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26th An. Rpt., Bur. Animal Industry, U 8. Dept. Aor., 1909. PLATE I.



Fig. 1.— a Zebu Bull of the Borden Importation, in Quarantine.



Fig. 2.— Two Zebu Calves of the Borden Importation, in Quarantine.



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THE SBADICATION OF SUBBA. 85

The color of the Brahman cattle is chiefly light silver gray, with
dark shadings of the fore and hind quarters. (See PL II, fig. 1.)
However, the color varies much according to the breed, some being
red, while others are white, and the albino bulls constitute the so-
called sacred bulls of India, which play a very important part in
certain religious festivals. Among the Hindus the zebu is believed
to have a charmed life. They venerate this animal and hold its
slaughter to be a sin, though they have no scruples about working it.
While the Brahmans are classed as a distinct species, they cross
readily with our domestic animals. In India these animals are not
only reared for milk and flesh, but are also extensively employed as
beasts of burden. They are likewise used for both riding and driv-
ing, having great powers of endurance. The hump is considered the
most delicate part of the carcass for food, and is usually prepared in
pickle^ like tongue. The cows sometimes yield a fair amount of milk,
but it is low in butterf at.

APPEARANCE OF SUBRA IN THE UNITED STATES.

Despite the fact that the blood of all the Indian cattle in the
Borden importation had been examined microscopically on two occa-
sions at Poena, and twice again during the ocean voyage en route
to New York, with negative results, it was deemed advisable and a
necessary precaution to make the more exacting test of rabbit inocu-
lations before accepting the cattle as free from the surra parasite.

With this end in view a sufficient number of rabbits were taken
to Simonsons Island and one rabbit was inoculated with the blood
from each animal. Cover-glass preparations were likewise made at
the same time for examination of the fresh, unstained specimens?.
These blood inoculations were commenced on July 5 and 6 by the
inoculation of 49 rabbits with the blood of adult cattle, the two calves
not being tested at this time.

The method of taking the blood and injecting the rabbits for this
and all subsequent tests was as follows: Each zebu was secured by
a nose ring or halter to a head rail, the hair on the margin of the left
ear clipped, and the tissue toward the tip of the lower margin washed
and disinfected with carbolized water, dried, and the ear then
whipped by the hand to render the blood vessels turgid. A small
vessel near the margin was then nicked with the point of a knife and
5 to 8 c. c. of blood obtained in sterile bottles, each containing a
sufficient quantity of potassium citrate solution to prevent clotting.
When necessary the hemorrhage was arrested by the use of a figure-8
suture after sufficient blood had been obtained. After each opera-
tion the knife and hands of the operator were washed in a 5 per cent
solution of carbolic acid. Identification cards were made out for
each rabbit, to which a number was given corresponding to the nxmi-
*— 11 2



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86 26TH REPORT, BUREAU OF ANIMAL INDUSTRY.

ber of the animal from which the blood was taken, and 2 c. c. of this
blood was injected subcutaneously into the rabbit on the inner side of
the thigh. The syringe used for this purpose was disinfected after
each injection with 5 per cent carbolic acid and then rinsed with
sterile water.

A few days later the temperatures of the rabbits were taken.
Following the first inoculation tests, rabbits Nos. 16, 39, and 42
showed a marked rise. The blood of each rabbit was then examined
microscopically, and the Trypcmosoma evansi, the causative agent of
surra, was demonstrated on the ninth day in rabbit No. 16, and on
the tenth day in rabbits Nos. 39 and 42. (See fig. 2.)

It is our opinion, which appears to be confirmed by the following
notes, that in all probability there were only these three infected
zebus at the time of the arrival of the cattle in quarantine, and that
the others became subsequently infected by means of the plague of
flies present that summer in the vicinity of Staten Island.

The seriousness of the appearance of surra in the United States
being apparent to all interested parties, the question of preventing
the landing of any of the cattle was carefully considered, with the
result that it was finally decided to kill and bum all the infected
cattle and to make repeated blood tests of the remaining animals
under proper precautions until it was absolutely proven that the in-
fection had been entirely eradicated. As the importer, Mr. Borden,
was at that time in Texas, a delay of several days was occasioned
awaiting his arrival, but the killing and burning of the three infected
cattle was accomplished on July 20.

