Hog cholera and anti-hog cholera serum

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Cornell University Library
SF 973.M64

Hog cholera and anti-hog cholera serum.

3 1924 000 260 301

LIBRARY

NEW YORK STATE VETERINARY COLLEGE

ITHACA, NEW YORK

THIS BOOK IS THE GIFT OF

T'co'\ft.%%0\- d^ TWero^Y CAAign, ^STftnW Aift'|v*a.\g Imifi,

State Veteeixary College. 95

HOG CHOLERA AND ANTI-HOG CHOLERA SERUM.

H. J. 'Milks.
Department of Materia Medica and Small Animal Clinic.

The importance of '' Hog Cholera " and the production of anti-
hog eholera serum to the live stock interests of the State will be
readily seen when one considers that according to the year book
of the United States Department of Agriculture for 1910, there
were 656,000 hogs in the State with a value of $7,5i4,000. There
has always been doubt as to whether the highly infectious disease
hog cholera existed in the State or whether the reported outbreaks
of cholera were not caused by some dietary condition as, for in-
stance, Moore has pointed out in the case of feeding swill which
contained large quantities of powdered soap.

However, after the discovery that a filterable virus is the cause
of the|epizootic disease and not the bacillus of hog cholera, it was
suggested that some of the outbreaks of apparently infectious
diseases of swine from which this latter organism could not be
isolated might be due to the filterable virus. With this in view,
several inoculations were made with the filtered blood of animals
which had died of supposed hog cholera. The result of this work
proves , conclusively that hog cholera exists in four counties of
the State and there is good evidence that it is present in other
localities.

. Historically it is interesting to note that hog cholera has existed
in this country for a long time. It was first reported from Ohio
in 1833 and was thought by American authorities to have been
imported from Europe. Scientists on that continent, however,
denied its existence in Europe until long after its appearance
here. The absence of positive diagnosis at that time failed to
make clear in which country it originated. It is reasonably cer-
tain, however, that Ohio was the first state to be infected. During
the next twenty years after its first appearance there were over
ninety outbreaks divided among several states and furnishing
centers from which the infection has been carried to practically
ever state in the Union.

Dr. Geo. Sutton of Aurora, Ind., made the first report upon
the disease in 1853. This was followed by reports by E. M. Snow
of Providence, R. I., in 1861, Dr. James Law, Ithaca, N. T., in
1875, and Dr. Detmers in 1877. Dr. Law's re^p^rt coiitains, the

96 Annual Eepoet of the

first fairly accurate and complete description of the disease. The
work of these men covered the symptoms of the disease and the
post-mortem appearance of the organs of animals that had died of
it, in fact all that could be learned from field observation alone.
In 1878, Congress made an appropriation for the investigation
of swine diseases, ^ine men were appointed for the investiga-
tion of ISTS, and these for a period of two months only. Con-
sequently little was accomplished. The researches of these men
were to be made in the field and various measures applicable to
the control of epizootic di eases were tried. The results of these
investigations were summed tip as follows in a publication of the
Bureau of Animal Industry, 1889, Hog Cholera:

1. Swine diseases were found destructive in the most widely
separated districts of the countrjr.

2. The symptoms and post-mortem lesions were similar to those
described by Sutton, Snow, Law, and others.

3. Xo evidence was discovered to show that there was more
than one disease which prevailed as an epizootic.

1. It was believed that the outbreaks were due to a contagion
and that the disease was communicable.

5. The remedies tested were either without effect or of doubt-
ful value ill the treatment of affected animals or guarding against
the contagion.

Of the nine investigators only Law and Detmers retained their
appointment longer than two months. These men did consider-
able laboratory work. Law made inoculations into rabbits, rats
and sheep and seemed to establish the communicability of the
disease he investigated. Detmers, by the aid of the microscope,
thought he had discovered the cause of the disease and naiked the
organism Bacillus siiis. Both of these conclusiofis were in error
but pointed out the need of bacteriological research and careful
laboratory work as the only means of determining the cause and
prevention of the disease. Law and Detmers continued their in-
vestigation for the Department of Agriculture in 1879. In 1880
Salmon was added. Law devoted much of his time to the produc-
tion of a vaccine by attenuation of the virus or cause of the
disease. In this he was unsuccessful. During this time Detmers
continued his investigation with the microscope. During the next
four years little was done in investigation because it was under-
stood that it had been carried about as far as possible under
the methods then emplo^'ed and because of a lack of facilities
for and clear methods of bacteriological research.

