NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
RESEARCH WORK ON FOOT-AND-MOUTH DISEASE
215
vaccinia commercially, caused an outbreak in that country. Recently in Norway,
vaccine lymph again was believed to be the source of foot-and-mouth virus which
infected cattle (Magnusson, 1930). The vaccine lymph had been used to vaccinate
cows against cow-pox and the foot-and-mouth virus which it contained had not
been detected earlier because calves on which it had been used were slaughtered
as soon as the lymph had been collected and were not kept with other cattle. It
is noteworthy that although presumably foot-and-mouth virus had been included
in this strain of vaccine lymph for some time it had not caused foot-and-mouth
disease in man. Magnusson also refers to similar occurrences in Switzerland in
1908 and in Hungary in 1917.
The effect of inoculating a mixture of the two viruses was investigated on
guinea-pigs by Mrs. Gibbs in 1929. The occasion was an outbreak of foot-and-
mouth disease near a station used for the manufacture of vaccine lymph in Great
Britain. It was considered therefore, advisable to make sure that the vaccine
did not contain foot-and-mouth virus. No evidence of any such contamination
of the lymph was obtained. The details of the experiments by Dr. Andrews and
Mrs. Gibbs are recorded in Appendices I and II. In further experiments no
difficulty was experienced in separating the two viruses from a mixture made
intentionally in the laboratory.
T.—IMMUNITY.
Four methods have been used with several variations to produce specific
resistance against foot-and-mouth disease.
1. The inoculation of animals with rather large doses of serum from previously
immunised cattle, e.g., doses of about 20 cubic centimetres per live hundred weight
gives a considerable measure of protection for about 10 days. This procedure has
been found to be effective in the case of cattle exposed to infection in the field,
markets, etc.
Serum for this purpose is prepared by Waldmann on the Island of Riems.
This serum is said to be hyperimmune because, in order to produce it, cattle con-
valescent from an attack arc given repeated injections with virus in order to raise
the prophylactic value of their serum. These animals are again given the disease
and further injections with each of the three recognised types of virus in turn so
that the serum may be polyvalent as well as hyperimmune. In France and other
countries the serum from convalescent animals which have simply had an attack
of the disease due to the type of virus prevalent at the time is often used.
2. Inoculation with active virus and at the same time with hyperimmune serum
so as to diminish the severity of the attack whilst not preventing it altogether and
216 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ II, II
in this way allowing the animal to acquire the more lasting kind of resistance which
usually follows an attack of the disease.
The severity of the attack following this kind of inoculation is variable but is
said to be seldom serious. However, the active and lasting immunity which results
is apparently proportional to the amount of illness produced. There is also a stage
of infectivity during the mild attacks. By this means all the cattle rapidly pass
through the disease, but in some cases the eruption of vesicles is unusually late,
being delayed by the serum injected, and the period of quarantine has in Prussia
been extended officially from 14 days to three weeks after the presumed date of
disappearance of infectivity of the local lesions resulting from the combined
inoculation. Twelve days are allowed for the progress and cure of the disease,
making a total quarantine of about five weeks.
Since the cattle inoculated by this combined method are infective for a time
for other animals, all the cattle in their immediate neighbourhood are given a
protective dose of serum in order to prevent them from becoming infected and so
spreading the disease. This method of dealing with outbreaks is called the
" Ringimfung " in Germany and is considered, especially in Prussia, to give very
valuable results, but for various reasons the spread of disease and the renewed
occurrence of outbreaks is not always prevented.
3. Several methods of inoculation with attenuated virus have been used at
different times. For this purpose strains of virus have been selected which have
been adapted to another species of animal with resulting diminution of " virulence "
for cattle, in imitation of the attenuation for man of small-pox virus after adapta-
tion to bovines. Strains of virus have also been chosen which were causing a mild
epizootic in cattle. No method of obtaining a certainly attenuated virus which can
be depended on not to produce severe disease has yet been discovered.
4. The inoculation of animals with foot-and-mouth virus which has been killed
by treatment with formalin was tried by Vallée and Rinjard (1926). Bedson and
Maitland (1927) independently experimented with formalised virus on guinea-pigs.
