Chapter XXI: Ancylostomiasis

HISTORY AND GEOGRAPHICAL DISTRIBUTION

=History.=—It is very probable that hookworm disease existed in Egypt in the remote past and it has been claimed that a disease mentioned in the Ebers Papyrus was of that nature.

Goeze found a hookworm in a badger in 1782. He named the parasite
_Ascaris criniformis_. Froelich, in 1789, found hookworms in
the fox and named them hookworms from the hook-like ribs of the
copulatory bursa. He proposed the generic name _Uncinaria_.
Therefore _Uncinaria_ belongs to the hookworms of the fox and is
not valid for any human species.

In 1838, Dubini noted that these worms were generally found in
very anaemic cases and that the mucosa of the duodenum or jejunum
frequently showed punctate haemorrhages. On account of the four
ventral teeth projecting from the mouth he gave it the name
_Agchylostoma_ or correctly _Ancylostoma_.

In 1854 Griesinger, as a result of frequently noting the lesions
produced by the worms, stated that they were the cause of Egyptian
chlorosis. In 1866, Wucherer connected hookworms with a disease
of Brazil called opilacao. In 1878 Grassi noted that the disease
could be diagnosed by the finding of the characteristic eggs in the
stools of patients.

It was the prevalence of a severe anaemia among the workmen employed in the construction of the St. Gothard tunnel, which Perroncito proved to be due to hookworm infection, that established the great importance of this parasitic disease as the cause of a severe and fatal anaemia (1879). About the same time it became generally considered that the anaemias which affected workmen in mines were of a similar nature.

That the disease was very prevalent in the Southern States of the
U. S., as long ago as 1849, is shown by the writings of Duncan,
who noted the frequency of anaemia, often associated with dirt
eating, among the slaves. He described the oedematous legs, the
protuberant belly and cardiac palpitation. There were several
cases reported in the U. S. from 1893-1897 but they were mainly in
foreigners.

From 1895 to 1901, Stiles kept insisting that hookworm disease
should be of frequent occurrence in the U. S.

A. J. Smith found several cases in persons living in Texas and
recognized the fact that these hookworms were different from
those of Europe. It was from a study of material from Smith and
Claytor in the U. S. and, later on, from Ashford in Porto Rico,
that Stiles, in 1902, reported a new genus of hookworm as existing
in man. It was first named _Uncinaria americana_ but _Uncinaria_,
belonging to the hookworm of the fox, was not valid, so he changed
the name to _Necator americanus_.

=Geographical Distribution.=—The disease is rare outside the
tropical and subtropical countries except in mines or tunnels where
suitable conditions of warmth and moisture exist.

It is extremely prevalent in India and Egypt as well as in China
and other parts of the East. It is a very important infection
in Porto Rico and the Philippine Islands. It is extensively
distributed in South America, especially Brazil, as well as in
Central America, Mexico and the Southern States of the U. S. The
inhabitants of many of the islands of the Pacific are heavily
infested. Hookworm disease is common in southern Europe.

ETIOLOGY AND EPIDEMIOLOGY

=Etiology.=—The hookworm infections of man come almost entirely from two parasites, _Ancylostoma duodenale_, the Old World species, and _Necator americanus_, which is generally called the New World species from its having first been reported from the U. S. by Stiles. Hookworms belong to the class Nematoda and family Strongylidae.

Quite recently Lane has reported a new species, _A. ceylanicum_, as
having been obtained from 3 men in Bengal, after treatment. This
species is the one that infects the civet cat in Ceylon. So far as
we know the other human species belong solely to man.

