K. Serotherapeutischen Institut and by Doctor Reichel, assistant in
the Hygienic Institute of the University of Vienna, follow:
From the stools of one of the patients infected from milk an organism
was isolated which, injected into mice (1 c. c. emulsion of
forty-eight-hour culture), killed them in two to five hours. Mice
infected by eating these dead mice died in thirty to forty-eight
hours.
Control mice inoculated similarly with a culture of the market
mouse-typhoid virus died in twenty to thirty hours, while the mice
infected through eating these died after three to four days.
The following strains were used for cultural agglutination tests:
A. From stools of patient infected from milk.
B1. Market virus used in injecting mice.
B2. Market virus taken by author.
C25. From stools of author twenty-five hours after infection.
C55. From stools of author fifty-five hours after infection.
LL. Stock culture of Loeffler’s mouse-typhoid bacillus.
LP. Stock culture of para-typhoid bacillus.
All organisms (A-C55) were demonstrated as motile bacilli, not
liquefying gelatine, not forming lactic acid, and forming gas from
dextrose.
The serum of a rabbit after two injections of LL agglutinated LL and
LP in dilution of 1:1280, did not agglutinate A, B1, B2, C25, and C55.
Serum of rabbit after one injection of B2 agglutinated in 1:320
dilution A, B1, B2, C25, C55, and LL; did not agglutinate LP.
Serum of rabbit after one injection of C25 gave exactly similar
results.
Doctor Reichel considers it proven that the organisms A to C55 are
undoubtedly identical with Loeffler’s bacillus of mouse typhoid, and
distinct from para-typhoid bacilli. The author considers it proven
that this bacillus was the sole cause of the cases of enteritis
observed.
Recently Mallory and Ordway[BM], in a paper read before the American
Association of Pathologists and Bacteriologists held in Boston,
reported that lesions analogous to the early stages of typhoid lesions
may be produced in rats by the use of Danysz virus.
Footnote BM:
Mallory, F. B., & Ordway, T.: Lesions produced in the rat by a
typhoid-like organism (Danysz virus). Journ. Am. med. assn., vol.
52, May 1, 1909, p. 1455.
In view of these facts the statements of some of the advertising
matter of certain rat viruses call for revision.
REFERENCES TO THE LITERATURE.
Loeffler,[BN] 1889, gives an account of two spontaneous outbreaks
among the mice kept at the Hygienic Institute at Griefswald. It was
from these animals that he obtained and described the original _B.
typhi murium_. He determined that the infection was by ingestion and
that the organism was especially virulent for field mice. He described
the organism in detail and also the lesions.
Footnote BN:
Loeffler, F.: Ueber Epidemieen unter den im hygienischen Institute
zu Griefswald gehalten Mäusen und über die Bekämpfung der
Feldmäusplage. Centblt. f. Bakt., Orig., vol. 11, 1898, p. 129.
Laser,[BO] 1892, reports that on the morning of February 6, 1892, 70
of the 76 field mice (_Mus agrarius_) used as experiment animals in
the Hygienic Institut at Königsberg were found dead. A small bacillus
twice as long as broad, displaying a very lively specific motility,
was isolated from the spleen. It was tested upon animals and all the
results compared with Eisenberg’s tables and found to be closely
allied to the bacillus of ferret plague (Ebert-Schummelbusch), to the
bacillus of American swine plague (Billings), and to that of French
swine plague (Chantamesse and Cornil).
Footnote BO:
Laser, Hugo: Ein neuer für Versuchsthiere pathogener Bacillus aus
der Gruppe der Frettschen-Schweinseuche. Centblt. f. Bakt., Orig.,
vol. 11, 1892, p. 184.
Mereshkowsky,[BP] 1893, isolated an organism at the Royal
Bacteriological Institute at St. Petersburg from a stock of Zisel
(_Spermophilus musicus_) among which a spontaneous epizootic had
occurred. The author found this culture to be virulent for domestic
and field mice.
Footnote BP:
Mereshkowsky, S. S.: Ein aus Zieselmäusen ausgeschiedener und zur
Vertilgung von Feld-resp. Mäusen, geeigneter Bacillus. Centblt. f.
Bakt., Orig., vol. 17, 1895, p. 742.
Zupnik,[BQ] 1897, states that Joseph, of the Agricultural Institute of
Breslau, in 1882 originated the use of favus fungus for the
destruction of mice. Zupnik tested _B. typhi murium_ and Danysz virus
upon mice. No experiments with rats.
