London's Pulse: Medical Officer of Health reports 1848-1972

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City of London 1967

[Report of the Medical Officer of Health for Port of London]

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which was imposed in June 1965, has continued in force. A substantial number of shi ps
have been deratted by "1080" in preference to the use of cyanide resulting in a considerable
saving of time and cost to the ship owner.
(d) Trapping. This method is seldom used except as an expedient to eliminate isolated rats
and/or to secure specimens for the laboratory.
(e) Methyl Bromide. This is a very effective and lethal fumigant which has been used over
a number of years in the Port as an insecticide, particularly in the dried fruit industry. It
has considerable penetration powers and is not difficult to disperse after an operation. It
is also possible to use this gas as a rodenticide and where there is an infestation of
rodents and insects the combined problem can be solved with one operation,
The following are the names of the firms approved for carrying out the deratting of ships:—
London Fumigation Co. Ltd.
Contra-Ffe 6t Service Ltd.
Rentokil Laboratories Ltd.
(iv) Progress in the Rat Proofing of Ships.
No Change.
RODENT CONTROL MEASURES CARRIED OUT ON LIGHTERS
The application of the principal measure of rodent control on lighters, i.e. inspection for
evidence, has been pursued throughout the year. Of the total number inspected, 56 lighters
required deratting and from these a total of 277 rats were recovered. These figures are an increase
on last year, but are mainly accounted for by the unusual incidents of a refuse lighter becoming
infested with brown rats. After fumigation with S02, a total of 86 brown rats were recovered,
which included many young in nests.
Rat proofing of lighters, first introduced in 1959, has continued to be standard practice in
the industry and plays a very important part in maintaining the current rodent population at a
minimal level.
The methods of deratting employed throughout the year were:—
1. Sulphur dioxide gas
2. Methyl Bromide vapour
3. Sodium mono-fluoroacetate baiting.
The method of treatment is determined by the circumstances and degree of infestation at the
time of inspection.
Throughout the year, 473 lighters were fumigated with Methyl Bromide for insect control of
the cargo, at a dosage rate between 20 and 30 ounces per 1,000 cubic feet, dependent on the
specie of insect pest, with a twenty four hour exposure time. This dosage and period is more
than sufficient to destroy any rats that may be present in the lighter at the time of fumigation.
During the year, fifteen of the rats recovered from treated lighters were sent to the Public
Health Laboratory, Colindale, for routine bacteriological examination. Pasteurella pestis was
not isolated from any specimen.
SUMMARY
Number of lighters inspected 3,153
Number of lighters without evidence 2,903
Number with negligible evidence 194
Number of lighters treated for rats 56
Number of dead rats recovered 277
Number of rats sent for bacteriological
examination. All results were negative
for P. pestis. 15
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