THE CAUSATIVE AGENT OF SXTBBA.

It has been definitely shown by numerous experimental observa-
tions that surra is caused by the presence of the T7ypano8oma evansi
in the blood. This fact was first reported by Dr. Griffith Evans
in 1880, and since then has been confirmed by many other investi-
gators. The parasite is a flagellate protozoan 20 to 30 /* long, 1 to
2 ft broad, and approximately spindle-shaped in outline. (See fig.
2.) Each organism has a somewhat pointed posterior extremity,
while the anterior extremity narrows into a long, wavy flagellum.
The organism moves, as a rule, with the flagellum end forward, owing
to the rapid lashing of this whip-like extremity and by the contrac-
tions and relaxations of the body. The micronucleus or blepharoplast
or centrosome is prominently located near the posterior end and is
connected with the flagellum by a distinct line passing along the free
border of the undulating membrane, which is along one side of the
parasite like a fin. The nucleus is near the anterior end. Multipli-
cation takes place by longitudinal division only, the centrosome being



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THE EBADICATION OF SUBEA. 87

the first to begin dividing. The division of the nucleus follows, as
a rule, the flagellum remaining attached to one of the resulting halves,
while a new flagellum develops on the other half.

The parasite is transmissible from infected to healthy animals by
biting flies, and perhaps by other agencies. Owing to its large size
and active motility it is readily detected in a film of fresh unstained
blood with the low-power lens of the microscope. At first there is
noticed an intermittent and characteristic agitation of some of the
red cells, and upon focusing in the vicinity of this motion there will
soon emerge to view a minute, eel-like organism two or three times as
long as the diameter of the red cell, actively moving between the
blood cells. It appears in the blood in swarms, so that the examina-
tion of the blood at one

time may give negative _^^S^r^

results, while a similar ex- W

amination made earlier or ^y^Jf v.,_ kJ

later may give positive ( /^ /O P**)

results. The organism, v^ Jw' /^/^

however, is invariably ^ vr*^^^-.^^ i /.^^

found during the parox- _^ .^ r^ ' ^^^ ^^

ysms of the disease in

both experimentally and ^.^ ^ ^^^^

naturally acquired surra. O ^-^ ^^ PS

When such blood is fil- OC\

tered through bougies the (^ (y Q ^b^ C3

filtrate is not pathogenic, \ f (T^C^^ ^^

proving that the trypano- \ / t^ ^

some is withheld by the V I ^J

filter. r^^ ^"^

The disease may like- f

wise be transmitted from ^'®- ^' — ^rVP<^no8oma evansi, the cause of surra.
,., , . , , (From Zebu No. 44.)

one susceptible annual to

another through a long series, and in each instance the trypanosome
may be observed during the febrile attack by microscopic examina-
tion. Even during the intermission when the blood appears to be
entirely free of the trypanosomes the inoculation of rabbits wiD, as a
rule, result in the production of the disease. All attempts that have
been made in the laboratory of the Pathological Division to cultivate
the organism on the blood-agar medium of Novy, as well as by other
methods, have been without result, although the cultivation of certain
other species of trypanosome (T. Uwisi and T. equiperdum) has been
accomplished.

The exact method by which these parasites interfere with the health
of the infected animals has not as yet been established.



louna aurmg tne parox- yi^_^ X\ ^^

ysms of the disease in P^p Qy 0^ yj

both experimentally and ' Q) ^



^.



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88 26TH REPOET, BXJBEAU OF ANIMAL INDUSTRY.

ITATUBB OF THE DISEASE.

The term " surra " was given to this disease by the natives of India,
and was adopted by Evans, Lingard, and others on account of its
appropriateness. The word " surra," by which the disease has since
been universally known, was used by the natives to describe anything
withered or rotten, such as a decayed carcass. They applied the
term loosely to all those chronic ailments of a devitalizing character
which had no specific designations. The name was thus very c(to-
prehensive, and was applied to this specific disease of animals be-
cause there is a marked withering or falling off in condition without
sufficient post-mortem lesions to account for it. It is a disease of the
Far East, and has prevailed in certain sections of India for genera-
tions. It has been reported from the Persian Gulf, Korea, Egypt,
Syria, Algeria, Zululand, Java, Borneo^ Madagascar, Mauritius,
Burma, China, the Philippine Islands, and other places.

