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(i) Procedure for inspection of ships for rats.
The Port Health Authority employs an experienced and competent team of seventeen Rodent
Inspectors, who exercise control measures on all ships and shore premises within the Port area
under the supervision of the Port Health Inspectors.
The Rodent Inspector's first duty is to visit all ships arriving in his district as soon as
possible after arrival and search for evidence of rodents. Priority is given to ships which have
arrived from plague endemic areas. Further visits to these ships are made during the discharge
of cargo to ascertain the degree of infestation on board, if any, and to ensure that reasonable
measures are adopted to reduce the number of rodents on board to a negligible number and prevent
any rodents escaping ashore.
His second duty is the inspection of ships in his area for the specific purpose of issuing
Deratting or Deratting Exemption Certificates or Rodent Control Certificates.
The Rodent Inspector's third duty is the inspection of shore premises and lighters for signs
of rodent infestation.
The Port Health Authority has continued to operate a Rodent Control Scheme, inaugurated
twenty five years ago, covering all the docks and including all the premises of the Port of London
Authority on behalf of that Authority and premises of tenants of the Authority on behalf of the
occupiers.
(ii) Arrangements for the bacteriological examination of rodents, with special reference to rodent
plague, including the number of rodents sent for examination during the year.
All dead rats to be examined for evidence of plague, are promptly despatched in suitable
sealed containers to the Central Public Health Laboratory at Colindale.
The robust rectangular metal boxes which have been used for a number of years to deliver
such specimens have been replaced by a cylindrical pattern made of aluminium, with a scew cap.
Specimen rats are placed in polythene bags already dusted with gammaxene to kill any parasites,
labelled and placed inside the cylinder for delivery by hand. During the year 86 rats were
sent to the laboratory at Colindale and were examined for plague with negative results.
(iii) Arrangements in the district for deratting ships, the methods used, and if done by a commercial
contractor, the name of the contractor.
(a) The burning of sulphur at the rate of 31bs. per 1,000 cubic feet of space for a minimum
period of 6 hours. This method is seldom used now in the Port of London.
(b) The generation of hydrocyanic acid gas by various methods. For the destruction of rats
a minimum concentration of H.C.N. at the rate of 2 ozs. per 1,000 cubic feet of space is
required with a minimum of two hours exposure.
(c) Sodium-fluoraocetate ("1080") and "Warfarin". The employment of "1080" as a rodenticide
has been regularly used throughout the docks for some time with highly satisfactory
results. The prohibition on the use of "1080" and "1081" except in ships and sewers,
which was imposed in June 1965, has continued in force. A substantial number of ships
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-Pest Service Ltd.
Rentokil Laboratories Ltd.
(iv) Progress in the Rat Proofing of Ships.
The necessity for rat proofing has been recognised in modern ship construction. In post-war
years the principle was stressed as a measure to deny rodents conditions in which they could
hide in obscure places, have free communication between compartments and access to food or
drink. Previously many ships offered an open invitation to rodents and provided means for perpetual
infestation.
It has become the practice ef ship designers wherever possible to eliminate inaccessible
spaces where rodents can hide and nest and where such spaces cannot be avoided to ensure that
they are enclosed by materials through which a rodent cannot gnaw.
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