Synonyms. Definition. Susceptible animals: cloven footed, all warm
blooded animals. Historic notes; Geographical distribution; English
invasions in 18th and 19th centuries; North and South American
invasions in 1870; In Asia from immemorial times. Causes: infection in
liquid of vesicles, saliva on pastures, roads, feeding and drinking
places, halters, etc.; from feet on pastures, buildings, yards, roads,
cars, boats, etc.; from teats through milk. Microbe not certainly
known, micrococci, streptococci and bacilli found. Virus inert when
dried 24 hours at 88° F.; survived 9 months at 32° F., attack
immunizes for 5 months; injection of 1 lymph and 2 of blood of immune
renders refractory; filtered lymph still virulent; microbe probably
infinitesimal; accessory causes: movement, mingling of cattle, sheep,
swine, etc., war, trade, common pasturage, infected roads, ships,
yards, halters, etc. Symptoms: incubation 36 hours to 6 days; slight
fever; redness, tenderness of buccal mucosa and teats, grinding teeth,
smacking tongue, tender feet, shaking them backward, bullæ on mouth
and teats, not nodular, nor chambered as in variola, salivation,
bloody, circular or irregular raw sores, vesicles and erosions in
interdigital space, shedding hoofs, sheep walk on knees, gangrenous
mammitis; intestinal eruption and diarrhœa in sucklings. Mortality.
Prognosis; recovery in 15 days, deaths rare if cared for. Losses from
destruction of product and emaciation—occasional abortion. Diagnosis:
based on infection of all exposed bisulcates, localization on mouth,
teats and feet, inoculability on other warm blooded animals,
unchambered vesicles, slight fever, and prompt recovery. Notes of
affection in man. Symptoms in man. Prevention and treatment in man.
Prevention in animals: exclusion of contagion, immediate and mediate;
close infected pastures and roads, stop all movement of bisulcates,
disinfect all boats, cars, places and things exposed, exclude
visitors, guarantees with strange animals, quarantine and disinfect
arrivals, exclude fresh animal products, fodder and litter, wash,
disinfect soiled clothes. Inoculation undesirable. Treatment in
animals: cleanliness, dryness, disinfection, segregate sick and well,
gaseous antiseptics, liquid ointments. Gruels, mashes, sliced, boiled,
or pulped roots. Local dressings for mouth, teats and feet. Evulsion
of hoof. Mammitis.
_Synonyms._ Aphthous fever: Aphtha Epizoötica, Eczema Epizoötica.
_Definition._ An acute infectious disease of the lower animals but
especially of ruminants, characterized by a slight fever and the
eruption of vesicles, or ballæ on the skin and mucosæ, and usually those
of the mouth, feet and teats.
_Susceptible Animals._ The animals that prove the most obnoxious to the
disease are the bisulcates—large and small ruminants and swine. Man
however is susceptible as are also horses, dogs, cats and fowls, when
they are inoculated or fed upon the infected milk or other products. It
is doubtful if any warm-blooded animal enjoys an immunity.
_History, Geographical Distribution._ Toward the middle of the
eighteenth century this disease prevailed in Central Europe and England.
The latter country stamped out both this and the Rinderpest, but it
continued to prevail on the Continent and was re-imported into England
in 1839. It reached America through an importation from England to
Montreal in 1870, but owing to more or less effective quarantine, to the
absence of cattle traffic from east to west, and above all to the
prolonged confinement in yards and stables during our northern winter,
it burnt itself out in the course of the year. In Asia it has prevailed
from time immemorial, and it was imported into South America in 1870.
_Etiology._ This disease has long been known as caused by infection
alone. Excluded from England in the middle of the eighteenth century it
did not appear again until re-imported in the middle of the nineteenth,
and then speedily overran the whole island except the breeding districts
into which strange stock were never taken. In South America it was
unknown until imported from the Old World into the Argentine Republic
and then it made a wide extension and maintained itself where the stock
was kept on unfenced ranches. In our fenced Northeastern states it died
out and has not reappeared.