Footnote BQ:
Zupnik, Leo: Ueber die pratische Verwendbarkeit der Mäuse bacillen
inbesondere des Loeffler’schen _Bacillus typhi murium_. Centblt. f.
Bakt., Orig., vol. 21, 1897, p. 446.
Issatschenko,[BR] in 1898, described briefly a bacillus obtained by
him from gray rats. Recent investigation showed this bacillus to be
very virulent for rats and mice, but harmless for the different
species of domestic animals. Four hundred and forty-three experiments
were made upon rats with pure cultures of the bacillus combined with
dough and fed to the rats. He gives a table showing that the mortality
occurred in 431 rats at an average of ten and one-half days. The
greatest mortality occurred during the first fifteen days (84.2 per
cent), with the greatest number on the seventh day (20.1 per cent).
Footnote BR:
Issatschenko, B.: Untersuchungen mit dem für Ratten pathogenen
Bacillus. Centblt. f. Bakt., Orig., vol. 31, 1902, p. 26.
Danysz,[BS] 1900, isolated a cocco-bacillus during an outbreak of
spontaneous disease amongst field mice which presented the general
characteristics of the colon bacillus and to this extent resembled
Loeffler’s bacillus (_B. typhi murium_), and which from the beginning
exhibited some pathogenicity for gray rats (_M. decumanus_). Of ten
such rats fed upon a culture of this organism, two or three died,
while others that had fallen sick recovered and the same remained
well. This small mortality offered some hope that it would be possible
to increase the virulence of the bacillus by ordinary methods; that
is, passing it from rat to rat. It was found, however, that the
opposite was true; the virulence was always weakened by this process
regardless of the method of administration. Thus in every series the
first culture killed the animals in seven to twelve days; occasionally
after one or two passages five to seven days; but subsequent passages
decreased the virulence so that none died.
Footnote BS:
Danysz, J.: Un microbe pathogène pour les rats (_Mus decumanus_ et
_Mus rattus_) et son application à la destruction de ces animaux.
Ann. Inst. Pasteur, 1900, vol. 14, p. 193.
The general result is that it is difficult to maintain the virulence
of the cocco-bacillus of the rat or to increase it when it is found to
be small. It can only be effected by constantly making a large number
of experiments and frequently testing the virulence of the culture.
Danysz succeeded in keeping up a supply of cultures of sufficient
strength for eight years. In 60 per cent of the operations where this
culture has been used it has been successful in causing the absolute
disappearance of the rats. In 15 per cent the result was entirely
negative, and in the remaining 25 per cent there was a large
diminution.
Oettinger,[BT] in 1903, increased the virulence of the Danysz bacillus
by growth in an egg rendered alkaline after the method previously
introduced by Wiener.
Footnote BT:
Oettinger, M.: Ueber die Wienersche Methode zur Virulenzsteigerung
der Danysz Bazillen. Munch. med. Woch., vol. 1, 1903, p. 324.
Pfreimbtner,[BU] 1904, sees the reason for a partial failure in the
application of Loeffler’s bacillus to the destruction of field mice.
In the use of a solid medium (agar-agar), upon which the bacterial
cultures only grow upon the surface, too few bacteria are transferred
to the pieces of bread, and consequently too few virulent bacteria are
consumed by the mice. An active infection depends not upon the
existence of virulent bacteria, but rather upon the entrance of a
definite number of virulent bacilli.
Footnote BU:
Pfreimbtner, J.: Erfahrung über des Loeffler’schen
Infektionsverfahren zur Bekämpfung der Mäuseplage in einer neuen Art
der Anwendung. Fühlung’s landw. Zeit., 1904, p. 619. Rev. by
Schander in Centblt. f. Bakt., 2. Abt., vol. 15, 1905, p. 502.
The author used skimmed milk as a nutrient medium and describes a
series of 9 experiments and gives an estimate of the cost of the
process with the use of milk instead of agar. The advantage of the use
of milk is in the greater certainty of the results and cheapness as
compared with other methods. The bread cubes impregnated with skimmed
milk were well taken by the mice and desiccation of the cultures,
which not infrequently occurs in the use of more solid media, is
excluded. Notwithstanding the excessive thinning, the liquid still
contains many virulent bacilli. The washing out of bacilli after rain
is slightly less possible as in the use of the more solid media. The
action of light, where the bread cubes contain many bacilli, is
insignificant, and hence the carrying out of the process in the
daytime is made possible. Milk is easily obtained and the thinning and
application less bothersome. Finally the author expresses himself
against the view that the _B. typhi murium_ causes serious diseases in
man.