Surra is a specific, cwnmunicable febrile disease occurring in
horses, mules, asses, camels, elephants, dogs, and rats, and capable of
being transmitted by inoculation to cattle, buffalo, sheep, goats, rab-
bits, guinea pigs, and monkeys. It is due to the presence of a specific
flagellate parasite in the blood, the Trypanosoma evansi^ named
after its discoverer. The fever is of an intermittent, remittent, and
sometimes relapsing type, and continues for varying periods from a
few days to months, depending upon the animal attacked and its
physical condition at the time. In solipeds the disease generally as-
sumes an acute type and causes death in a relatively short time, while
in camels the disease is of a chronic type and the animal may live
for months or even years, frequently recovering if the disease lasts
for three years. The blood of cattle may swarm with the trjrpano-
some without apparent harm, although the animals may become
very thin and anemic for a time, after which they, as a rule, recover,
though they occasionally die. The great danger from infected cattle,
however, is in the possibility of the infection being carried from the
apparently healthy cattle to the highly susceptible horse, mule, or ass
by flies or otherwise. The period of incubation is usually about six
to eight days after the exposure, although the disease may develop
in from two to seventy-five days.

All available evidence seems to indicate that the most common
method of transferring the trypanosome of surra from infected to
uninfected animals is by means of insects, particularly the biting
flies. Infection may likewise take place through an abraded wound
on the body becoming contaminated with infectious blood. Thus
dogs and cats with abrasions of the mucous membrane of the diges-
tive tract may contract the disease by eating the flesh of horses which
have died of surra. Saddle galls, summer sores, and similar lesions
on otherwise healthy horses may likewise become infected by birds



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26tm An. Rpt., Bur. Animal Industry, U. S. Dept. Aqr. , 1909. PLATE II.



Fia 1.— A Zebu Bull of the Borden Importation, on the Ranch in Texas.



Fig. 2.— a Zebu Bull whose Blood was Found to be Infected with the Trypanosome

OF Surra.



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26th An. Rpt., Bur. Animal Industry, U. S. Dept. Aqr. , 1909.. PLATE III.



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THE ERADICATION OF SURRA. 89

and insects which peck or feed on them after having previously
soiled' their' beaks or probosces on infected animials or carcasses.
Drinking stagnant water and eating grass or other forage grown on
recently inundated Jand are popularly regarded as being methods of
infection with surra, but the experimental proof to support such
opinions is lacking. Stiles has probably given the correct interpreta-
tion of this theory by drawing attention to the fact that biting flies
are generally numerous around inundated pastures and stagnant
water, and therefore a great number of possible transmitting agents
of the disease are in these localities.

In the outbreak of surra here recorded it was quite definitely
proved that the infectious principle was carried from animal to
animal by the large breeze fly, Tabanus atraheSj and by no other
species of fly or other kind of insect; nor did contact exposure, ttie
use of the same drinking buckets, etc., play any part in the spread of
the infection.

According to Lingard,* the chief symptoms in the horse are an in-
termittent, remittent, and sometimes a relapsing type of fever which
continues for a varying period from a few days to several months.
Closely following the first rise in temperature there is the occasional
appearance of urticarial eruption, which may make its appearance at
any time during the course of the disease. Then follows the presence
of petechise on the mucous membranes, chiefly those covering the
membrana nictitans; also nasal, ophthalmic, vaginal, and other
mucous discharges, and the exudation of a yellow semigelatinous
material in the subcutaneous and other connective tissues, especially
of the legs, breast, and abdomen. (See PI. III.) There is rapidly
advancing anemia, emaciation, and great debility, although in the
large majority of cases the appetite remains good throughout, no
matter how high the fever may be. There is extreme pallor of the
visible mucous membranes, followed at a later period by a yellow
tinge. From first to last there is a progressive wasting.

The blood at first presents a normal character, but after a vary-
ing period of time undergoes marked changes. The white corpuscles
are increased in number, while the red cells usually cease to form
normal rouleaus, lose their individuality, and run together, forming
irregular masses which are first of a dark appearance but gradually
beccHne pale owing to the loss of coloring matter as the disease
advances.