The infection is especially resident in the vesicles or aphthæ. From the
mouth this is distributed, with the abundant drivelling saliva, on
pastures, roads, feeding and drinking troughs, ponds, streams and
halters, and readily communicates the disease to healthy stock following
in the same places. From the feet and especially the interdigital space,
it is left on the vegetation, buildings, yards, cars, boats and all
other possible media to infect other stock in turn. From the teats it
mingles with the milk so as to infect the young suckling and all animals
and men to whom the milk may be given. It may become dried on litter and
other light objects and carried by the winds, or it may be carried on
the feet of men or animals including birds, but apart from this it is
not readily diffused and oftentimes a broad highway may set a limit to
its propagation.
The infecting microbe is not definitely known. Nosotti found a
micrococcus in the lymph of the vesicle, which stained readily in
aniline colors, was easily cultivated and pathogenic. Klein found a
streptococcus which, similarly tested, presented an equal claim to be
the causative factor. Bassianus and Siegel found in the blood and
tissues of a person who died of foot and mouth disease a small oval
bacillus, which they later obtained from the vesicles of three children
who were suffering from the disease, and from animals attacked in two
successive epizoötics. With this they first successfully inoculated a
calf and from the pure cultures obtained from its blood, inoculated
three calves and a young pig.
Löffler and Frosch, the recent commission on foot and mouth disease in
Germany, report that no organisms could be seen nor cultivated from the
lymph found in recent bullæ of the buccal mucosa, though this lymph
proved virulent when inoculated on calves.
They found that the lymph became inert when dried for 24 hours at 31° C.
(88° F.), while it retained its vitality and virulence after exposure
for 9 months to a temperature of 0° C. They concluded that it could not
penetrate through the unbroken skin nor mucosa, and that it was most
effective when injected into the blood or peritoneal cavity. One attack
conferred immunity for 5 months. Blood from immune animals, injected
into susceptible ones, does not confer immunity, but 75 per cent. could
be rendered immune if injected with a mixture of the lymph from the
vesicle and double the same amount of the blood from the immune animal.
Animals so treated become immune to 100 times the infecting dose.
Filtered lymph was still virulent and the commission suggests that the
microbe may be so small as to pass through the filter, and escape
discovery by the most powerful lenses. An object one fifth the size of
the smallest known bacillus—that of influenza—would be invisible under
our best microscope.
By actual experiment the virus has been found in the nose, larynx,
bronchia, stomach and intestines, but into all these the virulent lymph
of the bullæ can find its way. In the intestines, indeed, in cases
caused by feeding, bullæ have been found on the mucosa.
A most important question would be that of the virulence of the milk,
but inasmuch as the vesicles appear on the teats and even on the
openings of the milk ducts, and in bursting discharge their contents
with the milk into the pail, the milk becomes per force infecting. The
experiment of Hertwig and his students who infected themselves by
drinking the warm milk by way of experiment, has been often repeated
unwittingly by unwilling victims, and the many cases of calves, pigs and
chickens contracting the disease by consuming the otherwise discarded
milk leaves no room for doubt that this product is often infecting.
Among conditions contributing to a spread of infection, nothing is more
potent than a free movement of ruminants, and swine whether determined
by war, trade, or the intermingling of different herds on commons or
unfenced ranges. In infected countries, in which cattle are distributed
through large central markets there is always a wide extension after one
of these fairs, the infection being narrowly circumscribed to herds
receiving cattle from the fair, or those that have travelled on the same
roads or fields after the market cattle. It has repeatedly happened that
cattle shipped from the United States, where this disease has long been
unknown, have been found diseased on their arrival at a British port,
simply because they have been tied upon the passage with halters
formerly used on infected Irish or Continental stock.
_Symptoms in animals._ There is first a period of incubation shorter in
hot than in cold weather and varying from 36 hours to 6 days
(exceptionally 15 days). It is altogether probable that prolonged
incubation is really delayed infection, the virus having been attached
to the feet for some time before it entered the tissues. Cattle usually
show the disease two days after exposure in a public market, building or
conveyance.