State Vetetiinaky College. 97

In 1885 it was amioiinced that Salmon and Smith had dis-
covered the cause of the disease. This was determined as due
to a motile rod, to which the name has been given Bacillus cJwlerae
^uis or hog cholera bacillus. These investigators showed that
this organism was found in the organs of most of the animals
which they had examined that died of cholera. Further, they
■could produce symptoms similar to hog cholera and lesions, in
many cases, indistinguishable from those of animals that had con-
tracted the disease naturally. They were also able to recover the
bacillus from the animals which had died as the result of the
inoculation.

In 1886, Smith described an entirely different infectious dis-
ease of swine due to an organism belonging to the present Septi-
caemia Plaemorrhagica group. Accordingly, it was considered
that there were two distinct infectious diseases: hog cholera in
which the lesions were largely in the digestive tract, and swine
plague in which the lungs were mostly involved. In many out-
breaks they were able to find both diseases present and to recover
both organisms from the same animal.

The results of Salmon and Smith were confirmed by scientists
■of this and other countries and it was generally conceded that
there were two contagious diseases of swine, namely hog cholera
.and swine plague.

Since Bacillus cJiolerae suis was announced as being the cause
of hog cholera, the work has been largely to find a vaccine or
•serum which would serve as a preventive for the disease. Various
vaccines and sera were tried but none of the preparations gave
satisfactory or practical results. It was not imtil about twenty
years later that de Schweinitz was led to the suspicion that
B. cholerae suis was not the cause of the epizootic form of the
'disease. He noticed that although hog cholera is very contagious
and spreads readily to other members of the herd when once it is
introduced, yet when an animal was injected with pure cultures
■of B. cholerae suis, in many cases the animal would become sick
and die from the effects of the injection, but other animals asso-
ciating with it would remain well. He also found that it was
difficult to produce hog cholera by subcutaneous injections of
•cultures of the hog cholera bacillus, while the injection of some
of the blood of a sick animal siibcutaneously into a sound one
would produce the disease. Other reasons were that although
made immune to pure cultures of the hog cholera bacillus, animals
4

OS Anxual EhfO^Tt of thi;

were by no means immune when exposed to animals sick witb
cholera.

These facts led to further investigation. In 1903- de Schweinitz
and Dorset (Circular 41, B. A. I.) reported that B. cholerae suis
was not the specific cause of the epizootic disease, but that the
cause was a filterable virus or one so small that it could be passed
through the finest porcelain filter. It might be' well to add a word
relative to the term '' filterable virus." There are? certain diseases,
for instance rinderpest and foot-and-mouth disease, that are
highly contagious, and which are due to invisible organisms or
viruses present in the blood and fluids of the body. These viruses
are so small that they can be passed through the finest porcelain
filter and are invisible even with our strongest microscopes.

As a result of experiments published in 1805 (B. A. I. Bul-
letin 'Ko. 72i), it was determined that the filterable virus is the
real cause of the epizootic disease of swine j that the hog cholera
and swine plague bacteria are, so far as the epizootics are con-
cerned, secondary invaders. The fact, however, must not be lost
sight of that Bacillus cholerae suis and Bacterium septicaemia
haemorrJiagica are the cause of certain diseases of swine, and in
m^any outbreaks they exert considerable influence as to the mani-
festations of the disease.

Means hy which the infection is spread. Hog cholera may
be spread from a single center of infection in many ways. One
of the most prevalent is the purchase of a hog from an infected
herd and placing it in a sound one. It is also spread to some
extent by taking the sows from a sound herd to an infected herd
for service. This has occurred once in our experience in which
we had a clear history. The infection may also be carried from
one farm to another upon the attendant's shoes or upon the wheels
of wagons driven through an infected territory. Horses and cattle
though not capable of contracting the disease may carry the in-
fection from one place to another upon their feet. This also holds
good in the case of dogs feeding upon carcasses dead of the dis-
ease. Furthermore, it may be carried down a stream of water
from pollution higher up.

