The prognosis is favorable save in advanced instances of the disease. With-
out proper treatment the duration of a single infection has been, in one
case, followed for six years and seven months (Stiles); how much longer
it may last has not been shown. If the patient is subjected to reinfection the
disease may continue for fifteen years or even longer. Fatalities are not very
rare in severe and prolonged infections which have not received proper treat-
ment.

Treatment. Uncinariasis may be prevented to some extent by disinfection
of faeces, by thorough washing of the hands, after having to do with earth or
water which may contain the uncinaria, and by boiling all drinking water.

The most efficient anthelmintic in uncinariasis is thymol; this drug is best
administered as follows: After having placed the patient upon fluids (milk
and soup) for three days, 30 grains (2.0) of thymol are given at 8 A. M.; at
10 A. M. the dose is repeated and two hours later a purge is given, preferably a
saline; castor oil dissolves thymol and the solution of this agent within the
body may cause toxic effects; for the same reason alcohol should not be given
with the thymol as has been recommended. After a week the stools should
be examined and if ova are still present the treatment shoiild be repeated
until they disappear but it is better not to administer thymol oftener than
once a week. It is very important to be certain that no eggs are to be
found in the faeces before discharging the patient as cured.

Thvmol carbonate has been suggested as a substitute for thymol but probably
offers no advantages over the former drug; male fern is also advocated.

The treatment of the anaemia is that of secondary anaemia from other
causes (q. v.), iron and plenty of nourishing food in connection with other
tonics being indicated. It is considered best to omit the iron upon the days
when thymol is given (Stiles).



TRICHINIASIS, 86 1

TRICHINIASIS.

Synonym. Trichinosis.

Trichinosis, the term applied to infection with the trichina spiralis is
acquired by eating the meat of infected hogs. The parasite is cylindrical in
shape, the length of the male being about -^ of an inch (from 1.4 to 1.6 mm.);
the anterior extremity tapers to a point while the posterior extremity is thick-
ened and bifid, each lateral appendage being somewhat conical. The length
of the female is about three times that of the male and the tail is rounded.
The larvEe when born are from 90 to 100 /i in length, blunt anteriorly and
pointed at the caudal extremity. Muscle trichinae, the encysted larvae, are
about I mm. long and 0.04 mm. in thickness, tapering anteriorly but obtuse
posteriorly; they lie coiled in an ovoid capsule which is at first transparent
but becomes opaque as a result of calcareous infiltration.

In the adult sexual stage the trichina spiralis inhabits the intestine of man
and other animals such as the hog, rat, mouse, guinea pig, rabbit, cow, sheep,
horse, dog, cat, etc. The parasite is also found in the hen, duck and pigeon.
In the intestine of its host the trichina gives origin to a great number of
larvEe, after which the adults perish and the larvae migrate to the intermus-
cular tissues and finally into the substance of the muscles where they develop in
about fourteen days into the mature muscle form, setting up, during the process,
an interstitial myositis and ultimately becoming encysted in an oval capsule
which may contain from one to four of the coiled larvae. The cyst wall is
transparent at first and about 0.4 mm. by 0.25 mm.; the capsule gradually
thickens and becomes infiltrated with calcium salts, this process taking place
in from five to eight months and sometimes involving the larva itself. The
encysted larvae may live within the muscle of the hog for eleven years and in
that of man for as long as forty years.

The human being usually acquires trichiniasis by eating infected pork
which has been cooked insufiaciently to destroy the parasite. In the intestine
the capsules of the encysted larvae are dissolved by the digestive secretions
and their contents is set free. In the intestine they develop into the adult
worm in about three days. After fertilization has taken place the males
perish while the females, adhering to the intestinal mucosa or penetrating the
wall of the gut, migrate to the mesentery or the lymph glands of this structure.
Each female is capable of giving birth to a great number of larvae which leave
the intestinal tract in the lymph ciirrent and find their way to the muscles
either in the blood stream or by direct migration.

