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HYDROPHOBIA

Categories: Infectious Diseases

Rabies and hydrophobia are two different terms, meaning the
same disease, the former meaning to rage or become mad. This term applies

more especially to the disease as it exists in the maniacal form in the

lower animals, while hydrophobia comes from the Greek, meaning "dread of

water." As we occasionally find this dread of water only in the human

subject, the term is properly used in such a case. The lower animals

frequently
ttempt to drink water even though the act brings on a

spasmodic contraction of the swallowing (deglutitory) muscles. Hydrophobia

is an acute infectious disease communicated to man by the bite of an

animal suffering from rabies. It is due to a definite specific virus which

is transmitted through the saliva by the bite of a rabid animal. Its

natural habitat (location) is the nervous system, and it does not retain

its virulence when introduced into any other system of organs. It is

essentially a nervous disease and transmitted by the saliva of rabid

animals. When inoculated into a wound this virus must come in contact with

a broken nerve trunk in order to survive and reproduce itself. If by

accident it attacks the end of the broken nerve trunk, it slowly and

gradually extends to the higher nerve centers and eventually produces the

disease.







The incubation, or the time it takes for the disease to develop, varies,

but usually is from three to six months. There is a recorded case where

the person began to show symptoms of the disease thirteen days after

having received a severe wound on the head. The incubation period is

seldom longer than six months. The symptoms of the disease in the human

being vary within narrow limits. There are three classic symptoms usually

encountered, and these are fear, apprehension or excitement, together with

deglutitory (swallowing) spasms, terminating in general paralysis. The

patient remains conscious of his agony to the end, but the period of

illness is of short duration, lasting from one to three days.



The bites of rabid dogs cause ninety per cent of the cases in man and

animals. The cat is the next important factor in spreading the disease and

about six per cent of the cases are caused by this animal. For other cases

four per cent come from bites of horses, wolves, foxes, etc. The wolf in

Russia, or other animals like it, may be the chief cause there; but dogs

cause ninety per cent, taking all the cases found. Man, dog, cat, horse,

cattle, sheep, goat, hog, deer, etc., are subject to the disease either

naturally or experimentally. The disease is confined commonly to dogs,

because the dog naturally attacks animals of his own species and thus

keeps the disease limited mainly to his own kind. Naturally the dog

follows this rule, but on the other hand, in the latter stages of the

disease he usually goes to the other extreme and even attacks his own

master, etc. The dogs that are the most dangerous and do the greatest

damage are of the vicious breeds.



The rabbit or guinea pig is used for demonstration in the laboratory.

Guinea pigs respond to the virus more rapidly than do other animals and

therefore they are especially useful in diagnostic work. Rabbits, however,

on account of the convenient size and ease with which they are operated

upon, are usually the choice in the production of material used in

treating patients.



The director of one Pasteur Institute says, "We have two classes of

patients to deal with in the Pasteur institute. The larger class, of

course, are those inoculated by the bite of rabid animals, but we also

have a few who are infected by the rabid saliva accidentally coming in

contact with wounds already produced. In these accidental eases the

disease is almost as likely to result as in those to whom the virus is

directly communicated by the bite." The wounds considered most dangerous

are the recent fresh wounds. The possibility of infection decreases with

the formation of the new connective tissue which protects the ends of the

broken nerve fibres. One must remember, however, that wounds over joints,

especially on the hands, are likely to remain open for some time. A dog

ill of this disease can give the disease to man through licking a wound.

Such a case has been recorded. This dog licked the child's hands before it

was known to be mad. The child died from the disease. As stated before

ninety per cent of the cases are inoculated by the bites of rabid animals.









The wounds are considered according to their severity and location.

Lacerating, tearing wounds upon uncovered surfaces, especially the head,

are the most dangerous. This is due to the fact of the closeness of the

brain and the large amount of infection in such a wound, and for this

reason treatment should be immediately given. But smaller wounds should

also be treated for the smallness of the wound furnishes no sure criterion

as to the future outcome of the disease. All possible infections should be

regarded as dangerous when considering the advisability of taking the

Pasteur Treatment. The small wound has usually a longer period of

incubation, because of the small amount of infection, still it may cause a

fatal termination. A dog never develops rabies from a lack of water or

from being confined or overheated during the summer months. A spontaneous

case of rabies has never been known. It must be transmitted from animal to

animal and the history of the case will point to a previous infection by a

diseased animal.



Where rigid quarantine rules exist the disease does not occur. In

Australia they quarantine every dog, that comes to that country, for six

months, and in consequence they have never had a case of rabies. In Russia

they have had many cases. In Constantinople the disease frequently "runs

riot." France has lost as many as 2,500 dogs in one year. Before the

Pasteur Treatment was instituted (in 1885) there was an average of sixty

deaths in human beings in the Paris hospitals.



