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Food Poisoning
An outbreak of food poisoning caused by the organism salmonella
typhimurium occurred at an Independent School in April.
The Health Department had not been notified about the outbreak,
but information from a Public Health Laboratory led to inquiries
which revealed that positive results had been obtained on
specimens from two pupils at the school. The school was then visited
and it was ascertained that 42 pupils out of a roll of 155, together with
one teacher and the housekeeper had been ill the previous week and
absent from school. After full investigation 51 positive cases were
found.
It was discovered that some of the school meals were cooked
at the caterer's home and transported to the school. The caterer and
one of her two children were found to be positive. Swabs were taken
from the working surfaces and equipment at the school kitchen and
the caterer's home, but all these results were negative. The contaminated
food causing the outbreak could not be identified owing to the
length of time which elapsed before the Health Department found out
about the outbreak.
A number of boys who had been ill were allowed back to school
while still positive, one week after symptoms had ceased, with special
arrangements as to toilet and hand washing facilities. In six cases
the infection was found to have spread to other members of the boys'
families.
Since the outbreak a wash-hand basin has been installed in the
kitchen toilet and hand washing notices are displayed in the kitchen.
The caterer was advised not to use her home for food preparation.
The last case was not cleared until late in July and more than
450 specimens were sent to the Public Health Laboratory for pathological
examination. Several other local authorities were involved,
since the school's pupils come from a very wide area.
In addition to this outbreak, there were 21 individual cases as
listed below, involving 82 persons: —
Salmonella bredeney 1
„ enteritis 4
„ Indiana 2
„ Heidelberg 1
„ Panama 4
„ typhimurium 5
„ Virchow 1
„ untyped 3
Forty suspected cases, involving 73 people were also investigated,
all proving negative.
Smallpox
Twenty-eight persons arriving in the Borough without a valid
International Certificate of Vaccination were kept under surveillance
for the necessary period.
Cholera
Four cholera contacts were also kept under surveillance for the
prescribed period.
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