There is first moderate hyperthermia (102° to 103° F.), indicated by the
clinical thermometer before there is any outward sign of ill health.
There may be erection of the hair, tremors or distinct shivering,
dryness and heat of the muzzle, redness and even tenderness of the
buccal mucosa and teats, saliva drivels from the mouth or may show as a
frothy mass at the commissures or margins of the lips, and there may be
grinding of the teeth and a peculiar smacking of the tongue and hard
palate which may be heard at a considerable distance. There are greatly
impaired appetite and rumination. Tenderness of the feet is shown by
halting or lameness and by the extension backward and shaking of the
hind feet in turn.
With the appearance of the eruption, usually on the second day of
illness, the fever as a rule moderates, and on examination of the mouth
bullæ of ⅓d. to 1 inch in diameter may be found on the inside of the
lips, and cheeks, or on the palate and tongue, with, in many cases, a
congested areola, but showing no nodule as in variola. These bullæ may
extend to the muzzle, pituitary membrane or pharynx. They burst very
soon after their formation, exposing a red base of inflamed corium, with
a clearly rounded margin, or, at first, with shreds of the torn
epithelial covering. The salivation now becomes more profuse, glairy and
even bloody, and there is more active movement of the tongue. When the
bullæ have been confluent there are formed extensive red patches denuded
of epithelium, and the suffering causes a complete but temporary
dysphagia. The renewal of the epithelium, however, takes place promptly
and may be well advanced in four or five days. Upon the teats the bullæ
appear at about the same time but are usually smaller than the buccal,
and do not show the thickened base of cow pox. They burst in 36 to 48
hours unless broken earlier by the hands of the milker, forming sores
comparable to those of the mouth, which are liable to be kept up by the
necessary manipulations in milking.
Upon the feet the eruption shows especially in the interdigital space,
at first as vesicles smaller than those of the mouth and teats, leaving
erosions and ulcers which extend under the adjacent horn, and upward on
the front and back of the pastern. From exposure to mud and filth these
are liable to be kept up even longer than those of the mouth and teats,
and under neglect the entire hoof is often shed. In sheep and swine the
disease may be localized almost exclusively in the feet. Sheep will even
walk on the knees.
In young animals and those fed on the milk, the eruption may take place
on the intestinal mucosa with violent congestion, diarrhœa and a fatal
issue. Aggravated cases may show gangrenous mammitis or abortions.
_Mortality and Prognosis._ While there are seasons of special pathogenic
severity, yet as a rule, the foot and mouth disease is a mild affection
and unless neglected, the patients entirely recover in about fifteen
days. The pecuniary loss in dairy and feeding cattle has been found to
average in Great Britain about $10 per head, and as few animals escape,
the consequences are usually very serious. In England the losses from
this disease in 1883 reached $5,000,000, in France, those of 1871 were
$7,500,000 and in Switzerland, $2,500,000. In Germany, over 7,000,000
animals suffered from 1889–94.
_Differential Diagnosis._ While a mistake might be made in an isolated
case, such a thing should be absolutely impossible where cattle and
other animals are collected in herds. The rapid infection of the whole
herd, the implication of sheep and swine along with the cattle, and the
eruption of the characteristic bullæ on the mouth, feet and udder or on
two of these locations to the exclusion of the rest of the body, is not
likely to be counterfeited by another disease. An outbreak of gangrenous
ergotism in Kansas, Missouri and Illinois in the spring of 1884, was
pronounced to be foot and mouth disease by a number of veterinarians,
including an expert sent by the Government of Canada. On behalf of the
U. S. Treasury I investigated the disease, which caused in many cases
sores on the mouths and feet, but it spared all sheep and swine, could
not be conveyed to them nor to new born calves by inoculation, and in
many cases it caused gangrene of all the tissues, soft and hard, and
separation of the limb at a given point, often near the tarsus. The
quarantines were raised, the disease made no further extension, and the
existing panic subsided.
_Infection of Man._ The first authentic record of this affection in man
we owe to Valentin, who records that during the outbreak in Hesse in
1695 men suffered from inflammation of the gums, tongue and mouth.