Period of incubation. The period of incubation varies from a
few days to two or even three weeks. This depends a great deal
upon the method of exposure, virulence of the virus, and resist-
ance of the animals exposed. Young and pampered animals are
usually more susceptible and have the more acute form of the

State Veteeinaey College. 99

disease. A short period of incubation usually means a virulent
type of the disease. As in the case of most infections, the virus
•of hog cholera is more virulent in the earlier part of an outbreak
■of the disease and may become so v^eak that the resistant animals
may not become affected at all.

Symptoms. The symptoms of hog cholera are not very charac-
teristic. Fever is usually present and in animals that are coming
down -with the disease, which have not as yet shown any symptoms
•of siclcness, the temperature may be several degrees above normal,
frequently it is subnormal in the last stages of the disease. Soon
.after being attacked the animal loses appetite, becomes weak and
may have convulsions. In the early part of an outbreak, the
yoimg and very fat animals may succumb without showing any
symptoms of sickness. Diarrhoea may be present and usually
follows constipation, although constipation sometimes persists
throughout the disease.

The symptoms vary somewhat with the virulence of the out-
break and the resistance of the animals attacked. If the virulence
is high and the resistance low the acute form is seen. In this
type of the disease, the animal shows fever, dullness, stiffness,
soreness, tremors, weakness, and loss of appetite. It does not
move unless made to do so ; in general there is great depression.
The eyes are inflamed and the lids gummed with the secretions.
Hed patches usually appear upon the skin, especially in the region
■of the ears, lower jaw, abdomen and inside of the legs. Some-
times the redness is d^^ffuse, covering the entire regions mentioned.
Before death this may turn to a purplish color. Coughing, rapid
breathing, and other symptoms of respiratory derangement may
be present but usually these symptoms are not pronounced until
shortly before death.

In the chronic type of the disease 'about the same symptoms are
•exhibited as in the acute except that the illness may last several
weeks or months, during which there is the usual weakness, loss
of appetite, inflammation of the eyes, and usually profuse diar-
rhoea. If these cases recover they are rarely of any value to the
owner. It will be noticed from the above description that there
are no symptoms characteristic of the disease. However, if an
animal or two have died and then after an interval of a week or
ten days others become affected in a similar manner, there is
sufficient grounds for suspecting the presence of hog cholera.

100 AxxuAL Eepoet of the

Post mortem ajypearances. There may be reddi&h or purplish
spots upon the skin or the entire region mentioned under symp-
toms may be colored. Petechiae may be present upon the surface
of the heart and occasionally on the pericardium and lungs. Fre-
quently pneumonia is present but is not so characteristic as the
small hemorrhages. In acute cases the spleen is usually enlarged,
dark colored, soft, filled with blood, and may show hemorrhages
beneath its capsule. In chronic- cases this enlargement is not
noticed and the color is often lighter than normal.

The lymph glands in the ingaiinal region are swollen and red
or even dark in color in the acute form of the disease. Those in
other parts of the body, mesenteric, angles of the jaw, etc., may
be affected in a similar manner. These lesions are not often found
in chronic cases. The kidneys in the acute disease are usually
the seat of small hemorrhages. To observe the condition of the
kidneys it is necessary to remove the capsule. If the kidnej's are
slit open hemorrhages of a similar nature may be seen on their
inner siirfaces. The color of the kidneys is usually darker than
normal and the hemorrhages may vary in size from a mere point
up to the size of a pin head.

Sometimes petechiae are foiind on the serous side of the stomach
and small intestine. The mucosae of these organs may also show
hemorrhages. The large intestine, however, is usually the seat
of extensive lesions. In the acute form of the disease hemor-
rhages may be present on both stirfaces of this organ. Erosion of
the mucous membrane is also common. The mucosa may be blood
stained ■ and the contents of the bowel blood stained from the
extravasation of blood. In the chronic form of the disease, thc-
so-called " button ulcers " may be found. These ulcers are usually
found in the caecum upon or near the ileo-caecal valve and are
quite characteristic of the disease. They are circular, hard,
yellow in color, with a darker greenish yellow center, raised dis-
tinctly above the healthy mucous membrane. They vary in size
from mere points to an inch in diameter and are so numerous in
some cases that large portions of the organ are destroyed. If the
ulcers are found diagnosis can be made fairly accurately, al-
though there is no other disease in this country in which the
petechiae are found in the heart, lungs, kidneys and other organs.

