Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
[Report of the Medical Officer of Health for Port of London]
definitely to exclude this diagnosis. The patient, after a severe illness lasting
over a month, made a complete recovery, and was discharged from hospital on
1st January, 1930.
The clinical history of this case was reported in the "British Medical Journal"
of 18th January, 1930.
V.—MEASURES AGAINST RODENTS.
(1) Steps taken for the detection of rodent Plague :—
During the year six rat-searchers were appointed.
Each rat-searcher has his own district, corresponding to the district of a Sanitary
Inspector, under whose guidance he works. A rat-searcher's first duty is the
examination of such ships in his district as are due for inspection under Article 28 of
the International Sanitary Convention relative to the granting of Deratisation and
Deratisation Exemption Certificates. His second duty is to visit ships arriving in his
district from Plague-infected ports, to search for dead rats and, if possible, to obtain
specimens of live rats trapped on board. He is required to re-visit, such vessels daily
during the discharge of cargo, to ascertain whether dead rats have been found in the
holds. The existence of rodent Plague on board any vessel in the Port should thus
be detected at the earliest possible moment.
The rat-searcher's third duty is the examination of shore premises for signs of
rat infestation or rat Plague, paying particular attention to premises adjoining the
berths of vessels from Plague-infected ports. For this purpose he maps out his district
into sections, each of which will take him about a week to examine thoroughly. He
then advises the warehouse keepers that a certain section will be under inspection for
a week, and requests him to carry out intensive trapping during that week and to keep
all rats caught until collected each day by the rat-searcher. In this way the whole
of the Docks will be systematically and regularly inspected for signs of rat-infestation
or of rodent Plague, and specimens of the shore rat population in all parts of the Port
will be regularly examined bacteriologically, so that, in the rare event of Plague
infection being communicated to the rats on shore, it should be quickly detected and
stamped out before it has spread extensively. Moreover, when rat-infestation of
premises is reported, the responsible persons are required to take energetic measures
of rat-destruction, for rat Plague will spread rapidly in a rat-infested area, whereas
where rats are few it may never spread at all. It is of the greatest importance, not
only from the public health, but also from the commercial point of view, that the
Port of London should be kept free from rat Plague.
Bacteriological Examination of Rats.—Owing to the fact that the Port of London
is so extensive, it is not easy to arrange for rats to be conveyed to a suitable
bacteriological laboratory. The new laboratories at the Seamen's Hospital, Greenwich,
are most conveniently situated, and there is a Staff of skilled bacteriologists under the
direction of Professor Hewlett. Rat-searchers collect rats from ships and shore
premises in their district each day. They tie to one leg of each rat a small label, on
which is a letter combination indicating the Dock where the rat was obtained (thus
R.A.D. indicates Royal Albert Dock, S.C.D. Surrey Commercial Dock, &c.) and a
number. In their daily report sheets the rat-searchers enter each letter-number
combination, with notes opposite showing exactly where and how each rat was obtained.
They then place the rats in a linen bag, which they put in a tin box. At the end of
the day they deliver the tin boxes at the laboratory of the Seamen's Hospital.
Greenwich, and receive in exchange empty bags and boxes for the next day's rats.
Rats are delivered about 5 p.m., and examined next morning. If any rats were found
Plague-infected the letters and number on the label attached would be telephoned to
your Medical Officer, who, on reference to the rat-searcher's reports, could at once
ascertain exactly where such rats were obtained and institute Plague preventive
measures there. If rats are found dead under circumstances suggesting that they
have died of Plague, they are taken at once to the laboratory, and an immediate
examination and report is requested.