Belgium and Austria average one thousand dogs annually. There was a yearly

average in Germany of four hundred dogs, dying of rabies, until the law

requiring the muzzling of dogs was strictly enforced and since that time

the disease is practically unknown. We do not have strict quarantine laws

against dogs, and the result is death from hydrophobia in many states

annually. It was formerly believed that rabies was a hot weather disease.

The number of cases during the winter months of late years has disproved

that belief, for the records of the institute for treatment of hydrophobia

at Ann Arbor have shown a decrease of cases during the summer months. This

was before 1908. This shows that rabies is not a hot weather disease.







Ordinarily cases of rabies occur here and there (sporadic), but if the

conditions are favorable epidemics break out. One dog may bite several

dogs and these dogs bite others and thus spread the disease to many. Not

every animal bitten by a mad dog develops the disease. The disease does

not always follow the bite. Only about forty per cent of all animals

bitten by a mad dog contract the disease. This is given by a noted

authority. Statistics also show that in man the disease develops in only

about twenty per cent of the cases in those who have been bitten by rabid

dogs. But in dealing with those who have been bitten such measures should

be taken as would be if they were certain of developing the disease; one

cannot tell how much poison enters the system in such cases and preventive

procedures should be taken. There are reasons why everyone who is bitten

does not contract the disease.



The location and character of the bite must be considered. Bites on the

head, neck and hands have been recognized as more dangerous, from early

times, and such bites produce fatal results quicker than do bites on other

parts of the body, and the reason is largely due to the fact that the

other parts of the body are more or less protected by the clothing, and

this clothing prevents the entrance of so much poison into the system.

Bites on the head give a high mortality rate and are rapidly fatal. The

close proximity to the brain is one reason.



The part the clothing plays in protection is clearly shown by the

following quotation from an eminent authority: "In India where the natives

dress very scantily, the mortality was exceedingly high up to a few years

ago, at which time the British introduced the Pasteur laboratories. The

clothing protects the body and it holds back the saliva and can be looked

upon as a means of filtering the saliva of the rabid animal, most of the

saliva is held back as the teeth pierce the clothing, so that upon

entering the flesh the teeth are practically dry, and only a portion of

the virus is introduced. Upon entering the wound this small amount of

virus is further diluted by the tissue juices to the non-infectious point.

We know from actual experimental work in the laboratory that the higher

dilution will not kill."



If a portion of the brain of an animal dead from street virus is taken and

made up in a dilution of one to five hundred, and this is injected, we

find that it does not produce death. But a dilution of one to three

hundred will invariably kill. This is practically what very often happens

when one is bitten through the clothing. The saliva may be filtered and

held back so that a small amount is introduced; perhaps a dilution of one

to five hundred of the virus may get into the wound, but this is usually

not enough to cause the disease. There is no possible way of estimating

the amount of the inoculation. In such cases one's chances of never

contracting the disease are only decreased; that is all we can say.



The treating of individuals, bitten by rabid animals, in the Pasteur

Institutes, is simply the practical application of results obtained by

Pasteur from his original work on rabies virus. Pasteur was a French

chemist living in Paris, and he began his search for the cause and cure of

rabies in 1880. He hoped to find a sure method of preventing the

development of the dread disease, even if he could not find a cure for it

after it had developed. While he was pursuing this research Pasteur had

access to the cases of rabies in the Paris hospitals, and these numbered

sixty each year. He had practically an unlimited supply, for France could

furnish him with twenty-five hundred more mad dogs, and a large number of

other animals each year.







Pasteur devoted the remainder of his life to the study of this subject. He

collected some saliva from the mouth of a child, on December 11, 1880, who

had died at the Hospital Trousseau four hours before. This saliva he

diluted with distilled water, and this mixture he injected into rabbits,

and they all died, and the saliva taken from these rabbits when injected

into other rabbits caused their death with rabies. He found also that

saliva from rabid dogs almost always caused the disease. The incubation

period varied within wide limits, and very often the animals lived. He

then used the blood of rabid dogs for inoculation, but these blood

inoculations always failed to produce the disease. Pasteur was convinced

after careful study of rabid animals during the many months necessary to

complete his experiments, that rabies was a disease of the nervous system,

and that the poison (virus) was transmitted from the wound to the brain by

the way of the nerve trunks. Then to prove his theory Pasteur removed a

portion of the brain of a dog that had died of rabies. A part of this was

rubbed up in sterile water and used to inoculate other animals; and

subcutaneous inoculations with this material almost always produced death.