Any or all of the above described lesions may be found in an
animal dead of cholera, but only an occasional animal exhibits
all the lesions. For instance, it is practically impossible to find

State Veteeinaey College. 101

the button-like ulcers in the acute form of the disease and but
rarely are the hemorrhages seen in the chronic type.

Diag-nosis. Before diagnosing a disease as hog cholera there
are a few important factors one should bear in mind. In the
first place, is the disease contagious? That is, can it be spread
from one animal to another? Then the symptoms and post-
mortem lesions should be considered. It is possible to get a fairly
good idea relative to the disease from these observations but
m order to prove conclusively that the disease is hog cholera, it
is necessary to produce the disease in a sound animal by inocu.-
lating it with some of the filtered blood of a dead or very sick
animal.

The disease must be distinguished from sickness due to im-
proper feeding, especially in case of swill or garbage fed animab,
as it has been shown by Moore that powdered soaps used in wash-
ing dishes may cause a disease which resembles cholera. Of
course disorders due to dietary conditions would not spread as an
epizootic, while hog cholera would most likely spread throughout
the neighborhood. There are so very few other diseases which
might be confused with cholera that time will not be taken to
discuss them.

Treatment and prevention. There is no successful treatment
for hogs sick with cholera. Various products have been recom-
mended for this purpose but are of no practical value. The only
rational method of dealing with an epizootic is to prevent the
spread of the infection instead of attempting to cure those animals
already sick. Since there can be no cholera without the filterable
virus, every precaution shoiild be taken to prevent its being
carried to sound herds. After the disease has appeared in a herd,
the only known remedy that will prevent its spread is the Dorset-
jSTiles anti-hog cholera serum. This preparation will prevent the
infection of other members of the herd if used in the early part
of an epizootic. Besides administering serum the pens, troughs,
and yards should be thoroughly cleaned and disinfected, so that
the infection will not be carried to other places.

Production of the serum. Since the filterable virus could not
be grown artificially, it was necessary to resort to the blood of
hogs sick with cholera for any protective agent. On this account
many attempts were made to produce a vaccine by attenuating
the blood of sick animals. The results obtained by such attenua-
tion were too uncertain for general use. While endeavoring to

102 Annual Eepoet of the

produce a vaccine, it was noticed that by injecting an immune
animal with large amounts of virulent blood, a serum of high
protective powers could be obtained. (E. A. I. Bulletin Xo. 102,
Dorset, -McBi-ide, Niles.)

In order to produce anti-hog cholera serum it is necessary to
have an immune animal. Tor this purpose a pig is immunized
by inoculation with a few centimeters of virulent blood and an
injection of anti-hog cholera serum in opposite sides of the body.
Then the immune is hyperimmunized by the injection of large
quantities of virulent blood. The large amounts of virulent blood
required are obtained as follows : A few centimeters of virulent
blood are injected into susceptible pigs. When these animals are
in the last stages of the disease, they are bled under antiseptic
conditions, the blood deiibrinated by shaking with glass beads, and
strained through sterile gauze. To produce potent serum a strong
virus is necessary, that is, one that kills quickly. Otherwise the
serum produced would be weak in protective properties. We may
hyperimmunize in any of the following ways :

1. <Slow subcutaneous. Inject the immune animal soibcutane-
ously with 1 cc. per pound of body weight, In from seven to
ten days repeat the injection using 2^2 ce. per pound. Then after
the same interval inject 5 cc. per pound.

2. Quick subcutaneous. Inject 10 cc. per pound of body
weight.

3. Intravenous. Inject intravenously 5 cc. per pound.

4. Intra-abdominal. Inject intra-abdominally 10 cc. per pound
of body weight.

As soon as the animal has recovered from the effects of the
injection or the last injection, if the slow subcutaneous method
has been used, it is ready to begin bleeding from the tail. This
is usually within ten days. The bleeding is repeated at intervals
of a week for three or four bleedings. The animal is then killed
and all its blood used, or it may be rehyperimmunized. In re-
hyperimmunizing the animal usually receives half the previous
dose of virulent blood. Four or iive cubic centimeters of blood
per pound of body weight are usually taken at each bleeding.
Sometimes an animal will not bleed so much and occasionally it
is possible to take more. A two hundred pound hog will, in most
cases, give 800 to 1,000 cc. of blood at each bleeding.

