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66
Baiting of Sewers.—The Borough Engineer has kindly supplied
me with the undermentioned information of the treatments carried
out in the Council's sewers in connection with the scheme:—
In collaboration with the Ministry of Agriculture, Fisheries and
Food, an experiment was conducted during the year 1959. Approximately
1,160 sewer manholes were baited with solid blocks
suspended over the benchings. The blocks consisted of pinhead
oatmeal, sugar, technical white oil and Warfarin No. 5. Rebaiting
was carried out at three-monthly intervals. It had been hoped that
this new technique would result in a major reduction in the rat
population of sewers, but this expectation was not realised. An
experiment limited to 12 months could not be regarded as conclusive,
but before proceeding further with this technique a new
experiment was carried out.
Two areas of the Borough were treated by Ministry personnel
using a bait of fluoracetate and fluoracetamide mixed with pinhead
oatmeal and water. The results were startingly successful in
reducing the rat population in these localised areas.
Following these most encouraging results the Council adopted
the use of sodium fluoracetate in ready mixed form for baiting sewer
manholes. In view of the toxic nature of this material, precautionary
measures were taken for the protection of the staff handling the
materials and a fresh survey of manholes was taken to select those
suitable for the introduction of this bait.
In October 1960, the bait was introduced into some 1,270 manholes
throughout the Borough. The Rodent Operatives of the
Public Health Department handled the material assisted by workmen
from the Borough Engineer's Department and baiting has
continued at four-monthly intervals. Following three successive
treatments a census baiting will be undertaken at a random selection
of 250 manholes throughout the Borough, in order to make a new
assessment of the effectiveness of this method of treatment.
Anti-Fly and Anti-Mosquito Campaign.—During the summer
period, April to September, the campaign has continued on
similar lines to previous years. Three men are employed in this
important preventive aspect of the Department's work consisting
of dealing with complaints and carrying out routine inspection and
treatment of sites where breeding may occur. A motor cycle with
a box sidecar is used to convey personnel and the necessary
appliances and materials.
The major factors to be controlled include house refuse
contained in the dust chutes and dustbins, food shops, cafes and
canteens, static water sites, ponds and ditches, etc.