A considerable degree of resistance is regularly produced, but it is necessary to use
a virus of high potency and to inject vaccine equivalent to 5,000 or 10,000
minimal infective doses of virus. It is essential that the formalin should not be
too strong and the temperature at which the virus is treated should not be too high
nor maintained too long otherwise the vaccine becomes inert.
When prepared the vaccine will keep for some weeks in the cold room. The
protection of guinea-pigs is not complete against a strong dose of virus, but very
large doses of virus given intramuscularly are completely resisted for a period of
many months. If the virus is inoculated intradermally into a vaccinated guinea-
RESEARCH WORK ON FOOT-AND-MOUTH DISEASE
217
pig local vesicles form but generalisation does not occur if the test is made 2 or 3
weeks later.
Experiments by Mrs. Gibbs show that probably the immunity produced by
formalised vaccine is of the same kind as that following an attack of the disease,
but is of lower grade.
Many successful experiments with dead vaccine have been carried out in this
country, chiefly on guinea-pigs, but Vallée has demonstrated its efficiency for cattle
in a few experiments.
The chief objections to the use of vaccine in practice for the immunisation of
cattle are two. First the difficulty in obtaining sufficient virus to make a supply of
vaccine, and, secondly, the paucity of detailed accounts of properly controlled
experiments with cattle on a large scale.
It is important that for this purpose the vaccine should be prepared by an
exact method, and that it should be thoroughly tested both for loss of infectivity
and for its immunising power in guinea-pigs before it is used on cattle.
To remedy the first defect Vallée suggested using the whole bodies of guinea-
pigs deprived of skin, bones and viscera, ground up and formalised. Laboratory
experiments by Dr. M. C. Maitland (1928) showed that virus when ground up with
muscle may be rapidly destroyed by the acid produced from the muscle and Mr.
Galloway has shown that the amount of virus derived from an infected guinea-pig's
feet and mouth with the addition of the blood is not materially increased by adding
the rest of the carcase as was done by Vallée.
It has been shown that the concentration of virus in the blood serum is about
one-thousandth of that in the vesicle fluid. The amount of virus in the blood of
infected cattle is very variable ; nevertheless the blood or blood serum appears at
present to be the best available source of virus for making vaccine on a large scale.
It is possible, however, that vesicle fluid and epithelium might be collected in suffi-
cient quantity. Donatien, Leslequard and Pauturieux (1930) claim to have had
success in using Vallée's vaccine on 4 calves.
Vallée (1930) mentions the use of over 6,000 doses of prophylactic vaccine
made in various ways in France and records experiments in the field on several
controlled groups of cattle in which a vaccine appeared to protect the animals
against an attack of the disease.
Skomorokoff (1930) has reported encouraging results from the use of formalised
vaccine in 27 cattle tested by inoculation and 24 by exposure to infection from
diseased animals ; the exact method by which the vaccine was prepared was not
reported. Helm (1930) tested vaccine made by Vallée's method from guinea-pig
218 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ II, II
carcases, but obtained no encouraging results in a large series of guinea-pigs.
Waldmann (Inter. Kongr. 1930, p. 17) also tested vaccine prepared in the same
way, but obtained no evidence of protection. He also tested on cattle a vaccine
prepared from bovine infected epithelium without success. Waldmann stated that
he and Trautwein had tried many methods of inactivating virus to serve as vaccine
but, though no practical results had yet been obtained, he felt more hopeful than
in former years that a satisfactory vaccine might be discovered.
Details of experiments with formalised vaccine on guinea-pigs are reported in
Appendix II.
5. The nature of immunity.—" Tissue " and " humoral " immunity. The study
of immunity in this country, while confirming the existence of different degrees of
immunity according to whether the test inoculation is intradermal, intramuscular or
intravenous suggests that these are merely due to a different susceptibility of the
site of inoculation, whether the animals tested are quite susceptible or more or less
immune.
A much larger dose of virus is required to infect a susceptible animal when
given intramuscularly, about 100 times that needed by intradermal inoculation ; a
similar but greater difference is found when an immune animal is inoculated.
The difference between susceptible and immuned animals appears to be related
to the amount of antibodies present in the body.
The result of inoculating virus into immune rabits which have recovered from
an attack has been investigated by Mr. Galloway by trying to recover a recently
administered dose of virus from the site of inoculation and from the blood at
different intervals of time.