The male hookworms are a little more than ⅓ of an inch (9 mm.) long and the females a little more than ½ inch (13 mm.) in length. The males can readily be distinguished by their posterior, umbrella-like expansion or copulatory bursa. The tail of the female is pointed. The vulva of _A. duodenale_ is located in lower half of the ventral surface; that of _N. americanus_ in upper half. The large, oval mouth of the Old World hookworm has four claw-like teeth on the ventral side of the buccal cavity and two knob-like teeth on the dorsal aspect. It also has a pair of ventral lancets below the four ventral teeth. One cannot make out a dorso-median tooth. In _N. americanus_ the buccal capsule is round, smaller and the ventral teeth are replaced by chitinous plates. Dorsally there are two similar but only slightly developed lips or plates. A very prominent, conical dorso-median tooth projects into the buccal cavity. Through it passes the duct of the dorsal oesophageal gland. There are also 4 buccal lancets. The copulatory bursa of the _Necator americanus_ is also different, being terminally bipartite and deeply cleft in the division of the dorsal ray, rather than tripartite and shallow, as with _A. duodenale_.

The anterior extremity of _Ancylostoma_ bends in the same direction
as the general body curve while that of _Necator_ hooks back in an
opposite direction to the body curve.

By dropping the worms, while still alive, into hot 70% alcohol they
readily assume the attitudes noted above.

In general, _Ancylostoma_ is larger and thicker than _Necator_.

The name hookworm was given to these nematodes from the hook-like
processes of the ribs of the rays of the copulatory bursa.
Dubini called the Old World parasite _Agchylostoma_, properly
_Ancylostoma_, on account of the 4 formidable hook- or claw-like
ventral teeth of the buccal capsule. (αγχὶλος, hook, and στομα,
mouth.)

_A. ceylanicum_ is somewhat smaller than _A. duodenale_ and in the
copulatory bursa of the male we have a deeper cleft in the dorsal
ray and 2 rather long tips to each branch instead of the shallow
cleft and 3 stumpy processes of the 2 branches as in _A. duodenale_.

=Life History.=—The delicate-shelled eggs pass out in the faeces, and in one or two days a rhabditiform embryo (200 × 14 microns) is produced. The mouth cavity of the embryo is about as deep as the diameter of the embryo at the posterior end of the mouth cavity; that of _Strongyloides_ is only about one-half as deep as the diameter.

As a practical point, the anaerobic conditions in the intestines
seem to prevent development of the hookworm ova or at any rate
the absence of the oxygen, so necessary for the segmentations
preliminary to the formation of the embryo, prevents it. Therefore
hookworm ova in freshly passed faeces never show other than
commencing segmentation while development of the larvae of
_Strongyloides_ takes place in the intestines, so that in freshly
passed faeces we find, generally, actively moving larvae or at
least eggs containing fully developed embryos. Hookworm ova very
rarely show more than 4 segments or exceptionally 8 segments in the
freshly passed egg.

In the presence of oxygen these ova rapidly develop into larvae,
particularly at a temperature of about 27°C. Beyond 37°C. and below
14°C. development does not seem to take place.

The rhabditiform larvae grow rapidly and by the 3rd day are about
300 microns long and undergo a primary moulting. By the 5th day
the bulb-like swellings disappear and the larva becomes possessed
of a straight oesophagus, thereby becoming a strongyloid larva. It
then undergoes a 2nd ecdysis or moulting, but instead of casting
off this old covering, it retains it as a protecting sheath. The
full grown larva is about 550 by 24 microns. At this time it ceases
to take food but can move actively in its sheath so that it can
crawl up blades of grass or vertical sides of mines. They can live
in this state for months, when moisture and shade are present, but
are rapidly killed by drying. Before becoming encysted hookworm
larvae are readily destroyed by the action of the sun or chemicals
or even by dilution of the faeces, especially with urine. Cort and
others have found it a common occurrence for mature larvae to lose
their sheaths while living in the soil, and to continue their lives
in the unsheathed state. The proportion losing their sheaths varies
from 52 to 98%.

This is the _infecting stage_ in which the larvae bore their way into the skin, which is the usual method of infection, or, occasionally, by entering the mouth on vegetables or otherwise.