Michel Sagar says, that in 1764 men who drank the milk were affected
with aphtha. In 1828 it was conveyed from animals to men in Bohemia
(Nadberny), in Styria (Levitsky) and Wurtemberg (Kolb). In 1834, three
veterinarians, Hertwig, Mann and Villain, voluntarily drank a quart each
of the warm milk of a cow suffering from this affection. On the second
day Hertwig suffered from fever, headache and itching of the hands and
fingers. Five days later bullæ formed on the hands and fingers, the
tongue, cheeks and lips. In the two others the eruption was confined to
the buccal mucosa. Since that time records of the infection of human
beings have been very numerous. During the American epizoötic of 1870 I
met with the case of a farmer at South Dover, N. Y., who suffered from
sore mouth and blisters along the margin of the tongue from drinking the
milk. The danger is greatest in children on an exclusive milk diet and
who drink it warm. Kolb in 1828, noticed acid vomiting and diarrhœa in
such subjects, Hübner observed that beside the buccal eruption such
children often suffered from inflammation of the stomach and bowels and
that very young children fed on the milk of the diseased cows died.
Balfour, Watson and others have noticed similar results in Scotland.
Allbutt saw the buccal eruption in three children in Yorkshire, England,
during the local prevalence of the English epizoötic in 1883, and
secured information of a number of other cases in the same district.
A number of cases were recorded during 1893 in Germany. A shepherd
infected himself by holding in his mouth the knife with which he had
pared the diseased feet of sheep, and another workman and a veterinarian
had extensive eruptions on the hands after dressing the affected feet. A
number of milk-maids were infected by milking, the eruption appearing on
the hands, and in one case on the breast. A child fed on the milk of
diseased cows, had chill and fever with gastric disturbance, and later
an eruption of vesicles on the lips and tongue and between the fingers
and toes.
Again, in 1895, during the prevalence of foot and mouth disease in the
southern part of Berlin, a considerable number of the milk consumers
suffered from fever with the eruption of bullæ on the tongue and buccal
mucosa generally, which on early bursting left very painful ulcerations.
The acute disease did not last more than five days, but left a sense of
great weakness for a time. Virchow, who made an investigation,
unhesitatingly pronounced it to be foot and mouth disease.
Cases of infection through butter made from infected milk are on record.
A Berlin veterinary student suffered from the buccal eruption and
erysipelatoid swelling of the ear, and a German clergyman had in
addition a period of chilliness, fever, diarrhœa and pruritus. Similarly
Schneider quotes cases determined by infected cheese, and Friedberger
and Fröhner, cases caused by virulent buttermilk.
_Symptoms in Man._ In man there is observed the tendency to localization
on the same points as in animals. As the hands are naturally exposed to
infection by milking or treating the diseased animals, they are
especially obnoxious to the eruption, and the same is true of the mouth
when the infected milk or other dairy products are consumed. The bullæ
on the buccal mucosa are generally confluent, and often extend to the
fauces and pharynx, rendering speech difficult and swallowing painful,
and leaving extensive and painful sores which, however, soon heal up. In
women the bullæ have been seen around the congested nipples, and in
exceptional cases they have been generally diffused over the body.
In cases due to drinking the milk, the early febrile symptoms are liable
to be accompanied or followed by nausea, anorexia, abdominal pain and
diarrhœa, and still later by the cutaneous and buccal eruption.
The duration of the disease is from 10 to 15 days and as a rule no
permanent scars are left on the skin or mucous membranes.
The _diagnosis_ is assisted by the knowledge of the prevalence of the
disease in herds in the district, and that the patient has handled the
diseased animals, or drunk their milk, or eaten their butter or cheese
products. The predilection of the eruption for the fingers, the roots of
the nails and the mouth is very significant. The disease follows an
acute course and convalescence is complete in ten or fifteen days, which
serves to differentiate it from most skin eruptions. From variola which
pursues an equally rapid course it is distinguished by the absence of
the primary nodular swelling, and of the septa or pillars that divide
the mature pock into independent chambers.