Trichiniasis is most common in Germany where the use of raw or imper-
fectly cooked pork in the form of sausage is frequent. Pickling or smoking
infected meat is not effective in destroying the parasite but thorough cooking
will accomplish this object. In the United States the disease is somewhat



862 PARASITIC DISEASES.

rare, Stiles, who has made a special study of the subject, stating that up to
1898 not more than 900 cases have been reported. It is probable that many
instances of the affection are undetected for many of the reported cases were
unsuspected, the parasite being revealed after autopsy, death having occurred
from other causes.

Patho]ogy. The morbid changes are chiefly in the striated muscle fibre
and consist of a localized myositis characterized by granular degeneration
and nuclear proliferation. The cysts are present in the muscles, appearing
to the naked eye as small grayish oat-shaped bodies placed longitudinally in
the muscular fibres, and the adult parasites may be found in the intestine.
Enlargement of the mesenteric glands and fatty degeneration of the liver
have been observed. Important blood changes occur and will be considered
later.

Symptoms. The presence of trichinae in the intestinal tract may not be
followed by the disease, for the parasites may be passed off by the bowel
before they have had time to mature and reproduce themselves; also the
migration of only a few larvae may not be characterized by noticeable
symptoms.

Following the ingestion of numerous trichina larvae symptoms of gastro-
intestinal irritation may appear within three or foiir days; there may be nausea,
vomiting, abdominal distress and diarrhoea; general malaise with prostra-
tion and pains in the bones and muscles may occur. These prodromal mani-
festations may be wholly absent or, on the other hand, so severe as to be mis-
taken for cholera morbus. The invasion of the disease takes place in from
a week to ten or even fourteen days; it is usually characterized by a rise in
temperature to 103° to 104° F. (39.6° to 40° C); the temperature curve is of
remittent or intermittent type and is seldom associated with chills. In mild
types of the infection there may be no fever. The migration of a large number
of larvae in the muscular tissue, as stated above, causes a myositis which is
evidenced by muscular pain, increased upon pressure and active and passive
movement, and swelling, with cutaneous oedema, appearing first in the eyelids
and later in the extremities and trunk. This symptom may last several
days and disappear, to recur after a week or less. The involvement of the
muscles of the jaws, throat and larynx, may result in painful and difficult
mastication, deglutition and phonation, while the myositis of the diaphragm,
thorax and abdomen is accompanied by dyspnoea and painful respiration.
Sweating and cutaneous pruritus are not uncommon and urticarial and other
eruptions have been observed. Nervous symptoms such as headache, sleep-
lessness, pupiUary dilatation and transient loss of the tendon reflexes some-
times occur. In prolonged instances of the disease emaciation and anaemia
are noted. Increased urine and albuminuria have been common in certain
epidemics.



TRICHINIASIS. 863

The patient, in instances of very severe infection, may fall into the typhoid
state, with its typical manifestations.

The blood usually exhibits a varying degree of leucocytosis and, what is
much more important and characteristic, a marked eosinophilia, the number
of eosinophiles being in direct proportion to the severity of the case.

The diagnosis of sporadic cases presents certain difl&culties on account
of the resemblance of the disease to enteric fever and muscular rheumatism,
but if a number of patients are stricken at once with characteristic symptoms,
particularly after possible exposure such as an occasion where many persons
have partaken of ham or sausage, suspicion should at once be excited. Differ-
ential blood counts should be made immediately and the intestinal mucus,
a mild laxative having previously been given, should be examined for the
parasites which may be seen with a low power lens as small, glistening, thread-
. like bodies. The dyspnoea, muscular pains, tenderness and swelling, and the
oedema are important diagnostic signs. If the diagnosis is doubtful bits
of muscle should be removed from the deltoid or pectoralis major, under
cocaine or other local anaesthesia, and examined microscopically. A special
instrument has been designed for the excision of the muscular tissue.

The prognosis depends upon the number of larvse which have been eaten
and upon the number of adult parasites which develop in the intestinal tract.
In the milder infections recovery is usual within two weeks; marked gastro-
intestinal irritation is considered to augur well for the patient. In severe
instances of the disease the illness may be protracted for two months or more
and is followed by a very slow convalescence. The death rate varies in differ-
ent epidemics from i to 25 or more percent.; the fatal issue may occur as
late as the sixth week.