After this Pasteur tried a new method and injected directly into the

nervous system, either into the nerve trunk or directly into the brain,

after trephining, and all such injections produced rabies in the injected

animal and death. He also found that rabbits inoculated in the brain

always died in the same length of time. When he injected into the nerve

trunk the inoculation period was longer, depending upon the distance from

the brain. Two problems now remained for Pasteur to solve, and these were,

how could he obtain the definite virulence and how could he reduce the

virulence regularly and gradually, so that it could be used by inoculation

safely as a vaccine to produce immunity to rabies in healthy animals, and

also to prevent the development of rabies in animals bitten by rabid

animals. He first tried successive inoculations. These inoculations were

made, after trephining, directly to the brain, and he used a portion of

the brain as a virus each time. He inoculated rabbit number one with a

portion of brain taken from a rabid dog, and this rabbit died on the

fifteenth day. He then inoculated rabbit number two with a portion of the

brain of rabbit number one; from the brain of rabbit number two the virus

was supplied for inoculating rabbit number three, and thus the brain of

each inoculated rabbit was taken, after its death, for material to

inoculate the next rabbit in the series. This experimentation showed him

that each rabbit in the series died a little sooner, showing that the

virus was becoming more virulent, till no increase in activity of the

poison was shown after the fiftieth successive inoculation. "Rabbits

inoculated with a brain suspension of rabbit number fifty all died in

seven days." This caused Pasteur to name the virus of number fifty "virus

fixe," a virus of definite length. He now had obtained a virus of definite

strength and the next question was, how could the virulence be gradually

and definitely reduced.







This he accomplished after many experiments. He proved that pieces of the

"medulla oblongata" suspended in sterile tubes which contained fragments

of caustic potash, steadily and gradually reduced their virulence as they

dried, till the fourteenth day, when they were practically inert. New

specimens were prepared each day and cords which had dried in one day

Pasteur called "one-day virus;" cords which had dried in two days, "two

day's virus," and so on up to the fourteenth day. With this graduated

virus he now experimented on dogs, and the injection he used on the first

day consisted of an emulsion of fourteen-day virus; for the second day,

the thirteen-day virus, thus using a stronger virus each day, until on the

fourteenth day he used the full strength virus. This treatment produced

what is called immunity in the dog, and even the direct inoculation into

the brain of the strong virus would not produce death.



After Pasteur had thoroughly satisfied himself by repeated trials, he

announced his wonderful discovery, and it was in 1886 that Pasteur

considered the preventive inoculation in human beings as resting upon a

satisfactory experimental basis. During these five years this eminent man

proved that it was possible to protect or immunize the lower animals,

rabbits and dogs, against inoculation with the virulent virus.



The efficiency of this immunity was given trials by different methods of

inoculation. It was found that sixty per cent of dogs inoculated under the

"dura" (a membrane of the brain) were saved if treatment was given the

second day. This test is more severe than is required to meet the ordinary

infection of rabies. Pasteur, after a series of these final tests were so

convincing, prescribed the preventive inoculations in human beings and on

July 6th, 1886, the first human patient received the first treatment of

his series of inoculations.



The method of obtaining the attenuated virus used in the treatment is as

follows: A rabbit is inoculated by the brain method before described, each

day, with suspension of the fresh, fixed virus. These rabbits die in six

days after the inoculation. In this way a rabbit dies each day; the spinal

cord is removed, divided into sections, and suspended in a flask

containing potassium hydrate. The action of potassium hydrate is drying

(desiccating). A series of these cords, which have been hung on fourteen

successive days, are always kept in stock for the treatment of patients.

The virus becomes less active with each successive day of exposure to

drying (desiccation) and finally the virulence is altogether lost.



When the patient comes for treatment the fourteenth and thirteenth-day

cords are used for the first inoculation, and on each successive day the

patient receives inoculation, the strength of which has been regulated by

the number of days the cord has been hanging. During the first four days

patients receive injections of six cubic centimeters of emulsions made

from cords aging from fourteen to seven days, and from the fifth day until

the completion of the course of treatment patients receive emulsions from

cords of higher immunizing properties, but no cords desiccated for less

than four days are used.







Death rate from 1878-1883 before Pasteur treatment was instituted taken

from documents in the department of the Seine:



1878 143 bitten. 24 deaths.

1879 76 " 12 "

1880 68 " 5 "

1881 156 " 22 "

1882 67 " 11 "

1883 45 " 6 "



Average of one death to every six bitten, or seventeen per cent mortality.





