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(2) Arrangements for the bacteriological examination of rodents, with special reference to
rodent plague, including the number of rodents sent for examination during the year.
As described in Section YI above, all rats for examination for plague, either by post mortem
and subsequently, if necessary, by bacteriological examination, are promptly sent to the Central
I'ublic Health Laboratory at Colindale.
The bodies are placed in polythene bags which in turn are placed inside metal boxes, sealed
and labelled so that there is no risk of the escape of any rat fleas during their transit to the
Laboratory. The boxes are, of course, delivered by hand.
The rat population of the Port is now so small and is under such strict' control that it can be
said to be almost certain that the arrival of a plague infected rat would be highly unlikely to have
any serious significance. In other words, an epizootic could not be introduced into the Port for
the simple reason that there are insufficient rats to enable the spread of infection. Nevertheless,
forty-three rats were went to the Laboratory and were examined for plague with negative results.
(3) Arrangements in the district for deratting ships, the methods used, and if done by a coramerical
contractor, the name of the contractor.
(a) The burning of sulphur at the rate of 3-lbs. per 1,000 cubic feet of space for a period of not
less than six hours.
The destruction of rats, whether it be by the open pot method or by sulphur gas, is efficient
and the great advantage is that when applied in the holds of ships, the crew need not be put
ashore. Unfortunately a number of countries have, for some time past, refused to accept as valid,
International Certificates, where this method of rat destruction has been employed; consequently
it has fallen out of use.
(b) The generation of hydrocyanic acid gas by various methods. For the destruction of rats a
concentration of HCN at the rate of 2-ozs. per 1,000 cubic feet of space is required with a
minimum of two hours contact.
(c) "1080" and "Warfarin". The employment of "1080" has been used regularly throughout
the docks for some time with highly satisfactory results and more recently its use in ships has
been equally effective. A certain number of ships have been deratted by this method in preference
to the use of cyanide, resulting in a considerable saving in time and cost to the shipowner.
Satisfactory results have been obtained from the use of "Warfarin" but a suitable bait, particularly
in granaries, with which to mix the poison, which rats will take continuously in preference
to grain or other forms of cereal on which they are normally feeding, has yet to be found.
(d) Trapping. Trapping is seldom employed save for the destruction of isolated rats which
have escaped a major poisoning operation or which have not yet established themselves.
The following are the names of the firms approved for carrying out the deratting of ships:—
Messrs. Associated Fumigators Ltd. Messrs. Fumigation Services Ltd.
Messrs. London Fumigation Co, Ltd. Messrs. Ridpests Ltd.
Messrs. Scientex (Southern) Ltd. Messrs. Insecta Laboratories Ltd.
PREVENTION OF DAMAGE BY PESTS (APPLICATION TO SHIPPING) ORDER, 1951
Owing to the nature of coastwise shipping trade which includes scheduled movements, part
cargoes and relatively quick 'turn round', there are difficulties confronting Sanitary Inspectors
who are responsible for exercising the provision of this Order, particularly with regard to the
issue of Rodent Control Certificates, e.g., most of the coasting vessels tie up in the River anddo
not go into the docks.
To assess the degree of rodent infestation reasonably correctly, the spaces inspected should
be empty and must be, at least, almost so. Accordingly it is evident that, in order to regulate
this part of the Inspectors' duties, more than one visit is frequently necessary to be present at
the opportune time.
In spite of this handicap, 103 ships have been inspected and have been granted Exemption
Certificates. There has been no occasion to enforce rodent extermination methods.
In connection with the rodent control of harbour craft, lighters in particular, some substantial
progress has been made in the working relations between the Industry and the Authority's
Officers.
There are signs that a 'rodent control consciousness' has spread to all concerned with the
lighters and the increasing co-operation at the repair yards is reflected in the greater number of
lighters being voluntarily deratted and recorded for the information of the Authority.
While full scale extermination measures are carried out wherever rodents are discovered in
lighters, simple rat-proofing of the compartments is not overlooked and advice on this modification
is always available to the Owners. Such a correction denies rodents access to any obscure
spaces that could be used as living accommodation, without which they can neither breed nor
survive.
Lighters inspected 3,142
with no evidence of rodents 2,689
" negligible evidence of rodents 329
" treated for rodents 112
Dead rats recovered after treatments 820
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