Treatment. The prevention of trichiniasis consists in the inspection of
the carcasses of all hogs slaughtered for food and the destruction of those
found infected. The importance of clean surroundings for their stock should
be explained to those who raise swine for market and also the necessity of
proper feeding. While it is not certainly known how hogs become infected
it has been suggested that the infection may be transmitted from the rats
which thrive about abattoirs, consequently the destruction of these animals
in slaughter-houses and about pig styes is advisable. Finally complete
prophylaxis may be achieved by the thorough cooking of all ham and sausage.

If the patient is seen early in the disease free evacuations of the intestinal
contents should be secured by means of large doses of calomel (followed by a
sahne), rhubarb, senna, aloin or other pinrgative, with the object of freeing
the bowel from the parasites there present. With the purges anthelmintic
drugs such as santonin, male fern or thymol should be given. It is important
that the bowels should be kept freely open for at least a week after infection
has taken place. Glycerin in doses of a half ounce (15.0) every hour has been



864 PARASITIC DISEASES.

recommended. We know of no means to destroy the larvae within the mus-
cles, but the use of picric acid in doses of from 5 to 8 grains (0.33 to 0.5)
has been suggested.

The treatment otherwise consists in the employment of measures calculated
to relieve the symptoms. The muscular pains may be relieved by means of
hot baths or applications of anodyne liniments, equal parts of hydrated chloral,
camphor and menthol, for instance, with hypodermatic injections of morphine
should these become necessary. The restlessness and sleeplessness may be
controlled by the bromides, sulphonmethane (sulphonal), sulphonethylmethane
(trional) and similar drugs. During the febrile stage the diet should consist
of nourishing fluids and upon the establishment of convalescence tonics, such
as strychnine, quinine and iron, with massage and electricity to combat the
excessive muscular weakness, are indicated.

FILARIASIS.

A number of different filariae claim man as their host. Of these the most
common are the three species which are included under the term filaricB
sanguinis hominis.

1. Filaria Bancrofti, the most frequently found blood filaria, occurs in most
tropical regions. It has been observed in East India, China, Japan, the
Malay Archipelago, the South Sea Islands, Australia, Africa, and the West
Indies, as well as in the Southern United States. The male parasite is about
ij inches (4 cm.) in length and 3-^-0 of an inch (o.i mm.) in thickness; the
anterior extremity is slightly clubbed, the posterior extremity tapering and
spirally twisted. The female is bro\\Tiish, about twice the length and thickness
of the male and possesses rounded extremities; the ova are 38 /j. by 14 //.
The embryos measure from 270 to 340 /i in length by 7 to 11 ju in breadth;
their especial peculiarity is that they are found in the blood at night only,
except in the case of individuals who sleep during the day, when they are
present in the circulation during the hours which the host spends in sleep.

2. Filaria diurna is found in the blood during the waking hours only and
is to be differentiated from /. Bancrofti by this fact and the absence of granules
in the axis of the larva. Manson who first described this form of filaria
suggests that it is the larval form of filaria loa.

3. Filaria perstans is also known only in its larval form and is found at all
times, day or night. The embryos are smaller than those of the preceding
varieties, being about 200 fx in length. It is actively motile and has an
abruptly rounded and truncated posterior extremity; the anterior extremity
is retractile and possesses a prominent spicule. This parasite is possibly the
cause of craw-craw, an ulcerative skin eruption which occurs in west Africa.



FILAEIASIS. 865

F. Bancrojti is the most important of the above described parasites and to
its presence in the human body hcBmatochyluria and elephantiasis or lymph
scrotum are attributed.

The embryo filariae enter the blood stream by means of the lymphatics
and being no larger in diameter than the thickness of a red blood cell are
easily passed through the finest capillaries; although enclosed in their sheaths,
they are actively motile and may be easily seen in specimens of fresh blood.
During the day they are not found in the blood except in very exceptional
instances or when the patient is accustomed to sleep in the daytime and work
at night. At night they are present in the blood stream in great numbers.

The life-history of the parasite is not very definitely known but it is supposed
that they are withdrawn from the circulation by the mosquito. The larvse
develop to some extent in the stomach of the insect and then migrate, finding
their way into the thoracic muscles. Upon the death of the mosquito the
larvae are set free in the water in which the insect has died, to be later drunk
by human beings, according to the older theory, and entering the digestive
tract bore through its walls into the lymphatic vessels. The larv^ have
been found in the proboscis of the mosquito and the more probable method
of transmission is by means of the bite of this insect and consequent direct
infection.