The virus was sought 30 minutes to 36 hours after the dose had been given and
was found to have been very rapidly destroyed or neutralised. Mrs. Gibbs had
found a similar extremely rapid disappearance of virus from the blood of vaccinated
guinea-pigs which had been inoculated with potent virus into the blood vessels. In
both instances the virus is speedily neutralised whether the immunity is due to the
disease or to vaccination.
Immunity in cattle.—The duration of immunity to foot-and-mouth disease in
cattle has been very variously estimated. Formerly it was supposed to last a very
short time. This low estimate of resistance to a second attack is now known to
have been due in many cases to a fresh epizootic due to a second type of virus
having infected animals which were still quite immune to the type with which they
were orginally infected.
Dr. Andrews has tested 22 cattle which have remained under observation at
Pirbright after an attack of the disease. Eighteen cattle which had been infected
which 0 virus were tested by intramuscular (I. M.) inoculation with the same type
RESEARCH WORK ON FOOT-AND-MOUTH DISEASE
219
of virus and no evidence was obtained of a decline of immunity after a period vary-
ing from 13 to 32 months had elapsed since the first attack (so called humoral
immunity). Four cattle were tested (I. D.), intradermally (the test for so-called
" tissue " immunity) after 15 to 20 months. One of these had a vesicle on one
foot and another was lame without other signs of disease. These last two animals
illustrate the greater severity of a test for immunity by I. D. inoculation.
W.—THE ORIGIN OF FRESH OUTBREAKS OF FOOT-AND-MOUTH DISEASE.
Outbreaks among farm animals sometimes occur of unknown or only suspected
origins.
Exact and carefully controlled observation of the disease has multiplied new
sources from which it is possible that infection may arise. The research of the last
8 or 10 years has indicated certain sources of infection which call especially for
further observation and experiment.
These may be placed in three categories.
1. Foci of virus outside the animal body. The conditions needed for survival
of the virus have been discussed in former years and on pages 34 ff. of this report.
The remarkable power of survival in certain articles of fodder such as contaminated
hay and bran, on hides or the leather or rubber of boots, has been recorded.
2. Experience has shown a large range of animal species which can be infected
with foot-and-mouth disease in a form resembling that found in farm animals. The
transference of infection from one species to another does not always take place
easily and adaptation of the virus to the new species has sometimes to be acquired
gradually before a well-marked infection occurs with regularity. Natural transmis-
sion between small animals living together in cages does not occur as a rule except
in the case of hedgehogs and, less frequently, in rats.
Whether the susceptibility of indigenous animals is of much practical import-
ance cannot yet be stated.
The discovery of very inconspicuous signs of the disease in rats must increase
the care with which symptoms of infection in these animals are sought, and adds
fresh importance to the warfare waged against these animals. The nocturnal and
therefore, often unobserved habits of the hedgehog and its undoubted high suscepti-
bility make further enquiries concerning this animal important.
3. It has been shown that carcases of animals which have been killed during
the infective period may contain deposits of active virus for long periods after being
subjected to various pickling processes and especially when the carcase has been
kept at low temperatures. One well established method by which pigs can become
infected from such carcases is by feeding them with uncooked crushed bones.
220 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ II, II
Meat scraps kept at low temperature are also infective. This was found to be
the source of the outbreak among pigs in California, reported by Mohler (1929).
In this case the pigs first received the meat scraps 57 days after the carcases had
been shipped in S. America.
It is clear then that importation of infected meat or offals in a chilled or
frozen state is a ready means by which infective material can be conveyed to this
country and that one way in which the infection may then be transmitted to farm
animals is by the feeding of pigs with parts of the carcase, especially with the bones.
Whether this undesirable event occurs or not depends on the state of the
animals at the time and place where they are slaughtered and on how the carcases
are disposed of after arrival in this country. The dissemination of active virus by
carcases of infected animals might occur from one part of the country to another as
well as by importation from abroad if cases of disease were overlooked.
BIHAR AND ORISSA VETERINARY COLLEGE, PATNA.
NOTICE.
A post-graduate class will be opened at the Bihar and Orissa Veterinary College
from 1st July 1932, for the advanced training of Veterinary graduates in
(1) Pathology and Bacteriology, including Meat and Milk Inspection and Post-
mortem technique, (2) Histology, (3) Veterinary Hygiene, Dietetics and Genetics
and (4) Veterinary Medicine including parasitic, contagious and inanition diseases.
