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33
Shellfish
outbreaks in
America and
in this
country in
1924.
The question of the association of typhoid fever with consumption of oysters
was, in 1924, raised once more in a striking way in this country and in the United
States. The origin of 83 cases of illness among persons who attended a banquet
at Portsmouth last November was traced by Dr. Mearns Fraser to consumption
of oysters. Furthermore, in New York and Chicago considerable prevalences of
typhoid fever, occurring late in 1924 in both cities, were as the result of most careful
enquiry traced to oysters and possibly to oysters from one and the same source.
In New York from November, 1924, to February 15th, 1925, a total of 798 cases
had been reported, as compared with 235 during a corresponding period in the
previous winter; of the 798 cases, 427 were attributable to oysters or clams. In
Chicago, between 30th November, 1924, and 21st January, 1925, there were 129
verified cases of typhoid, as against the previous seven-year non-epidemic average
of 33 cases. Out of the 129 cases ninety-two gave a history of having eaten one
or more meals, in certain high class restaurants and hotels, within the probable
period of infection, and the question as to the origin of the oysters consumed by
the persons taking such meals was investigated with great thoroughness. The
outbreak in Chicago started nearly a fortnight later, but began to decline about
the same lime as that in New York. At the time of writing (28th February, 1925)
all that could be said was:— "There is a possibility that the oysters responsible
for the New York outbreak are in part at least of the same kind as those believed
to be the cause of the infection in Chicago."
The Journal of the American Medical Association (24th January, 1925) in
commenting upon the outbreaks says:— "There is almost certainly much less
typhoid from oysters than there was 15 years ago; but when it does occur we are
able to detect it more readily." The point of view presented thus appears to be,
that as water-borne and milk-borne outbreaks of typhoid fever have become less
common, cases due to other and less important causes, e.g., cases of carrier infection
and of shellfish infection, are more often recognised. "We are simply," says the
writer, "able to pursue our enquiries at a different level, so that sources of infection
formerly submerged in a great wave of water-borne and milk-borne disease, can
now be seen rising as hidden reefs above the surface." The writer adds that, "For
some years health officers in Great Britain—where elimination of drinking water
infection antedated by some years that in the United States—have been led to
attach great importance to shellfish infection as a factor in their own present day
typhoid. In London, in 1923, out of 173 typhoid cases in which information was
obtained as to possible origin, fish or shellfish were held to have been at fault in 59
instances, or more than a third of the total."
Experience in London, however, suggests an alternative way of regarding
this problem, considered from the historical point of view. Here, in London, milk
infection and carrier infection have only in rare instances seriously come into
question at all; water, moreover, has not been clearly proved to be at fault, at any
rate during the last thirty years. Early in the nineties, shellfish, and in 1900, fish,
first came under suspicion; and the resulting enquiries of Bulstrode and others
concentrated attention on the special risk of infection from consuming shellfish
and small flatfish from polluted sources, estuarial or other. Study of London typhoid,
on the whole, therefore, suggests modification of the metaphor of a subsiding flood
and emerging reefs. It seems more natural, proceeding from the known to the
unknown, to think of the lesser hills now clearly discernible in the foreground of
the retrospect, as presumably stretching away toward more distant elevations and
possibly continuous with a mountain range of some altitude. There is, then,
complete agreement with the American writer as to the importance of shellfish in
connection with prevalences of recent years ; but considerable question arises when
he suggests that the heavy death rates of 30, 40, 50, or more years ago—reaching
back to the time of commencement of death registration—were due mainly to
quite other causes. From the London standpoint the subsiding flood and emerging