Treatment of the Mood. The blood is drawn from the tail imder
as antiseptic precautions as possible. It is then deiibrinated or the

.State Veteeinaey ' College. 103

•clots broken up by shaking with glass beads, then strained through
sterile gauze to remove the clots. One half per cent, of phenol is
-added and the serum is ready for use. The blood of each animal
is kept separate and that of each bleeding added. The mixed blood
of several animals is tested before using.

Testing the serum. The following methods of standardizing
hog cholera virus and testing the potency of the serum were
adopted at a conference of the federal and State official^, in
December, 19'09 :

1. The standardization of hog cholera virus which is used for
, ihy per immunization.

a. Inject at least two pigs intramuscularly, giving each 2 cc.
■of the defibrinated diseased blood which is to be tested. The
Wood should not be more than 24 hours old and should have been
-kept at a temperature not higher than 55° F.

b. The test pigs should not weigh less than 50 pounds each.
After injection they should be placed in a small disinfected pen
•with at least one susceptible uninoculated pig of the same weight
and preferably of the same litter.

c. The virus shall not be considered suitable for use unless the
inoculated pigs become visibly ill within eight days and die within
fifteen days after inoculation. The carcasses of these pigs must
nshow undoubted lesions of hog cholera. Furthermore, the com-
municability of the disease induced by the blood inoculations must
l3e demonstrated by the contraction of the disease by the check
pig within 12 days after the appearance of the disease in the
inoculated pigs.

2. Handling the Mood used for hyperi/mmunization. The
diseased blood should be collected and manipulated under -.trict
antiseptic precautions, stored at a temperature not higher than
55° F. and used within 24 hours after drawing. It is recom-
mended that defibrination be postponed until immediately before
use of the blood.

3. Testing the potency of the hyperimmune serum.

a. If the plan of testing the mixed bleedings of each hyper-
immune be adopted by the producer, then we recommend that the
test be carried out as follows:

Inoculate three hogs, each weighing from 50 to 100 pounds,
vs^ith 2 cc. each of virulent blood. Inject two of these simiil-
taneously with 15 cc. each of the serum to be tested. If the hog
receiving virulent blood only sickens with hog cholera within

104 Annual Repoet ov the

eight, clays and is apparently ready to die in fifteen days, while-
the two receiving immunizing serum continue in good health, then
the serum may be considered suitable for field use in doses of
20 cc. for hogs weighing from 50 to 100 pounds.

b. If the plan of testing the mixed sera of several hyper-
immunes be adopted by the producer^ then inject intra-musctilarly
nine similar pigs weighing between 50 and 100 pounds each with
2- cc. each of virulent blood. Give each of three of these 15 cc.
of the immunizing serum to be tested. Give each of three others-
20 cc. of the serum to be tested. If all of those receiving im-
munizing serum remain in good health and two or more of the
checks become ill of cholera within eight days and are apparently
going to die in fifteen days, the serum shall be considered suitable
for field use in doses of 20 cc. for hogs weighing from 50 to ICO
pounds. If one or more of the pigs receiving 15 cc. of serum
become obviously sick of cholera and the three pigs receiving
20 cc. each of immimizing serum all continue to remain in good
health, then the serum may be used in field work, in increased!
doses.

Methods of using the serum. There are two methods of using
the serum. By the simultaneous method a dose of serum and a
small amount of virulent blood are injected in opposite sides of
the body. This method of vaccination is said to produce an
immunity that will last for life. It is to be preferred in cases
of well herds or in those that will not be exposed to the disease
for several months. This involves the use of virulent blood which
if handled carelessly may furnish the source of infection to sound
herds.