Looss thought that they entered the skin by way of the hair
follicles but the idea now is that they can bore into any part of
the skin. It only requires a few minutes for the larvae to enter
the skin. From the subcutaneous tissues they effect an entrance
into lymphatics or veins, go to the right heart, thence to lungs.
From the alveolar capillaries they pass into the pulmonary alveoli,
thence up the bronchi and trachea, to pass out of the larynx and
then down the oesophagus to the stomach. The larva loses its
protecting sheath in the stomach and in a few days develops a
provisional buccal capsule.

By the end of the 2nd week, after another ecdysis, the larvae
have grown to be about 2 mm. long and 130 microns broad and in
about 4 weeks become adults, usually in the jejunum, where, after
fertilization of the females by the males, the giving off of
eggs begins. The adults attach themselves to the mucosa of the
intestine, feeding on the deeper structures of the mucosa, or on
the tissues of the submucosa. Sambon believes that the larvae can
work their way into the jejunum without going there by way of the
trachea and oesophagus.

By providing an exit to the trachea, Fülleborn demonstrated that
in dogs, infected with the dog hookworm, great numbers of larvae
poured out of the trachea. In other dogs he stitched the oesophagus
to the skin and noted larvae coming out of these openings. In these
dogs, with the ordinary channel obstructed, infection did occur
with, however, only a few worms, thus showing the truth of Sambon’s
views but at the same time demonstrating the unimportance of such a
route of infection.

The mouth cavity of the embryo is about as deep as the diameter
of the embryo at the posterior end of the mouth cavity, that of
_Strongyloides_ is only about one-half as deep as the diameter.
The genital anlage of _Strongyloides_ is much larger than that of
_Ancylostoma_.

=Epidemiology.=—When faeces containing hookworm eggs are deposited where conditions of moisture, warmth and shade exist, they develop into the infecting stage, which is the nonfeeding but motile larva inside the cuticle formed by the second moulting. While eggs and younger larvae are killed rapidly, the encysted larvae withstand drying for considerable periods.

Stiles notes that the more favorable conditions for development are
in a porous, sandy soil rather than in a clay one. Where a sewerage
system exists there is very little danger of the spread of hookworm
disease and the same is true where there is proper disposal of the
faeces by burning, boiling or treatment in a septic tank. In rural
districts, however, where the stool is often deposited in the shade
and retirement of a clump of trees, the soil becomes infested with
myriads of larvae, so that one standing with bare feet on such a
spot easily becomes infected. It is for this reason that shoes are
of protective value. In infected mines with temperatures below
22°C. infection is rare (6%); from 22°C. to 25°C. more common
(16.6%), and above 25°C., it may reach high figures (61%).

Those of the negro race do not suffer from the infection as do the
whites. They appear to have an immunity but serve as carriers of
the disease. There is difference of opinion as to the length of
time the parasites may live in man in the absence of reinfection.
Some consider this period one of a few months, others of two or
three years. We can certainly consider that a case leaving an
infested region will get rid of his parasites within seven years.

PATHOLOGY

The site of entrance of the larvae is characterized by a dermatitis which is often called “ground itch” or “foot itch” by reason of its frequent location in the foot which has come in contact with the faeces-polluted soil. The dermatitis disappears in about two weeks unless some secondary infection occurs. There are reports of pulmonary irritation which may be explained by the wandering of the larvae through the lungs.

Pronounced anaemia with yellow, wax-like skin is a feature of
severe cases but emaciation is rare, the subcutaneous fat still
remaining. There is frequently oedema about the ankles. In the
jejunum we find small haemorrhagic spots from the size of a pea
to that of a half dollar. A worm may be found in the center of
this spot. In sections from the tissues injured by the bite we
note an infiltration of eosinophiles. The heart often shows fatty
degeneration with dilatation. The liver and kidneys usually show
fatty change while the spleen is generally shrunken. Sandwith noted
splenic enlargement in many of his autopsies but such enlargement
must have been due to other causes.