The course will be held for six months only for which a sum of Rs. 60 will be
charged as tuition fee and Rs. 10 as admission fee. Seat rent for the hostel will be
at the rate of Rs. 5 per month.
Private candidates desiring admission should apply to the Principal, Bihar and
Orissa Veterinary College, on or before the 15th June 1932, with the original
diploma and a certificate of character.
Further particulars, if required, may be obtained on application from the
Principal.
PATNA ;
The 4th May 1932.
R. T. DAVIS, I.V.S.,
Principal,
Bihar and Orissa Veterinary College.
ORIGINAL ARTICLES
SULPHUR AND SULPHATE BALANCE EXPERIMENTS
WITH CATTLE
BY
F. J. WARTH, M.Sc.,
Physiological Chemist, Animal Nutrition Section, Imperial Department of Agriculture,
Bangalore.
(Received for publication on 11th April 1932.)
While cystine must remain the main factor in sulphur metabolism, we may ask
the question : Is the body capable of assimilating any other form of sulphur com-
pound than cystine ?
The widespread occurrence of sulphatase in the animal body [Neuberg and
Simon, 1925 ; Rosenfeld, 1925] signifies some mechanism for the utilization of
sulphate ; hence it is reasonable to enquire whether inorganic sulphate can be
assimilated. The question has been studied recently by Dennis and Leeke [1925].
These authors, having devised an effective method for determining the total sulphate
in tissues, made intravenous injections of hypertonic Na 2 SO 4 in dogs. On examining
the tissues of these animals, they found no appreciable accumulation of sulphate in
any organ and concluded that there is no evidence to show assimilation. Concern-
ing the intestinal absorption of sulphate, the work of Hertz, Cook and Schlessinger
[1908] on the cathartic effect of large doses of sulphate must be noted. These
workers showed clearly that the ingested sulphate is taken up very efficiently into
the blood stream, the liquid stools containing no more than the normal amount of
sulphate and the cathartic effect being due to sulphate peripheral to the intestine.
They found, however, that the faecal sulphate increased at a later stage, showing
that part of the excess in the blood is re-excreted through this channel.
The present author's experiments described in the sequel lead to the following
conclusions :—
1. With certain types of ration there is invariably some loss of inorganic
sulphate. The amount excreted in the urine is always less than the amount
ingested. The quantity in the sweat is negligible and the quantity in the faeces is
small and does not account for the sulphate lost.
2. The possibility has to be considered that the sulphate was in the faeces and
has been altered by bacterial activity. In this case it might be convrtede eithrə
into sulphide or into organic sulphur.
( 225 )
B
226 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [II, III
The faeces were found to contain traces of sulphide which were negligible.
Further, it has been found that the sulphide content of the faeces is related to the
nature of the fodder and not to the amount of sulphate lost. To study the possi-
bility of conversion to organic sulphur, faeces with added sulphate were incubated.
This did not lead to measurable loss of sulphate in 8 days. The evidence from
these tests, although the figures show complete recovery of added sulphate, is not
conclusive in itself, but it is corroborative.
3. Balance experiments have been carried out to determine the fate of the
sulphur in the ration. It is shown clearly that, while the total sulphur is accounted
for satisfactorily, there is a loss of inorganic sulphate and a corresponding gain of
organic sulphur. The inorganic sulphate lost is, therefore, not lost from the body
as H 2 S, but is represented by organic sulphur in the faeces.
4. There is evidence to show that when small amounts are fed, the organic
sulphur of groundnut cake does not appear, to an appreciable extent, in the urine,
but is excreted in the faeces. This observation, on which emphasis is laid, seems to
be related to work originated by Abderhalden's researches [1905] in which it was
shown that cystine assimilated as a dipeptide in conjunction with another amino
acid suffers less oxidation than ingested free cystine. In contrast to the above
results, it has been found that when the quantity of groundnut cake is considerably
increased, the additional organic sulphur, thus introduced, is excreted almost
quantitatively as sulphate in the urine. These results indicate that such digestible
organic sulphur may be excreted through two channels, the urinary excretion as
sulphate apparently representing the fate of a luxury supply.