Symptoms. Large numbers of filariae may be present in the blood with-
out giving rise to suggestive manifestations or prejudicing the health of the
host; on the other hand certain pathological effects may be produced.

HcBmatochyluria. If the parasites cause stoppage and obstruction of the
lymph circulation a lymph fistula may open into the ureter or bladder
and the urine becomes milky {chyluria) from the admixture of chyle and if,
as a result of the development of this fistulous opening, there is a rupture of
blood-vessels, blood also appears in the vocme {hcBmatochyluria). Without
other symptoms or marked disturbance of health, the patient passes at intervals
opaque milky urine which may show an admixture of blood. The urine is
otherwise normal in its constituents but at times may be increased in amount.
In the intervals of the chyluria the urine is of ordinary character. The
passage of the chylous and bloody urine may be associated with lumbar pain.
Under the microscope the milky urine is seen to contain fat globules, red blood
cells, and sometimes motile filarite.

Lymph Scrotum, Lymph Vulva and certain types of elephantiasis may result
from the presence of the filariae. The affected parts are swollen and thickened
and contain plainly visible and distended lymph vessels; these are found to
contain a milky, turbid or blood-stained fluid which coagulates on standing.
Filariae are sometimes present in the fluid. The inguinal and femoral glands
may be swollen and soft. Erysipelas infection of the affected tissues may
occiir and may be accompanied by chills, fever and sweating.
55



866 PARASITIC DISEASES.

In connection with the conditions described above, blood changes, such as
anaemia and eosinophilia, splenic enlargement and interference with general
nutrition, have been observed.

Treatment. The prevention of filariasis is, to some degree, possible by
boiling the water used for drinking and in the preparation of food, by de-
stroying mosquitoes and by preventing the access of these insects to human
beings by means of bed screens, etc.

There is no certain method of destroying the filarije in the body although
good results have followed the administration of thymol in doses of i to
5 grains (0.065 ^^ °-33) given for a period of several weeks; benzoic acid,
sodium benzoate and methylthionine hydrochloride (methylene blue) in 4
grain (0.25) doses have been recommended by certain observers. Chyluria
necessitates temporary confinement to bed, an avoidance of fluids and fats,
and the administration of saline purges to lessen the tension in the lymphatic
system. Such treatment may result in the temporary disappearance of the
chyle from the urine. If fats are omitted from the diet the urine may continue
normal but the administration of a glass of milk is often followed by a recur-
rence of the turbid urine, proving that the lymphoid fistula is still patent.

The surgical removal of the adult parasites from the inguinal or other
accessible glands is often of pronounced benefit and is unattended with danger.

DRACONTIASIS.

Synonym. Guinea-worm Disease.

Filaria or Dranunculus Medinensis {The Guinea-worm) is a common
parasite in the tropical and subtropical parts of Asia, Africa and America.
The female only has been observed; it is whitish or yellowish in color, from
20 to 28 inches (50 to 80 cm.) in length and from ^ to -j an inch (0.5 to 1.7 cm.)
in thickness. Its anterior extremity is rounded and supplied with a two-
lipped oral orifice. The tail tapers to a blunt point bent into the form of a
hook. The male is believed to be much smaller. The larvae are supposed
to enter the alimentary tract of the host in drinking water, being enclosed
in the bodies of certain small arthropods (cyclops) or free, having gone through
several stages of development inside this latter organism. The theory that
the parasites may enter the body by penetrating the skin has also been sug-
gested. Probably the male and female are ingested but the former dies after
having performed the function of impregnation, while the female, containing
a very large number of embryos, penetrates the intestinal wall, and migrating
to the subcutaneous tissues, still further develops. It may remain quiescent
and is palpable under the skin; later the parasite finds its way downward
through the tissues to the ankle or foot. This migration is probably in re-



DRACONTIASIS. 867

sponse to a desire to allow the embryos to- escape. When the sought for
situation has been reached the head is thrust through the skin, caus-
ing a small vesicle which is surrounded by a more or less inflamed area.
The vesicle ultimately bvirsts, leaving an ulceration, at the base of which the
head of the parasite may be demonstrated. Having discharged the embryos
the parasite leaves the body. Usually there is but a single worm in one host,
although this is not always the case.