Serum only is injected in the other method. This serum will
produce an immunity that will last for several weeks or months,
but if the animals are not exposed to cholera within a few weeks
after receiving the serum, the immunity lessens and the animal
may again be susceptible to cholera. If, however, the animals are
exposed to the infection within a few weeks after receiving the
serum, the immunity is believed to be of a lasting duration. In
either case the injection is usually made in the inside of the thigh.
Serum will be supplied from this college for use in the latter
method only, since in most cases it will not be applied for imless
cholera exists in a herd. In this ease all the well animals may
be treated. ]^atural exposure to the infection takes place in these
cases and the virus is not needed. The serum should be ad-

State Veteeixaey College. 105

ministered by a competent veterinarian under strict antiseptic
precautions.

Dose and cost of serum. Animals weighing from 50 to 100
pounds are taken as the standard. The dose for such animals is
20 cc. Suckling pigs shoiild receive from 10 to 15 cc. Older
and heavier animals may receive as much as 30, 40 or even 60 cc,
in case of very large animals. If the herd is badly infected the
dose can be increased somewhat. It is a good plan to take the
temperatures of the animals treated and give a larger dose to
those having fever.

The cost of the serum will be $.25 per dose of 20 cc. This
amount partially covers the cost of production.

How to order serum. In ordering serum the foUowinginforma-
tion should be given : Number of animals, weight, length of time
■the disease has been in the herd, number of animals that have
died, number of those sick at the present time. Before ordering
serum, it should be always considered that anti-hog cholera serum
is not regarded as a curative agent but as a preventive and if
used in the early part of an epizootic it will prevent the infection
of the well animals. The serum will be of absolutely no beneiit in
any other disease than that caused by the filterable virus. Con-
sequently to avoid useless expense and disappointment, it ii neces-
sary to have the disease diagnosed by a competent veterinarian.
We would much prefer that the name of the veterinarian who
diagnosed the disease and who will administer the serum accom-
pany the order.

Outbreaks of hog cholera in the State. The following outbreaks
of cholera were studied and will be named simply from the county
in which they occurred.

. No. 1. Broome county. Early in the fall of 1909 attention
was called to a disease among hogs in Broome county. This herd
had consisted of about 200 animals. Of these, fifty or sixty had
died during the first four weeks of the epizootic. It was im-
possible to trace the source of the infection, as no animals had
been brought into the herd recently nor had any disease been
reported in the neighborhood. About fourteen years previously,
there had been a similar disease among the animals but no trouble
since. This outbreak was finally controlled by proper sanitary
measures, including the removal of the well animals to new
quarters, disinfection of the old quarters and proper disposal of
the dead animals.

Blood from a pig that had died at this place was filtered and
injected into a sound pig. This animal developed hog cholera and

106 Annual Eepoet of the

•died within a few days. Filtered blood from this animal was
injected into another sound one and in like manner caused sick-
ness and death. Blood from this animal caused sickness a:id
death in a third and in like manner filtered blood from the third
caused death of the fourth. All the inoculated animals showed
symptoms and lesions of hog cholera.

Na. 2. Cayuga county. November 28, 1909, a sick hog was
Teceived from Cayuga county. It was in a dying condition when
received. It was killed and the autopsy showed lesions of hog
cholera. Before it was killed, blood was drawn from its tail,
filtered .and used to inoculate another animal. The inoculated
animal died as a result of the inoculation with lesions of cholera.

No. 3. Tompkins county. No. 1. October 17, 1910, a sow
weighing about 200 pounds was brought to the clinic for examina-
tion. She was exhibiting symptoms of cholera (purplish dis-
■colorations of the skin, difiicult breathing, weakness, and chills).
This animal grew rapidly worse and died during the morning of
the 19th. Autopsy gave lesions typical of cholera. Cultures were
made from most of the organs of the body but no growth took
place except in those made from the kidneys, liver and lung from
which pure cultures of a streptococcus were obtained. Blood
from this animal was filtered and injected into two susceptible
pigs. Both of these animals died as a result of the inoculation,
showing typical symptoms and lesions of hog cholera.

The history of the outbreak on this particular farm is very
■clear. October 3d, the sow referred to above, together with two
others, were taken to a neighboring farm to be bred. One of
them was taken home immediately, the other two were left until
October 8th, when they were returned and placed with the herd
of sixteen animals. October 16th, the sow was first noticed to be
ill. Within a day or two, the other animal which had remained
the longer time became ill. This herd was treated with serum
and the results will be given later. It was learned after the
animals became ill that there was a fatal disease among the hogs
on the farm where these animals were taken for service.

