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"In New York ships are furnished with a schedule of rat-proofing work required. We have not reached
that stage yet. But, as many of you are aware, a Sub-Committee of the Joint Sanitary Committee of the
Chamber of Shipping of the United Kingdom and the Liverpool Steamship Owners' Association has been
appointed to study and report upon the rat-proofing of ships. I do not know what stage their deliberations
have reached, but I have reason to believe that they are fully alive to the importance of rat-proofing, and
I have no doubt that their report will not only be of the greatest value to the shipping industry, but of the
greatest assistance to us. When this report has been issued, and has been studied by Shipping Companies,
we may even be asked to prepare schedules of the work necessary to make individual ships rat-proof.
I submit, therefore, that this Association should devote close attention to this subject and that we should
take every opportunity to pool our knowledge, our experience and our ideas in regard to the rat-proofing
of ships."
(ii.) On Shore:—
The Port of London Authority fully appreciate the value of rat-proofing, and
have issued instructions that all new work is to be structurally rat-proof. Every
recommendation of the Port Sanitary Authority receives careful consideration and,
while reconstruction goes steadily on, everything possible is done to keep the rat
population down to a minimum in the older parts of the Docks.
Rat Flea Survey.
During the year Dr. Kean continued the Rat Flea Survey he commenced last
year, and reports as follows:—
During the year ended January, 1934, an extension of the investigation into the
parasitic fleas of rats trapped in the Port was conducted.
The investigation was governed, in detail, by such conditions as were observed
during the conduct of the Rat Flea Survey for the year 1932-33.
The area investigated was that of the six zones into which, for the purpose of
rat-control, the Port Sanitary area has been divided.
Observations on Rats.
As in the preceding year, the recording of the species of rat under the heading
"Black Rat" or "Brown Rat" has been adhered to, and no attempt has been made
at a fine differentiation.
The report deals with the results of the examination of a total of 366 rats. This
number is composed of 180 brown and 186 black rats. Of the total, 127 rats were
found to be free from parasitic fleas. Flea-free rats were encountered most frequently
during the winter months, their numbers becoming gradually less with the onset of
the warm weather. The accompanying Table shows the percentages of flea-free rats
met with during the respective months of the period under review:—
1933. 1934.
Feb. March. April. May. June. July. Aug. Sept. Oct. Nov. Dec. Jan.
37.5 46.6 36.3 44.6 35.2 14.2 15.7 34.6 25.6 39.9 40 57.5
Per cent.
The greatest number of rats (130) was obtained from Zone B. Zones C and E
supplied 99 and 84 respectively.
On 11th September, 1933, a black male rat was trapped in No. 8 Warehouse,
South West India Dock. On examination this rat was found to have been harbouring
a solitary Xenopsylla cheopis male flea. This flea was forthwith submitted to the
Department of Entomology of the London School of Hygiene and Tropical Medicine
for verification of the identification. The identification was confirmed.
On 26th September two brown rats and one black rat were captured in this
warehouse. One of the brown rats, a male, was found to be infested with 13 fleas,
which were identified as follows: X. cheopis 1 male: C. fasciatus 4 male: Leptopsylla
8 male.
The adjacent berth is principally used by ships from India and the Persian Gulf.
Special attention was devoted to this area, but no further specimens of X. cheopis