Symptoms. These are those of a locaHzed inflammation at the site of exit
of the parasite; there may be a slight febrile movement but this is only tran-
sient if cleanliness is observed after removal of the parasite. If the worm
is torn during its removal suppuration with the usually associated symp-
toms is said to be a very probable resiflt.

Treatment. Prevention consists in the thorough filtering and boiling of
drinking water and in avoiding contact with muddy water in which the Cyclops
may be present.

The natives of the countries where the guinea-worm is common as a rule
moisten the iflcerated bases of the ruptured vesicles and, when the head of
the parasite is extruded, it is fastened round a bit of wood which is gradually
twisted until after several days the entire worm is withdrawn. Injection
of mercury bichloride solution (i to 1000) into the head will kill the parasite
after which it may be readily pulled out. Injections of mercury into the
tissue adjacent to the worm also kill it and it may be removed by excision.
The wound should be dressed antiseptically; in this connection i to 15
phenol solution is recommended but should be carefully watched lest it
cause gangrene of the part. The local application of the leaves of the "arma-
pattee" plant is recommended by native physicians in India and large doses
of asafoetida are said to be fatal to the parasite.

Other filariae have been found in man but much less frequently than
those pre\^ously described. Of these the following are worthy of brief
mention.

Filaria loa occurs in West Africa and exists in the subcutaneous tissues,
especially those of the face, where it wanders about causing burning and itching.
It is particularly frequent beneath the conjunctiva where it induces swelling
and inflammation. This parasite has been found in the Western Hemisphere
whither it has probably been brought by African slaves.

Filaria immitis. This is a common parasite in the dog and has been found
in the portal vein of man, the eggs being present in the walls of the ureters
and bladder.

Filaria Bentis has been observed in a cataract. Filaria trachealis and
bronchialis has been observed in the trachea, bronchi and lungs. Filaria
labialis has been demonstrated in labial pustule and Filaria hominis oris
has been found in the mouth.



868 PARASITIC DISEASES.

TRYPANOSOMIASIS.

Trypanosoma hominis, the organism which is believed to be the cause of
African sleeping-sickness, has been discussed in the section upon infectious
diseases.

^ CESTODES.

ECHINOCOCCUS DISEASE.

Synonym. Hydatid Disease.

The taenia echinococcus has been described in the section upon diseases
of the liver. Echinococcus diseases of the lungs, spleen and other organs
have been discussed in the sections devoted to the affections of the organs in
question and to these the reader is referred.

INTESTINAL CESTODES, T^NI^ OR TAPE-WORMS.

Various types of taeniae are found in the human intestine as a result of the
ingestion of the undeveloped larvae vT^hich occur in the muscular tissue or
other organs of animals. The ova of the tape-worm pass from the intestine
of the host in the dejections and are taken into the bodies of various animals
where they become fixed in the muscles or other tissues, probably being trans-
ferred thither by the blood or lymph currents. Within a few months after
lodgment the ova develop into cysticerci or bladder -worms; these present the
following characteristics. The cysticercus is inclosed in a thin connective
tissue wall within which lies the bladder-worm, which really is the head of
the future tape-worm and is termed the scolex. Behind the head there is a
constricted neck consisting of undeveloped segments, the terminal one being
distended into a bladder-like body. In some forms of taenia the ova may
become encysted in the intestinal wall of the original host and subsequent
development of the full-grown parasite in the intestine results in an auto-
infection; more commonly, however, there is an intermediate host in the
tissues of which the larvae develop and are finally eaten by a third host to
whose intestinal wall the parasite, its cyst wall being removed by the action
of the digestive fluids, becomes attached and gives origin to segment after
segment, thus forming a new taenia.

Taenia Mediocanellata, Tcenia Saginata or Beef Tape-worm is the most
common variety of tape- worm in this country; it is also frequently found in
other parts of the world, especially where beef is largely consumed. Its
usual length is from 3 to 8 yards (3 to 8 meters); its head is four-sided
and pear-shaped and possesses no hooklets or rostellum, but in place of