; Koch expected to find "house incidence" and "street incidence," but the
facts actually recorded, here, are difficult of explanation from the contact point of view; again, he
said it would be found that the child population constituted an ever-present menace, inasmuch as
they were harbourers of infection (he had already surmised that this might be the case in malaria), but
this suggestion, too, has been a particularly unfruitful one. Koch's followers have invoked the influence
of "regional immunity," brought about as the result of previous attacks, but all the facts which have been
forthcoming appear to discredit this hypothesis also. It has become necessary, in fact, to place entire
reliance upon the healthy carrier; and healthy carriers proving to be numerous far beyond anticipation,