5. Perhaps it is a significant fact that the lost sulphate (believed to be meta-
bolised) and the organic sulphur of groundnut cake (when fed in small amounts and
certainly digestible) are both excreted by the same channel, namely, in the faeces.
It should be explained that this work originated from an examination, by the
author, of cattle urines representing various typical fodders. Only 3 samples out
of 20 contained free sulphate, thus indicating a general shortage of sulphur.
For brevity, methods will not be described, except one, namely the method for
determining sulphate in food-stuffs. The last is an important figure for calculating
sulphate balances. Tests showed that simple extraction with dilute HCl is quite
as effective for this purpose as the process described by Aitken [1930]. The extrac-
tion method finally adopted was as follows :—
10 grms. fodder are weighed into a dry flask, 50 c.c. 2 per cent. HCl are
measured in and allowed to soak. The wet semifluid is thoroughly shaken, washed
down with 50 c.c. acid, evacuated under the pump to remove air and allowed to
stand overnight. The liquid is filtered through a dry filter, an aliquot is concen-
SULPHUR AND SULPHATE BALANCE EXPERIMENTS WITH CATTLE
227
trated, the humin filtered off and sulphate precipitated. Average results with food-
stuffs used in these experiments are as follows :—
Dhub grass . . . . . . . . . . .
Ragi straw . . . . . . . . . . .
Mature hay . . . . . . . . . . .
Cabbage leaf . . . . . . . . . . .
Carrot root . . . . . . . . . . .
Carrot top . . . . . . . . . . .
Groundnut cake . . . . . . . . . . .
Wheat bran . . . . . . . . . . .
Inorganic sulphate
as grms. S.
per 100 parts
dry matter.
.330
.117
.055
.579
.130
.289
0.0
0.0
Experimental Results.
1. Preliminary observations on sulphate feeding. Two bullocks receiving ragi
straw (Eleusine coracana) and two receiving mature hay were used. Sulphate was
fed at the rate of 40 c.c., 10 per cent. Na 2 SO 4 . With the ragi straw ration most of
the added sulphate was recovered at once in the urine. With the hay ration there
was retention.
The feeding of sulphate to the animals on the hay ration was continued for one
month, the quantity being doubled at the end of half the period. The results are
summarised in the accompanying table :—
TABLE I.
Sulphate excretion by bullocks.
(Sulphate in grms. sulphur per day).
Date
November . .
December . .
December . .
1-21
. . 30
1-2
. . 9-12
18-20
. . 30-31
Supplement
0.0
...
0.9
...
1.8
...
Excretion
Bullock 1
1.838
1.649
1.728
2.044
2.140
2.332
Bullock 2
1.407
1.376
1.468
1.852
2.058
2.469
B 2
228 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [II, III
In carrying out this trial, it was expected that, at some stage, the sulphate
deficiency would be satisfied and, that, thereafter, the added sulphate would be
completely excreted. It is evident that this did not occur. To elucidate this
peculiar effect, it was decided to carry out sulphate and total sulphur balance
experiments with the two fodders, ragi straw and mature hay.
EXPERIMENTS WITH RAGI STRAW.
(a) Excretion of volatile phenol and sulphates.
The ragi straw ration was fed to two bullocks, G and H without a sulphate
supplement. The following are typical results with this ration :—
TABLE II.
Excretion of sulphates and phenols with ragi straw ration.
Daily sulphate and phenol excretion expressed as grms. S.
—
G. . . . . . . .
H. . . . . . . .
Total
SO 4
3.969
4.036
Free
SO 4
2.221
2.356
Ethereal
SO 4
1.750
1.696
Volatile
Phenols
1.521
1.648
These figures (averages from three consecutive days determinations) indicate
that in this urine the ethereal sulphate is very largely accounted for by the volatile
phenol.
The characteristics of ragi straw urine may be summarised thus :—
1. High total sulphate.
2. High free sulphate, i.e., there is excess of sulphate.
3. Moderate amount of volatile phenol which accounts for most of the
ethereal sulphate.
(b) Sulphate balance experiments.
Determinations covering 21 weeks have shown that the sulphate lost in the
sweat is negligible. The amount voided in the faeces (from 0.14 to 0.27 grms.
sulphur daily) is appreciable but not significant here. The sulphate balance can