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Its use is somewhat complex in that some countries particularly the United States and
Canada require a certificate to be produced by the Master of a ship prior to the loading of
grain to state that the ship is free from insects or has been disinsected by an approved
fumigant. such as methyl bromide. This applied particularly in the case of Khapra beetle
infestations. No such certificates can be obtained in the United Kingdom and therefore in
order to satisfy the requirements of a particular port and to avoid possible delay in
loading. the vessel is fumigated with the appropriate amount of methyl bromide. This is
entered on the De-Ratting certificate which then serves the dual role of showing that the
vessel has been de-ratted and disinsected.
The exposure to the gas depends on the concentration and on the period and purpose
of the exposure. For example, 16 oz. of liquid per 1.000 cu.ft. for 24 hours for insect
infested bones has been used; for Khapra Beetle infestations the United States Authorities
stipulate 48 oz. per 1,000 cu.ft. for 24 hours or 96 oz. [Per 1 000 cu.ft. for 12 hours; in
United Kingdom ports, 32 oz. per 1.000 cu.ft. for 24 hours is usual. Such concentrations
are more than adequate for eradication of any rodent or insect life present in the vessel.
The following are the names of the firms approved for carrying out the deratting of ships:—
Etoxin Ltd..
Contra-Pest Service Ltd..
Rentokil Laboratories Ltd.
(iv) Progress in the Rat Proofing of Ships
No Change.
RODENT CONTROL MEASURES CARRIED OUT ON LIGHTERS
Rodent control measures on lighters have been carried out during the year. Of the 2,686
lighters inspected for rodent indications, 1,825 were inspected on the Upper and Middle River
District, the remaining 861 inspections being carried out in the respective dock groups. By
referring to the attached table. it will be observed that there has been a slight increase in the
number of lighters requiring treatment but the average number of rats recovered after treatment is
the lowest yet recorded. During the past ten years 42.021 inspections of lighters have been
carried out and only 1.7% of these required treatment.
The Importance of Rodent Control on Lighters
Dangers to health and to prevent the spread of disease
Rats and mice are suspected carriers of disease and their presence represents a potential
health hazard by virtue of the contamination of stored human food they eat and foul. Food poisoning
and other infections may be spread to man by his consumption of rat contaminated foodstuffs.
There is the danger of bubonic plague transmitted to man by fleas, particularly the rat flea,
Xenopsylla cheopis. This flea will accept man as an alternative host and transmit the disease
to him.
Rats also carry one form of Typhus, Endemic Typhus which is transmitted to man by fleas.
Weil's Disease (Leptospiral Jaundice) is transmitted to man by direct or indirect contact with
rats and their infected urine.
Economic Rurden
Damage to food supplies merchandise and structures
Rats and mice are prolific breeders. It is essential, therefore that the most efficient control
measures are used. The ultimate aim of any operation carried out is to exterminate every single
rat, not leaving any residue rats, as these will soon multiply and cause a reinfestation.
Rat Suppressive Measures
Fumigation and poisoning — no change
Cleanliness and hygiene — no change
Harbourage and rat-proofing — no change
The methods of de-ratting employed throughout the year were:—
F umigant s Rodenticides
1. Sulphur Dioxide Sodium mono-fluoroacetate
2. Methyl Bromide
The method of treatment is determined by the condition and degree of infestation of the
lighter at the time of inspection.
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