No. 4r. Onondaga county. October 29, 1910, two dead pigs
were received from Onondaga county. These animals had been
killed when in a dying condition. On this account enough blood
could not be obtained for inoculation purposes. However, a few
cc. of abdominal fluid were obtained. This was diluted, filtered
and used to inoculate a pig but it did not produce the disease in
this animal. Of the two animals received, one exhibited typical

State 'Yeteeinaey College.

lOT

lesions of cholera while the organs of the other did not show any
pathological changes.

No. 5. Tompkins county. No. 2. December 5th, two pigs were-
ibrought for diagnosis. One was already dead and the other in
had condition. Autopsy of the dead animal gave typical lesions-
of cholera. The second pig did not die until December 13th. On
autopsy this animal showed a few lesions in the kidneys and
mesenteric lymph glands with typical button ulcers in the large
intestine. Another pig from this place was presented December
11th, and upon autopsy exhibited typical lesions of the disease.
jSTo inoculations were made, as the autopsies revealed characteristic-
lesions.

Hog cholera has also been reported from Oneida county.
Serum has been sent to this place and the reports of the results
obtained tend to confirm the correctness of the report.

In all eight animals were inoculated with the filtered blood
from suspected outbreaks of the disease. Seven autopsies were
made of animals from infected herds. From the investigation of
the disease of swine, hog cholera has been positively identified in
six herds distributed in five counties : Broome, Cayuga, Oneida,
Onondaga, Tompkins (2).

The following table gives the result of the inoculations of
filtered blood from suspected outbreaks of the disease:

Table ISTo. 1.—

Table of Inoculations.

No.

Date.

Dose.

Source of
infection.

Results.

Lesions.

Remarks.

1

19G9.
Sept. 28

lOcc.

Broome county..

Died Nov. 3 . . . .

Lungs, mesenteric
lymph glands,
kidneys, bladder.

Abscess at
point of in-
oculation.

2

Nov. 3.

3cc. .

Pig No. 1

Died Nov. 12 . . .

Lungs, mesenteric
lymph glands,
kidneys.

3

Nov. 12

3cc. .

Pig No. 2

Killed in dyinp
condition. Nov. 27

Kidneys, mesenteric
lymph glands.

'

4

Nov. 30

5oc..

Pig No. 3

Died Dec. 7 . . . .

Kidnes'S, lungs, me-
senteric lymph
glands.

5

Nov. 30

5cc..

Cayuga county. .

Died Dec. 15... .

Skin, pleura, lungs,
heart, kidneys,
lymph glands.

6

1910.
Oct. 22

3cc. .

Tompkins No. 1.

Died Nov. 10-. . .

Kidneys, bladder,
sra.all intestine.

7

Oct. 22

3cc. .

Tompkins No. 1 .

Died Nov. IS. . .

Kidneys, bladder,
spleen, mesen-
teric glands.

.8

Oct. 31

3cc. .

Onondaga county

dominal
fluid used.

108 AiS'xuAL Eepoet 'of the

Table ISTo. 2 shows the lesions found in animals sent in for
Table jSTo. 2. — Lesions.

diagnosis.

No.

Date
received.

Source.

Organs showing lesions.

Remarks.

1

Nov. 28, 1909

Cayuga Co . . .

Kidneys, lungs, mesenteric Ijinph
glands.

2

Oct. 17, 1910

Tompkins Co.
No. 1.

Kidneys, lungs, heart, skin, lymph
glands.

3

Oct. 29, 1910

Onondaga Co.

No lesions found.

4

O.t. 29, 1910

Onondaga Co .

Kidneys, lymph glands, bladder, lungs

5

Dec. 5, 1910

Tompkins Co.

No. 2.

Kidneys, skin, heart, lungs, lymph
glands, intestines, bladder.

G

Dec. 5, 1910

Tompkins Co.
No. 2.

Lungs, mesenteric glands, intestines. .

Ulcers in large
intestine.

y

Dec. 11, 1910

Tompkins Co.
No. 2.

in large intest.