Incubation period from eleven days to thirteen months, average one hundred

and twenty days, depending upon location of bite. Pasteur Institute

records during the years 1886-1887 and first half of 1888, show that

Pasteur had under his supervision 5,374 persons bitten by animals either

proven or thought to have been mad. Mortality for 1886 was 1-34 per cent,

during 1887 it was 1-12 per cent, during 1888 it was 77/100 per cent. With

the later treatment the mortality has decreased to 3-10 per cent in 1908.

The Pasteur method of treatment is a process of immunization which must be

completed before the development of the disease. It is of no value after

the symptoms have appeared.



Those who have not been affected can be immunized the same as those who

have been bitten. The individual who has been bitten by a mad dog realizes

when and how severely he has been bitten, and were it not for the

so-called period of latent development of the virus, it would not be

possible to carry out the Pasteur treatment. The patient may, if he will,

take advantage of this fact and be immunized by treatment before the

disease has developed. Deep and severe bites are most dangerous, but the

disease may develop simply from a rabid dog licking a scratch of the skin.

As before stated bites on exposed or uncovered surfaces, are more

dangerous than those through clothing. There is a very easy access of the

saliva to the wound in the unprotected part, while in the protected parts

the teeth in passing through the protection, clothing, are freed of their

saliva at least partially. The virus is conveyed from the bitten part or

inoculation to the central nervous system through the nerve trunk, and the

rapidity of extension depends upon the resistant powers of the patient,

the virulence and the amount of virus deposited in the bitten part at the

time the person was bitten. This disease develops only in nerve tissues.

Virus can be found in the nerves of the side bitten, while the

corresponding nerves on the opposite side are free from it. It can be

ascertained that the virus is present in the medulla oblongata before the

lower portion of the cord.







Comparative danger. A wound of the hand after a delay of three weeks is

as dangerous as a bite on the head exposed only a few days. There is

always a possibility of an accumulative action and extension of the virus

along the nerve trunk to the central nervous system during the interval of

exposure, and this should be always borne in mind. It is stated by

authority that the virus is not transmitted by the bite of a rabid animal

until two days previous to the appearance of the first symptoms. It is

with some difficulty that a decision is reached in advising patients who

are bitten to take treatment early in the course of the disease. The

symptoms are often so very obscure and slight that they are not

recognized. If a dog which is not naturally vicious suddenly bites without

any cause it should be tied securely and watched for seven days; and

should it develop symptoms of the disease during this period the bite

should be considered dangerous.



Immediate treatment of the wound. A temporary measure is the

cauterization of the wound; do not neglect this because a few hours have

passed since the person was bitten, for wounds may be cauterized with

advantage even after two or three days have elapsed. Of course the earlier

it is done the better. If they are thoroughly laid open and scrubbed it is

more effective. Nitric acid used freely is the best method to use. Wash

the wound freely with boiled water after the acid has been applied;

ninety-five per cent carbolic acid may be used if nitric acid cannot be

obtained.



If carbolic acid is used it is necessary that it be washed from the wound

by the free use of absolute alcohol, followed by boiled water and a

dressing of bichloride of 1-7000. This prevents the ulceration of the

wound by the carbolic acid. Cauterization thoroughly done destroys a part

of the inoculated virus. Thorough cauterization is especially necessary

with large wounds in which large quantities of the virus is inoculated.



When to send patients to an Institute. Send them immediately, if there is

good reason to believe the animal had rabies. It is not wise to wait until

the animal dies; it is very important that treatment is begun as soon as

possible, especially in severe bites.



What to send for examination. The entire head may be sent by express, or

better, the health officer should bring it in person. This saves time and

relieves anxiety; or a portion of the brain may be removed under

thoroughly clean conditions and placed in a sterilized twenty per cent

solution of glycerin and water. In this way the virus retains its

virulence and putrefaction is diminished. The first method is the best,

taking the head directly. The head after it reaches the laboratory is

examined microscopically for "negri bodies," and if there is no

contamination the microscopic findings are verified by animal

inoculations. The presence of negri bodies in a specimen is of great value

owing to the rapidity with which a diagnosis can be made. In one case a

positive diagnosis was reported within twenty minutes after the specimen

entered the laboratory and within the next hour and a half the patient

bitten by the dog the same day had begun her course of protective

injections and was saved.







Protection. To stamp out this disease city authorities, etc., can enact

laws. All ownerless dogs should be killed, and the keeping of useless dogs

should be discouraged by taxation. All dogs should be thoroughly muzzled

where the disease prevails. This article is made up from an article

written by an acknowledged authority on this disease, a man in charge of a

Pasteur Institute.



Cities where Pasteur Institutes are located:

Ann Arbor, Michigan. Baltimore, Maryland.

Chicago, Illinois. Austin, Texas.

Minnesota. Toronto, Ont.

New York City.



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