Teichert,[BV] 1905, speaks of Loeffler’s mice typhus bacillus and
Pfreimbtner’s method of growing it upon sterilized skimmed milk. A
number of experiments carried out at the bacteriological laboratory of
the Vreschen experiment station shows the utility of Loeffler’s
bacillus for the destruction of house and field mice. The long-tailed
field mouse was, on the other hand, not harmed by it.
Footnote BV:
Teichert: Die mechanischen, chemischen und bacteriellen Kampfmittel
gegen Ratten und Mäuse. 2. Teil: Die Bekämpfung der Mäuse. Fühlung’s
landw. Zeit., 1905, No. 16. Rev. by Ehrenberg in Centblt. f. Bakt.,
2. Abt., vol. 15, 1905, p. 503.
Bahr,[BW] 1905, gives a complete and satisfactory summary of the
literature upon the subject of the destruction of rats and mice with
bacteria, including original work of his own.
Footnote BW:
Bahr, L.: Ueber die zur Vertilgung von Ratten und Mäusen benutzten
Bakterien. Centblt. f. Bakt., Orig., vol. 39, 1905, p. 263.
Zielander,[BX] 1908, obtained fairly good results with Danysz virus in
the laboratory, also with ratin. No fixed tests were recorded.
Footnote BX:
Zielander: Der Rattenbacillus als Rattenvertilgungsmittel. Arb. a.
d. k. Gesndhtsmte., Berl., vol. 28, 1908, p. 145.
RÉSUMÉ.
Rats are notoriously resistant to bacterial infection. Even plague
usually fails markedly to diminish their prevalence. An epizootic of
bacterial nature, therefore, can not be classed with the natural
enemies of the rat. We are not surprised, then, to learn that the
bacterial viruses have signally failed to accomplish their mission.
These bacterial viruses belong to the colon-typhoid group of
organisms. They are either identical with or closely related to the
original bacillus of mouse typhoid discovered by Loeffler, or the
para-typhoid bacillus type B, which is frequently the cause of meat
poisoning, or the _Bacillus enteritidis_ of Gærtner, which has been
associated with gastro-intestinal disorders.
The claim that these rat viruses are harmless to man needs revision,
in view of the instances of sickness and death reported by various
observers. The pathogenicity for man depends upon the virulence of the
culture, the amount ingested, the nature of the medium in which it
grows, and many other factors.
Danysz virus is pathogenic for rats under laboratory conditions, but
has feeble powers of propagating itself from rat to rat. It rapidly
loses its virulence, especially when exposed to light and air. The
result depends largely upon the amount ingested. The other viruses
have proven even less satisfactory.
Under natural conditions these rat viruses may be likened to a
chemical poison, with the great disadvantage that they rapidly lose
their virulence and are comparatively expensive. They also have the
further disadvantage that chemical poisons do not possess of rendering
animals immune by the ingestion of amounts that are insufficient to
kill or by the ingestion of cultures that have lost their virulence.
PLAGUE ERADICATION IN CITIES BY SECTIONAL EXTERMINATION OF RATS AND
GENERAL RAT PROOFING.
By VICTOR G. HEISER,
_Passed assistant surgeon, U. S. Public Health and Marine-Hospital
Service, chief quarantine officer and director of health for the
Philippine Islands_.
The health officials of the city of Manila, P. I., for the five-year
period from 1900 to 1905 made most valiant efforts to destroy the rats
of the city; approximately $15,000 were paid in rat bounties and
$325,000 in salaries and wages and other expenses for rat catching,
but at the end of that time the rats were apparently as plentiful as
before and the plague was still present. The experience in Tokio and
Osaka had been practically the same. Professor Kitasato expressed the
opinion that a given city could only have up to a certain number
anyhow, because further increase was limited by the amount of
available food, and when the limit had been reached the rats commenced
to eat one another, which prevented more than a certain number ever
being present, and that the increase by breeding was about as rapid as
any method of destruction which had yet been tried.
The following plan was then tried, and the plague among human beings
soon disappeared, there being no cases since April, 1906; and it has
been eradicated among rats each time that it has made its appearance.