After it was determined without doubt that hog cholera existed
in the State and after a favorable expression from many promi-
nent swine breeders of the State, the production of the anti-hog
cholera serum was undertaken. The serum has been produced
upon a limited basis only, since it was impossible to ascertain any
idea of the extent of the disease or demand for the serum. Ten
hundred and ninety^five doses, or 21,'90O cc, of serum have been
produced. At times the demand has been so great that it could
not be supplied promptly. Four hundred doses, or 8,100 cc, have
been sent out, leaving 695 doses, or 13,800 cc, on hand. It seems
reasonable to suppose that the demand will be much greater when
it is widely known that serum can be obtained at the college. It
is impossible to ascertain from our work an approximate cost of
serum. Simply calculating the number of pigs required to pro-
duce a certain amount of serum, for instance sufficient to
immunize 150 pigs, will require by the quick subcutaneous, slow
subcutaneous, or intra-abdominal method, one 100-pound pig and_
two 50-pound pigs; by the intravenous method, one 100-pound
pig and one 50-pound pig. This does not make allowance for
unavoidable loss of -pigs by death in the process of preparing the
serrmi. A fair estimate would seem to be that to produce enoughi
serum to immunize 150 pigs would require four animals of the
above size.

Results of the use of the serum. The first herd treated was the
one described as Tompkins county Xo. 1. The eighteen animals

State Veteeixaey College. 109

of this herd were treated October 19, three days after appearance
of disease among the animals and eleven days after the exposed
animals had been brought home. On the day of treatment the sow
that had remained iipon the infected farm for five days was sick.
She had a temperature of 104° F. and was very stupid. Serum
was administered in the following doses: Tor the small pigs,
15 cc. ; for the shoats weighing about 150 pounds, 30 cc. ; for the
old sows weighing about 200 pounds, 50 cc.

The sow that was so well advanced with the disease died after
ii few days. jSI^one of the other animals have shown any symptoms
of cholera since the imnumizijig treatment.

Onondaga county. The Origin of this outbreak cannot be
traced, although the troixble started soon after the purchase of
.several rough looking animals and adding them to the herd. The
lierd consisted of 280 hogs when the disease first appeared. The
first deaths were in xVugust Avhen eight died. A number of
Teterinarians were called but they were unable to control the
•disease. The animals continued to die and were still dying up to
November 14, when the remaining animals were treated with
serum. At this time there were eighty of the original herd left.
Two pigs died the night previous to the treatment.

iSerum was administered in the following doses: Four pigs,
two weeks old, received 8 cc. each; eighteen pigs, two to four
weeks old, received 8 to 12 cc. each; twenty pigs, weight about
sixty pounds, received 15 to 18 cc. ; thirteen hogs, weight 200 to
400 pounds, received 40 to 60 cc.

Several of the animals described as weighing 100 pounds did
not appear to be well at the time of the treatment. One of these is
reported to have died later. One of the pigs, weighing about
thirty-five pounds, was reported sick at the time of treatment, but
recovered. Although two animals died the night previous to the
■treatment only one died after the serum was administered.

Oneida county. In this herd twenty animals had died before
the serum was administered. Thirty-five doses were sent to this
J)lace on November 10. In a letter dated December 3, the owner
of the animals reported that the pigs' showing symptoms of cholera
at the time of treatment died. Xone of the others have, as yet,
taken the disease.

TompKns county outhreaJc No. 2. Serum was given as fol-
lows: Five pigs, weight about 35 pounds, 20 cc. ; one shoat,

110

Annual Eepoet of the

weight aboiit 125 pounds, ''■'40 cc. Two animals died shortly after
the treatment. One of them was very sick at the time and the
other exhibited lesions of the chronic type of the disease on post-
mortem.

Table Giving the Eesults of the Treatment witbc, Seeum.

No. of
herd.

No.
treated.

No. of

animals

that died

before

treatment.

Interval
between

first
death and
treatment.

No. of
deaths after
treatment.

RemarljB.

1

IS

1

2 days

1

The animal that died after
treatment was" sick* whenv
treated.

2

80

200

3 months

1

3

100

20

Several weeks

Report not clear. All well anirrnds-at time-
of treatment remained well.

4

6

3

2 to 3 weeks

2

Of the animals:^ that died
after treatment, one was
very sick at time of treat-
ment, the other showed
lesions of chronic type of
the disease.

* This animal was in a very unthrifty condition. The large amount of serum was administered
on this account.

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