View report page

VI. MEASURES AGAINST RODENTS.
la Steps taken for the detection of Rodent Plague .
2. Measures taken to prevent the passage of rats between ship and shore.
3. Methods of Deratisation.
4. Measures taken for the detection of rat prevalence in ships and on shore.
5 s Rat-proofing .
The action taken under the above headings "was fully described in my
Report for 1947 and remains the same.
RODENTISIDES
Experimental work with Sodium Fluoroacetate ('1080'), begun in 1949, to
which I made reference in my Report for that year, was continued and expanded
throughout the present year with remarkably successful results.
Preliminary experiments were also carried out with anti-coagulants which
it was thought should have good results in the destruction of rodents provided
they could be persuaded to take a bait impregnated with an anti-coagulant in
sufficient quantity and regularly over a sufficient period to produce a
lowering of the thrombin element in the blood sufficient to produce fatal
haemorrhage.
Dicoumarin, the anti-coagulant used in the prevention of thrombosis in
humans, was tried, but later samples of an American preparation "Warfarin" or
"Compound 42" ms also tried, as well as a British preparation now on the market,
kno-wn as "Sorexa". It must be confessed that the first experiments were
failures in that they did not produce bodies and it is only recently (in 1951)
that better results have been obtained -with the British product.
It is important to make a distinction bet-ween the action. and, consequently,
the use, of '1080' and that of an anti-coagulant. '1080' is a short term
rodenticide, i.e. to be laid overnight and the results to be expected the following
day or at the most, if the baits can remain down with safety, after two days,
whereas the use of an anti-coagulant is a long term method only producing results
after a week or even a fortnight, but having the advantage that not being
poisonous in single doses can be allowed to remain in situ for a period with miich
greater safety than .1080'. Consequently, an anti-coagulant has distinct
preventive values in that, even if there is no evidence of an infestation or if
the infestation has been eliminated by *1080', re-infestation can be anticipated
by putting down an anti-coagulant in the expectation that rodents will be destroyed
before they have time to establish themselves and to nest and breed. Incidentally)
Warfarin is now being widely used in the United States and has gained a high
reputation as a rodenticide.
•1080' can, of course, never be used freely and widely on account of its
(14)