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gastrointestinal upsets occur which do not receive medical treatment at all, so that we are far
from having a complete record of the incidence of food infections in any year. However, in so far
as such mild infections do not cause illness they are practically inevitable in our society and
are part of the process whereby the individual builds up a natural active immunity to infection.
This, in so far as it is for the well-being of the individual and the community, is all to the good
rather than the mere scientific bacteriological investigation of minor infections to no useful
purpose.
1. Sources of Infection
Next let us look at the risk of infection from typhoid fever with regard to the various sources
of infection. Over the ten years from 1954 to 1963, the notifications in England and Wales were
respectively, 122, 193, 136, 125, 150, 123, 90 (the lowest ever recorded, 1960), 97, 130 and 247.
The annual number of deaths never exceeded 7 with an average of about 3 deaths per annum.2.
2. Risk of contracting infection abroad
Over this ten-year period an increasing percentage of cases of typhoid were contracted
abroad, the source of infection not being in this country, Some of these occurred in seamen and
travellers, but the vast majority of cases were contracted by persons abroad on holidays in
countries like Spain, Italy, Teneriffe. Some occurred as sporadic isolated cases, but coach
parties were involved, 13 cases occurring in one instance and 11 in another. In fact the risk of
contracting this infection abroad is now ranging between 25 to 40 per cent of the total cases
notified each year. Accordingly the chief medical officer of the Ministry of Health is continuing
to reiterate in his annual reports the desirability of holidaymakers being protected by TAB
immunization if travelling outside this country. The risk of contracting typhoid in this country is
considerably less than in many other European countries as is shown by the large percentage of
notified cases contracted there having regard to the relatively smaller number of persons at risk.
3. Risk of Water-borne Infection
One finding of the W.H.O. Expert Committee is self-evident, viz. 'The evidence of the importance
of safe municipal water supplies in controlling and preventing water-borne outbreaks of
typhoid fever is highly persuasive."3. Constant vigilance is necessary as is illustrated by consideration
of the two large-scale outbreaks of 1936 and 1937 reported in the paper by Dr. E.T.
Conybeare this afternoon.
With regard to European contracted infection, that associated with the Zermatt water-borne
outbreak in 1963 is so recent as to be well remembered. It is interesting that the development of
typhoid fever in three persons who had recently returned from Switzerland to this country drew
attention to this outbreak in the first instance. The first two diagnosed cases had travelled by
air to Zurich and then by train, stopping at Brique for a night en route to Zermatt. The three
cases in another party also travelled by air to Geneva and thence to Zermatt directly by train.
In all some 68 bacteriologically confirmed cases contracted their disease from the infected
Zermatt water supply.
In this Zermatt outbreak, a so-called non-specific gastro-intestinal illness of short duration
was widespread for several weeks before the outbreak was detected. This might well have been
taken as an initial warning and the water supply subjected to thorough investigation as a consequence.
The fact that the diarrhoea lasted a mere two or three days—a frequent enough occurrence
especially amongst visitors to the continent—may well have masked the realization of the
true nature and source of the infection. The preliminary dose of infection may also have been
small with local residents receiving immunizing doses, whereas the diagnosis of cases returning
to England drew attention to what was really at fault in Zermatt. Thirty-one of the cases occurred
in a single party of 95, indicating the concentrated infection of the water supply of one hotel in
this outbreak.
The public water supply has been not the only risk of contraction of infection by water in
recent years. The only common factor found amongst eighteen children in Durham Rural District
who developed paratyphoid fever was the habit of bathing in the River Browney in 1955. Phage
Type 1 organisms were isolated from the river and the patients4,5. Similarly, two cases of typhoid
fever in a village in Devon occurring at widely separated periods of time in 1956 and a fatal case
in 1957, were children who went to the same school. They were fond of wading in a local stream
into which a storm water overflow emptied crude sewage. The cases were infected with Vi Phage
Type A Salm typhi, as was an old man who had had typhoid fever some fifty years previously.
No previous cases were known to have been caused by this carrier; nor in fact was his carrier
state suspected till he came to reside nearby, and infected the local stream. Another instance
where water is concerned as a vehicle of infection was in 1956 when a boy fell into a pond in
Kent which was thought to be the source of his infection with typhoid fever. After admission to
hospital, three nurses contracted the disease, an illustration of the ever recurring risk of contracting
the disease directly from a patient or carrier.
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