The presence of the flagellate is not continuous during the whole
course of the disease. At first it is usually found in small numbers
in the blood, but it increases with greater or less rapidity until, having
attained a maximum, it disappears either gradually or suddenly, to

^ Lingard, Alfred. Report on horse sarra. Bombay, 1893.



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90 26TH REPORT, BUREAU OF ANIMAL INDUSTRY.

reappear after an interval. The periods during which it may be
observed in the blood by microscopic examination are marked by ex-
treme irregularity, varying from one to six days, though the latter
number is very unusual.

The disease is invariably fatal in horses, death usually being due to
exliaustion, but sometimes to concurrent complications. After death
no specific lesion is present, but as a rule there are small subpleural,
subendocardial, and subperitoneal extravasations, together with en-
largement of the liver and spleen. If death takes place during a
paroxysm the hematozoan will be found for a certain time in the
blood. (See Lingard, 1893, pp. 1-2.) There is also an edematous
exudate into the cellular tissues of the legs and abdomen, and the
lymph glands are edematous and enlarged. The kidneys are con-
gested and edematous or the seat of blood extravasation. Gastric
ulcers have been noted preceded by capillary embolism and con-
gestion.

In cattle affected with this disease the trypanosomes are frequently
found in the blood before the animals show outward symptoms. (See
PI. II, fig. 2.) During this time, however, they serve as a means
of spreading the disease. It is interesting to notice that in cattle
the affection, unlike the affection in solipeds, is relatively benign,
and many cattle, after having the disease for a time, recover. The
first noticeable symptom is dullness followed by progressive emaciation
with slight temperature variations. Under the breast and abdomen
may be noted occasional areas of edema, accompanied by muco-
purulent inflammation of the conjunctiva, cornea, and nasal mucosa.
Lingard has stated that, although during the paroxysms of the dis-
ease the blood of the bovine species teems with the hematozoan, and
their bodies become extremely emaciated, nevertheless the cattle
usually recover from an attack and in time put on flesh and appear
in robust health.®

However, cattle seem to vary in susceptibility to the fatal effects
of sun-a in different countries. For instance, when surra was intro-
duced into the Island of Mauritius in 1901 by an importation of
Indian cattle, 70 to 80 per cent of the native cattle, it is said, later
succumbed to the disease. It must be remembered that in tropical
countries the transmitting agencies are present to some extent all the
year round, the disease being spread more actively during the rainy
season, owing to the larger number of flies present and to the humid
state of the atmosphere, which favors greater dissemination.

« For a detailed account of surra the reader is referred to Bureau of Animal
Industry Bulletin 42. or to the Fame article In the Eighteenth Annual Report of
the Bureau, entitled "An emergency report on surra."



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THE ERADICATION OF SUBBA. 91

PBOMPT EBADICATION OF THE DISEASR

As the decision had been made to destroy only those cattle of the
Borden importation which harbored the trypanosome of surra, the
first step taken after the killing and burning of the three infected
zebus was to protect the remaining cattle from the biting flies and
mosquitoes which swarmed around the corral in countless numbers.
Therefore on July 24 was commenced the flooring and screening of
that portion of the corral occupied by the cattle, and this work was
accomplished July 27.

While the inclosure was being screened the cattle were necessarily
removed from their original positions and placed temporarily in the
open along the north and west sides of the corral. On completion of
the screening of the south and east sides of the corral an abundant
supply of sticky and poisonous fly paper was spread about within the
inclosure, and very shortly all the Tabanus atratvs were caught or
destroyed, along with large numbers of the other Tabanidse and
StomoQsys calcitrans^ one of the Muscidee. However, a considerable
number of the latter species and a few T. lineola and T. costalis '
still remained, and it seemed impossible to eliminate them by this
temporary screening.

The second series of inoculations was made on July 31, the results
of which were anxiously awaited, as upon the outcome depended
the fate of the entire herd. The hope was entertained that if the
Tabanidae were solely responsible for the spread of the infection
(which dissemination was expected under the circumstances); there
were prospects of saving some of these valuable animals brought at
great risk and expense 10,000 miles over the seas. On the other hand,
should the other species of flies, which were far more numerous and
very difficult to eliminate, be found to be active disseminators of the
disease, the hopes of saving even one animal would have to be aban-
doned. On the expiration of this test, which gave seven reactions
(Nos. 48, 1, 2, 50, 34, 41, and 44), it was decided that it was possible
eventually to save part of the herd by placing each animal in an indi-
vidual fly-proof stall, and by eliminating the infected cattle by blood
inoculations of rabbits. After this second test it seemed plausible
to consider that only the Tabanidse — and probably only the Tabanus
atratua — ^were responsible for the spread of the infection, and that
the disease would be eradicated with the elimination of those animals
which had been infected by these flies previous to July 27, when this
Tabanvs was effectually excluded as a factor in the conveyance of the
infection.