A list of the places at which plague-infected rats were found was
made. Each was regarded as a center of infection. Radiating lines,
usually five in number, were prolonged from this center, evenly spaced
like the spokes of a wheel. Rats were caught along these lines and
examined. Plague rats were seldom found more than a few blocks away.
The furthermost points at which infected rats were found were then
connected with a line, as is roughly shown in the diagram on page 206
(Fig. 59.)
The space inclosed by the dotted line was regarded as the section of
infection. The entire rat-catching force, which had heretofore been
employed throughout the city, was then concentrated along the border
of the infected section; that is, along the dotted line. They then
commenced to move toward the center, catching the rats as they closed
in. Behind them thorough rat proofing was carried out. One section
after another was treated in this way until they had all been wiped
out. Once weekly thereafter rats were caught in the previously
infected sections and at other places which were insanitary and which
had been infected in years gone by. This was continued for one year.
The city was then divided as is shown in the diagram facing this page,
and rats are caught once weekly at each point at which the lines
intersect and sent to the laboratory for examination.
[Illustration:
FIG. 59.—Isolated plague-infested center, Manila, P. I.
]
In addition, sanitary inspectors are instructed to bring in dead rats
which have evidently died of disease, and more detailed rat catchings
are made along the water front.
It is understood of course that rat proofing of the entire city should
be thoroughly carried out and constantly maintained.
CONCLUSIONS.
1. Since the above system was adopted plague has disappeared in the
city of Manila; among human beings in 1906; among rats in 1907, and it
has not reappeared since.
2. That the cost is only a small fraction of that of general rat
extermination.
3. That the plan is thoroughly practical for any kind of a city.
[Illustration:
FIG. 60.—General Scheme for testing plague rat infection, City of Manila.
Sanitary Map Bureau of Health. _Escala 1:38,500_
]
THE RAT IN RELATION TO SHIPPING.
By WILLIAM C. HOBDY,
_Passed Assistant Surgeon, Public Health and Marine-Hospital Service_.
Since men first went down to the sea in ships the rat’s voyage-making
tendencies have been known, and their fecundity is as well established
as their fondness for travel. The record does not state that there
were more than a pair on the ark at the beginning of her voyage, but
the chances are better than even that her skipper began that voyage
with more rats than his manifest showed; but whether he did or not, we
can be sure he had more at the end of the voyage than at the
beginning. Whether or not succeeding generations inherited from their
forbears on the ark this well-known wanderlust is undetermined, but it
is a fact that the intimacy and companionship established and begun
then have been persistently maintained by the rat ever since. His
travels have been coextensive with man’s, until to-day there is not a
port on earth where the rat is not present. Any exception to this
statement simply proves the rule. The rat is cute; he knows when he is
well off and his absence from a port does not prove that he has not
been there, but that he has been too intelligent to follow man ashore.
In establishing this shipboard intimacy there has been no “by your
leave” courtesy on his part either; he goes without consent—against
orders, even—and man’s ingenuity has as yet discovered no effective
means of keeping him off. This is not surprising when the rat’s
ability as a rope walker is considered. I have seen a rat gallop with
all appearance of enjoyment along an inclined electric cable from a
church steeple on one side of a street into the second story of a
hotel on the other. Others have been seen traveling along the
telephone wires from house to house, and on shipboard they frequently
have runways on small pipes along which they scurry in perfect
security. When a ship is fended off 6 feet from the dock and her gang
plank is lifted or guarded she is still freely accessible, because all
her mooring lines are only so many highways along which rats can and
do pass with ease and in perfect safety.
This fondness for ships and sea travel is shared by the various
species of the rat family, but the _Mus norvegicus_ has earned the
reputation of being the greatest traveler of them all. He almost
invariably predominated among those killed by fumigation on shipboard.
That he finds life on shipboard easy and the conditions satisfactory
is proved by the numbers that are destroyed from time to time by
fumigation. While in charge of the outgoing quarantine work in San
Francisco the chief engineer of a small lumber carrier called to book
his vessel for fumigation. The vessel was small, only 260 tons, and
carried nothing but lumber and her own ship’s stores, but the chief
declared she was overrun with rats, and to prove it showed where they
had eaten the patches from his shoes. He declared they robbed him of
his sandwich when he came off watch, and requested me to give her a
thorough fumigation. This was done. The next morning the agent of the
vessel phoned to ask how I measured rats, stating that on this vessel
they had collected “a barrelful and seven.” Three hundred and ten on a
little vessel of only 260 tons burthen.
