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FOQDBORNE OUTBREAK OF SONNE DYSENTERY
An explosive outbreak of Sonne Dysentery involving 4 schools
simultaneously and leading to 313 proven cases occurred in June,
1954.
Investigations indicated that the outbreak was food-borne and
that the vector was almost certainly salad which had formed part of a
meal taken by the initially affected individuals on 16th June. The
degree of the problem may be indicated by the fact that on the 25th
June, 1954, of a total of 1,205 children on the combined rolls of
the A schools concerned, the head teachers reported 437 absentees,
of whom 340 were believed to be dysentery cases.
All general practitioners in the Borough were informed by
circular letter on the 22nd June, and their co-operation sought in
the exclusion of all cases and suspects from school pending satisfactory
"clearance" being assured, by means of a series of 3 negative
stool specimens.
Strict application of this exclusion measure by general practitioners
and school authorities naturally resulted in large numbers
of requests for such examinations Pressure on all staff concerned
and also on the West London Laboratory was consequently very great,
even though many practitioners did not refer patients for tests until
after clinical recovery.
Over a hundred specimens were submitted daily for at least two
weeks. Other measures taken included the closing of the Swimming
Baths to children from the affected schools and, at the suggestion of
the Medical Officer of Health, the London County Council temporarily
instituted chlorination of paddling pools in the area, and Day
Nurseries were screened for contacts.
Fortunately secondary cases did not reach uncontrollable numbers
as had been feared. Apart from kitchen and dining staffs at the
schools concerned, some 29 relatives who were either cases or strong
suspects, were found to be food handlers. Certificates under the
Public Health Regulations, 1953, were issued where appropriate.
By the end of July a large proportion of all cases were already
cleared. The numbers of outstanding cases diminished steadily
throughout August and by mid-October the situation was once more considered
normal.
The final figures for the outbreak may be given as follows:-