_Prophylactics._ The best prevention for man is to exclude the disease
from the country and its herds as is now the case in the United States.
When the disease does exist in herds the attendants should cauterize any
sores on the hands, and wash the hands with an antiseptic, such as a 10
per cent. carbolic acid solution, after handling the diseased. The milk
and its manufactured products—butter and cheese—should be withheld from
consumption until after the herd has recovered. Infection can be
obviated by boiling the milk.
_Treatment._ The disease follows a rapid course and is self-limiting,
and usually benign so that active treatment is not urgently demanded.
The local lesions are best met by non-poisonous antiseptics, such as:
borax in powder or strong solution; boric acid (4:100); sodium
hyposulphite (½ oz. 1 qt.); chlorate of potash (½ oz. to 1 quart);
salicylic acid (1:100); or salicylate of soda. Pounded ice may be used
as a soothing agent. The cutaneous lesions may be wrapped in cloth wet
with one or other of the antiseptic lotions. Any disposition to ulcerate
may be met by the stick of silver nitrate.
Slightly laxative or diuretic agents may be employed for their febrifuge
and eliminating properties and the food should be light, easily
digestible and given cold.
_Prevention in Animals._ When the disease exists in a country or
district this includes all measures preventive of immediate or mediate
contagion. Arrest of all movement of cloven footed animals in infected
districts, disinfection of cars, boats and other conveyances, of
markets, yards, highways, seclusion of infected herds and pastures,
exclusion of visitors, disinfection of products, certificates of
soundness of origin, thorough disinfection after recovery of the herd,
such are the leading points to attend to. Inspection or closure of fairs
and markets is desirable and any exposure of diseased or infected
animals should be visited with heavy penalty, in addition to the cost of
detention and supervision. For a noninfected country a certificate and
guarantee of non-exposure with each cloven-footed animal imported, and
of thorough disinfection of the cars, boats, halters or other objects
used upon them, and of the places, fodder and litter supplied, together
with a quarantine (1 week) and surface disinfection should be required
under penalty. Exclusion of fresh hides, bones, guts, hair, bristles,
wool, horn, as well as of fodder and litter is essential. Cattle
attendants, drivers and others whose clothes are soiled with the
products of the barn, should have the same washed and disinfected.
Inoculation has been proposed, and even practiced to pass a whole herd
promptly through the malady, but as immunity lasts but three months, and
the attendant risks to other herds are greatly encreased it is at once
an economic blunder, and a great injury to adjoining owners. Any
resulting extension to other herds should be an occasion for a verdict
for damages at common law.
_Treatment in Animals._ Provision is first made against extension of the
infection. The floor should be kept clean, dry and covered with sawdust,
tan bark, gypsum or litter sprinkled with these or with phenic acid. The
herd should be divided into two lots—the apparently sound, and unsound
kept strictly apart under separate attendants, above all separate
milkers. As soon as any symptoms are shown by an animal in the sound
enclosure it must be instantly transferred to the other and its stall
disinfected. Antiseptics such as gaseous iodine (two tablespoonful of
tincture of iodine, thrown into a quart of boiling water twice daily),
sulphurous acid, salicylic acid, creolin, lysol or other ointment on the
feet and teats, may also be used. In this way it may be possible to save
a number from an attack, yet most commonly the exposure is common and
universal and the malady develops in all simultaneously. For those
already attacked, gruels, mashes, and cool pulped, finely sliced or
boiled roots may be all that is required, the disease runs its course
and recovery ensues in 15 days. As local dressings the following may
serve as examples: for the mouth, borax, chlorate of potash, salicylate
or sulphite of soda 2 drs. to 1 quart water; phenic acid, creolin, or
lysol, one or two teaspoonfuls to a quart; for the foot, clean the
interdigital space and apply tar and carbolic acid with bandage, or use
solutions of creolin, lysol, pyoktanin or blue-stone; in aggravated
cases strong mineral acids with tar; for the teats, ointments of boric
or salicylic acid, creolin, lysol, naphthalin or napthol. Separation of
the hoof or mammitis will require treatment according to indications.