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of control advocated by the Infestation Control Division of the
Ministry of Agriculture, Fisheries and Food. The main poisons
used have been Warfarin and zinc phosphide and to a lesser degree
arsenious oxide. The vast majority of cases have been cleared by
one routine treatment and only a few instances of reinfestation
have been experienced.
Mice continue to be more numerous than rats and more
difficult to eradicate. Contributory factors in these difficulties
are the fears of occupiers that their children and/or their
domestic pets may pick up the poison baits, and also the absence
of occupiers at work or for some other reason. This is
particularly difficult when a house is in multiple occupation and
to be really effective it is necessary to treat all the lettings
within the house at the same time. In numerous cases, the
operators have arranged visits in the early morning or after
normal office hours to facilitate treatment.
In one case a valuable cat died at the same time that
treatment with poisonous baits was being carried out. Unfortunately
on the previous occasion some years ago, when rat treatment
was being carried out at this house the cat which the owner then
had died from oauses which were clearly not connected with the
rat poisoning. It appeared to the owner that it was stretching
coincidence too far for this to happen again and he was convinced
that the death of the cat was due to the poisons being used, A
post-mortem examination showed that the animal died from natural
causes.
Unlike the experience of many Metropolitan authorities,
very few rat infestations have been found to be due to defective
drainage. In 17 instances only has this been proved to be the
cause of infestations; exactly the same number as in 1957•
By virtue of the provisions of Section 11 of the
Prevention of Darrage by Pests Act, 1949. the Ministry have made
a 50 per cent, contribution towards expenditure incurred in the
eradication of rodents, but by the authority of Section 4, Local
Government Act, 1958, such grants will cease after 3lst March,
1959.
The following table indicates the number of premises
surveyed and/or treated during the years-
Business Premises Dwellings
Rats 12 495
Mice 18 745