On another vessel after one fumigation 100 were collected immediately
after fumigation, but a few days later, when the vessel was undergoing
extensive repairs, 425 others were found—a total of 525 on one small
vessel. These numbers are small, however, when compared with the
results obtained on others, i. e., on grain-carrying vessels. For
instance, a vessel was fumigated some years since in Bombay where
1,300 were destroyed at one time, and the _Minnehaha_, a new vessel
only nine months in commission, on fumigation in London, England, in
May, 1901, yielded a bag of 1,700 rats.
ADAPTABILITY OF THE RAT TO HIS SURROUNDINGS.
In addition to his qualities as a sailor and tight-rope walker, the
rat has the power of adapting himself to most unusual conditions and
surroundings. At the beginning of the outgoing work in San Francisco
it was urged that rats either could not or would not live on any part
of tank ships engaged exclusively in carrying oil, owing to the fumes
and vapors that permeated the entire vessel. This statement was
unquestionably correct for those compartments in which the oil itself
was stored or carried. It was not true, however, for the
superstructure of these vessels, for on one of the oil carriers 60
rats were found after one fumigation, and of the thirty or more
vessels of this class that were regularly fumigated in San Francisco,
although the odors of oil or gasoline were quite strong in the living
compartments, not one was found that did not harbor rats. Still more
remarkable, as illustrating the rat’s adaptability, was the fact that
from the large refrigerating plants which some vessels carried and in
which fumigation had not been practiced for a long time rats were
obtained that had grown a fur an inch and a half long to protect
themselves from the cold.
DAMAGE TO CARGO.
That rats on shipboard in any such numbers as mentioned above must do
much damage to cargo can not be doubted.
Inquiry as to the extent of this damage showed that there were no data
on the subject. That such damage was common and considerable, however,
was revealed by the fact, elicited by these inquiries, that nearly
every steamship company on both the Atlantic and Pacific took
precautions both to keep rats from getting on board and to destroy
them after they did. One example will show what damage may occur. The
British steamer _Gadsby_, on a voyage from India to Antwerp, covering
a period of twenty-nine days, had 44,000 out of 46,000 bags of wheat
cut by rats, with an estimated damage of $2,200.
The constant and almost universal presence, then, of rats on shipboard
can not be doubted, and if it could the results of fumigation,
wherever practiced with SO_{2}, would serve to settle the question,
for they are found under all conditions, even on the most unlikely
vessels.
How do these rodents gain access to a vessel? It has been the custom
to assume that they came on board from the docks over the side when
this was possible, and when it was not, as when the vessel was fended
off or stood too high out of the water, that they made use of the
gangways, mooring lines, hawsers, etc., as avenues of communication.
It is still the practice, therefore, in enforcing antirat precautions,
to compel the ship to fend off 6 feet from the dock, to wear fat
funnels on all lines, and to raise the gangway from the dock at night.
Just a word as to these precautions. The most practical fender is a
floating one made of heavy timbers either bolted together into a solid
frame, with the necessary cross braces bolted in, or made up of logs
or spars chained together. They should be long enough to distribute
the pressure of the vessel as the tide moves over a number of piers or
piles so that the weight does not bear, through the medium of these
fenders, on just one or two of the wharf foundations. Such a fender
will stay in position, will do no damage to the vessel, and no matter
how great the amplitude of the tide may be, will always remain below
the ship’s gunwale and can not therefore be utilized by rats as a
means to get on board. Large vessels require at least two. Small ones
need but one, and it was found in San Francisco, in the case of those
vessels changing their mooring several times daily, that this one
could be carried from wharf to wharf by the vessel without trouble or
delay simply by lashing it edgewise outside on top of the guard.
Funnels should be of heavy galvanized iron, circular in shape, and not
less than 36 inches in diameter. The spout of the funnel should be 3
inches in diameter and should be at least 18 inches long. The flange
of the funnel should be soldered to this 18-inch pipe at its middle so
that the spout projects 9 inches out of the funnel and 9 inches into
it. When the two halves of the funnel are brought together this spout
or tube is occupied by the line or hawser to be protected, and by
lashing this tube to the hawser the funnel is held in position and
prevented from lying down. Such a funnel should be put on every line
from the vessel to the dock, and when the tube does not fit the line
the latter should be parceled before the tube is lashed to it.