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40
Primary Inoculations and 2,109 Reinforcing Inoculations.
(Figures for 1950 were 755 Primary Inoculations and 513 Reinforcing
Inoculations.)
Paratyphoid " B."
Two cases of paratyphoid "B" were notified, one on the 13th
July, 1951, and the second on the 17th July, 1951—the date of
onset of symptoms in each case being respectively the 7th and
12th July.
The delay in notifications was mainly due to the difficulty
of diagnosis and to the time taken for bacteriological and
serological verification. It is this delay between onset of illness
and the confirmation of the diagnosis that makes any investigation
into the source of this disease so difficult. In cases of
paratyphoid infection, there is also to be considered the period of
incubation which, in some cases, may be as much as two weeks.
As a general rule, one can accept that paratyphoid "B" is a food
infection and not a "case to case" infection.
On investigation being made into these two cases, there
appeared to be no connection—the one at Sidcup had no relation
or contact with the case at St. Paul's Cray. It was only on the
occurrence in the same week of a case in the Orpington district
that a relationship was found between all three. All these
families had purchased cakes from the same baker, and possibly
had purchased "iced lollies" which, although obtained from
different itinerant dealers, were found to come from a common
source. The investigation made into the "iced lolly" source,
however, proved negative and we were left with the Baker as the
only possible source of infection. It was known that this Bakery
covered a very wide area in North West Kent and there was
definite evidence in two of the three cases that cream buns had
been eaten from this supply. On communicating with the
Medical Officer of Health of the area in which this firm is
established, it was found that another case had arisen about the
same time in his own area—the baker being the same itinerant
supplier. Steps were immediately taken by this Medical Officer
to investigate and control the source of supply. In the meantime
a further case arose in the Orpington district and other cases in
Lewisham, Dartford and Dartford Rural District and Crayford.
Of the fourteen cases which thus came to notice, eleven had the
same baker and there was evidence that cream buns had been
eaten. There was, therefore, presumptive evidence that the
infection lay with the " cream." As a result of action taken,
there were no further cases.
The comparatively small number of cases notified bears little
relationship to the number of persons who may have been
infected, for it is noteworthy that, in epidemics of Paratyphoid
"B," cases occur which are not severe enough to call in medical
aid and, therefore, escape supervision.