SECTION XI - Measures taken against ships infected or suspected of Plague
The Fourth Schedule to the Public Health (Ships) Regulations, 1952, under the heading
"Additional measures in respect to the quarantinable diseases" — Part I — Plague, reads as
"(1) The Medical Officer may —
(a) require any suspect on board to be disinsected and place him under surveillance, the
period of surveillance being reckoned from the date of arrival of the ship}
(b) require the disinsecting and, if necessary, disinfection of the baggage of any infected
person or suspect, and of any other article on board and any part of the ship which the
medical officer considers to be contaminated.
(2) If there is rodent plague on board, the medical officer shall require the ship to be deratted
in a manner to be determined by him, but without prejudice to the generality of this requirement
the following special provisions shall apply to any such 'teratting —
(a) the deratting shall be carried out as soon as the holds have been emptied;
(b) one or more preliminary derattings of the ship with the cargo in situ, or during its unloading,
may be carried out to prevent the escape of infected rodents;
(c) if the complete destruction of rodents cannot be secured because only part of the cargo
is due to be unloaded, a ship shall not be prevented from unloading that part, but the
medical officer may apply any measure which he considers necessary to prevent the
escape of infected rodents."
Plague being primarily a disease of rats all vessels are inspected immediately on arrival at
their berths in the docks and river for the presence of any mortality among the rats on board which
is not attributable to any known cause, such as trapping, poisoning, etc.
Incidentally one of the "Health Questions" on page 1 of the "Maritime Declaration of Health"
requires the Master to answer "Yes or No" to the question "Has plague occurred or been suspected
amongst the rats or mice on board during the voyage, or has there been an abnormal
mortality among them?"
Any dead rats are immediately sent to the Central Public Health Laboratory at Colindale for
examination for bacillus pestis, each rat being accompanied by a label on which is given precise
information as to where the rat was found in order to arrive at a focus of infection should the
examination prove positive. The information is, of course, far more vital when the rat has been
found ashore than when found on board a ship.
In the event of a positive result the "additional measures" referred to above would be put
into operation — the discharge of the cargo would be promptly stopped and arrangements made for
the vessel to be fumigated throughout with hydrogen cyanide, with the cargo in situ, the vessel
being moved to an approved mooring.
Following the initial fumigation and collection of dead rats resulting therefrom, further
samples of such rats would be submitted for examination and the discharge of cargo would be
permitted under observation. The destination of the cargo would be forwarded to the Medical
Officer of Health of the district to which it was proceeding, together with an explanatory note.
If any of the cargo had already been discharged overside into lighters before the discovery of
plague infection, the lighters would be fumigated immediately.
On completion of the discharge of cargo from the vessel a second fumigation would be
carried out, again using hydrogen cyanide, to destroy the residual rat population, if any.
SECTION XII—Measures against rodents in ships from foreign ports
(1) Procedure for inspection of ships for rats.
The Port Health Authority employs sixteen Rodent Operatives working in conjunction with and
under the supervision of the Port Health Inspectors.
The Rodent Operative's first duty is to visit all ships arriving in his district to search for
evidence of rodents, paying particular attention to vessels which have arrived from plague infected
ports and to visit such vessels during the discharge of cargo and to ascertain that reasonable
measures are adopted to prevent any rodents escaping ashore.