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Toxicity.
When tested pharmacologically on rats and mice it has an L.D.—50 about seven times that
of "1080", i.e. about 14 mgm. per kgm. body weight for the amide and 1-2 mgm. per kgm. body
weight for the sodium salt. This indicates that "1081" is very much less toxic to rats than
"1080".
Despite its relatively low toxicity, it is almost certain to warrant a prominent place among
present day rodenticides.
It has been established in research work that the toxicity of "1080" is due to formation of
fluorocitrate in the live rodent and it is suggested that "1081" is converted more slowly into
this toxin as compared with "1080", thus giving smaller blood concentrations of fluorocitrate,
which is sufficient to kill the rodents without the epileptiform convulsions so characteristic of
"1080" poisoning.
Since "1081" is less toxic than "1080", there is a wider margin of safety in using it in
rodent control.
Antidote.
As yet there is no known antidote for either "1080" or "1081", but it has been observed
that rats pre-dosed with Fluoroacetamide 12-24 hours before, usually survive the administration
of "1080", which may be a pointer in the search for an antidote for this poison.
Trials.
Fourteen operations have been carried out on premises where stacked, rodent attractive foodstuffs
predominated and provided harbourage.
The selected sites were affected by slight, but very persistent infestations of rats and/or
mice due, in some cases, to rodents in parcels of incoming cargo and, in others, to bulky stowage
over considerable periods of time-
In some respects it has been unfortunate that there was no site of infestation in the docks
where a spectacular result could be obtained, but one operation outside the docks has proved
quite conclusive. Here a large colony of rats, hitherto persistent, has been eliminated in a single
operation over a week-end.
Either poisoned water or soaked cereal baits were used with a concentration of 0.5%. Baits
were contained in plastic trays and strategically deployed exactly as for "1080" operations.
In almost every operation visible results were forthcoming within the first 24 hours check
and poisoned rodents collected.
The amount of poisoned baits taken indicated that either it was lacking in effective toxicity
or that dying rodents had escaped into the harbourages. Owing to the lower toxicity of "1081", it
was anticipated that poisoned rodents would survive long enough to retreat into harbourages and
die there, thus rendering any immediate results inconclusive.
This, in fact, has happened and it is only when the stacks of cargo are being broken down
and delivered that more dead rodents are recovered.
Conclusions.
These earliest field trials have proved very encouraging and indicate the usefulness of
Fluoroacetamide—"1081"—as a rodenticide, especially where the more toxic "1080" cannot be
used with a reasonable margin of safety to human beings and domestic animals.
There is every indication that it can be used in a variety of ways as a readily acceptable
rodenticide and, providing the applied technique is carefully planned, satisfactory results should
be achieved overnight. The minimum effective concentration for rodent control appears to be
0.5%.
It is noteworthy that some rodents were recovered near to the poison bait and in a
comfortable resting posture, without any signs of pain or rigors.
PREVENTION OF DAMAGE BY PESTS (APPLICATION TO SHIPPING) ORDER, 1951.
The provisions contained in the above-named Order have been exercised fully during the
year under review and Rodent Control Certificates in the form prescribed in the Order have been
issued to 61 coasting vessels, none of which required deratting treatment.
The number of Rodent Control Certificates (61) issued is significantly less than last
year (101). This reduction has been influenced by the issue of International Deratting Exemption
Certificates to coastwise vessels that have been chartered to import coal from the Continent as a
diversion from their normal trade.
The inspection of harbour craft, especially lighters, has been intensified during the year
and appropriate measures taken to destroy rat infestations whenever such action has been
justified.
Although rat-proofing measures are not included in the provisions of the Order, the wisdom
of denying harbourages in which these pests can hide and breed, cannot be ignored and, to this
end, suggestions and advice has been sought by several owners and submitted by the Authority
when and where applicable. Such rat-proofing measures include simple and relatively inexpensive
modifications which are carried out at the repair yards.
The beneficial effect of rat-proofing is apparent by the considerably reduced ratio between
lighters inspected and those found to harbour rats—
Number of lighters inspected 3,267.
,, ,, ,, without evidence of rats 2,814.
,, ,, ,, with negligible evidence of rats 369.
,, ,, ,, reported for treatment 84.
,, ,, rats recovered after treatment 427.
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