A specially constructed fly-proof stable containing individual fly-
proof box stalls was therefore erected for the purpose of eliminating
all kinds of flies, and especially the stable fly, Stomoxya calcitrans^



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92



26TH REPORT, BUREAU OF ANIMAL INDUSTRY.



considered by some authorities as being capable of transmitting try-
panosomal infections. This stable was completed on August 15, by
working three shifts of carpenters, and during its construction the
third (August 6) and fourth (August 11) tests had been made,
resulting in the reaction of four animals in each test

The appended table shows the positive results of the blood inocu-
lations.

Positive refactions of rabbits to surra, follotcing inoculaiUms tcith blood of zebus.



I



Date of inoculation.



I No. of
animal.



Fint test, July 6 and 6.
Second test, July 81

Third test, August 6a. .
FDurtb test, August lib.



Date of
diagno-
sis.



July 16
July 16
...do....

Aug. 6
Aug. 7

...do

...do....
Aug. 9

...do

...do....

Aug. 11
Aug. 12

...do

Aug. 15

...do....
Aug. 16
Aug. 18
Aug. 20



Period of incuba-
tion.



Ninth day.

Tenth day.

Do.

Sixth day.
Seventh day.

Do.

Do.
Ninth day.

Do.

Do.

Fifth day.
Sixth day.

Do.
Ninth day.

Fourth day.
Fifth day.
Seventh day.
Ninth day.



• In addition to those recorded in this test, Nos. 1, 43, and 44 repeated their reactions
of the second test, while rabbit No. 50 died before trypanosomes were found. Nos 2, 34,
and 41 did not repeat in the third test.

^ Besides these original reactions in the fourth test, Nos. 6, 26, and 47 of the preceding
test repeated, while rabbit No. 40 died on August 22 without showing any trypanosomes.
These unintentional retests occurred in the third and fourth series owing to the inocula-
tions being made so close together that the rabbits in the preceding test had not time to
react before the next series was injected.

The cattle shown to be infected with surra by these reactions in
the inoculated rabbits were destroyed immediately upon the recog-
nition of the trypanosome in the rabbits' blood. Owing to heavy
rains several of the cattle were buried instead of burned, their bodies
being destroyed by covering with unslaked lime and pure sulphuric
acid, but in no instance was a post-mortem examination permitted,
on account of the danger of disseminating the infection.

On August 15 the remaining cattle were removed from the screened
corral and placed in the individual fly-proof box stalls within the
fly-proof stable already mentioned. No further inoculations were
made until August 31 ; a test made then, and subsequent inoculations
made September 7, 13, and 20, and October 10, 19, and 24, proved
negative in every case. On September 7 rabbit No. 48 exhibited a
pseudo reaction, due, as was demonstrated later, to an intercurrent
disease.

In the inoculations confirmatory tests were not made prior to
August 15, owing to the danger involved in keeping the infected



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XHB BBAPICATIOK OF SURBA. 98

cattle alive; but it waa noted that several catUe— for instance Nob.
2, 34, and 41 — failed to repeat in giving reactions on the 9ubeaquent
nnintentional retest. These retests occurred in several instances
where two series of inoculations were made ao close together that the
rabbits in the first test had not time to react before the next series
was injected.

During the quarantine no reliance was placed upon the micro-
scopic examination of blood smears made direct from the cattle, but
it will be interesting to note that in two cattle numerous trypanosomes
were observed by this method of examination. As the disease spread,
the average period of incubation in the rabbits was shortened, and
those rabbits which were not immediately killed upon reacting soon
succumbed to the infection. Guinea pigs were also used in some of
the tests, but proved unsatisfactory as compared to rabbits.

In view of ^e fact that the last seven series of tests were succesaveljr



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