There are many views as to the manner in which the damage due to the hookworm is brought about. Some think it by bacterial infections occurring through the wounds made by the worms, others that it is due to a haemolytic toxic material excreted by the worms, while Stiles considers the ingestion of the patient’s blood important. Looss thinks it due to the gradual destruction of the intestinal mucosa from the feeding on this, and especially of the submucosa, by the worms. In their feeding the worms move from site to site. When they leave a point bleeding continues and this may account for much of the anaemia.

On the side of the blood we have at first a moderate leucocytosis
which disappears with the anaemia. Eosinophilia and Hb. percentage
reduction are often observed. In 3 cases I have known a fatal
pernicious anaemia to develop.

SYMPTOMATOLOGY

In a secondary anaemia, with early and marked cardiac palpitation together with epigastric tenderness and a tendency to mental retardation and physical deterioration, one should always examine the stools for hookworm eggs.

The course of the disease is decidedly insidious and indefinite
and the clinical diagnosis notoriously uncertain, as shown by many
reports where physicians of experience, after examining a number
of persons in a mill or school and only diagnosing 2 or 3% as
infected, have been astonished, upon examination of the faeces of
the group, to obtain positive evidence of infection in 70 to 80% of
the number examined.

For convenience, it is well to divide hookworm cases into 3 groups; 1. Where the person infected fails to show any special evidence of abnormality, the diagnosis resting almost entirely on the finding of ova in the faeces.

Such cases may show very slight reduction in haemoglobin and
only admit of a certain lack of energy. The best indication that
hookworm infection is doing the host injury is that after treatment
they gain in weight and energy and show improvement in mental
concentration.

2. Mild cases with moderate degrees of anaemia, the Hb. percentage ranging from 55 to 75. In these cases there is rather marked epigastric tenderness with frequent attacks of acid eructations. Cardiac palpitation and a tendency to shortness of breath may be quite noticeable. Headache and vertigo may be present.

3. Severe cases. In such cases we may find extreme anaemia with Hb. percentages around 35 or even as low as 15. I have always felt that one was only approximating when recording percentages of 10 or lower.

These cases are very weak and show marked cardiac palpitation and
dyspnoea upon the slightest exertion. There is often dilatation of
the stomach and a protuberant abdomen. The red cells may fall below
1,000,000. There is also oedema, especially about the feet and
ankles. Tinnitus aurium is rather frequent.

Such cases often show depravity of appetite, the best-known craving being that for earth. Other patients crave chalk, wood, cotton, etc.

It is in children that we have the most serious effects of
the disease, there being marked stunting of the growth with a
corresponding mental backwardness. Such children show marked
retardation and delay in answering the question asked them and
often repeat it in a drawling manner. Tested by the Binet-Simon
method we may find a sixteen year old child to have the mental
development of a ten year old one, but at the same time we would
note that from a standpoint of physical development the child only
seemed ten years old.

As the child approaches adult age we note a striking lack of sexual
development and the lack of pubic hair. In girls there is delay in
the onset of the menstrual periods or these may never appear.

In from 80 to 90% of cases there is a history of dermatitis, particularly of toes or feet, which is commonly called “ground itch,” “foot itch,” or “dew itch.” This is most frequent between the toes or on the inner side of the sole of the foot. The irritation is due to the penetration into the cutaneous tissues of the hookworm larvae. The itching is intense and secondary infections often occur as the result of scratching. Vesicles appear about the second day and are often ruptured by the scratching with a resulting pustular or impetiginous conditions. The skin and hair generally are dry.

As a rule the temperature is normal throughout the course of an
uncomplicated case of hookworm disease. During the first week or so
following a heavy infection there may be pulmonary manifestations
when the larvae are migrating by way of the lungs.

In the diagnosis of a case Stiles attaches much importance to a tallow-yellow color of the alae of the nose and the forehead, as well as to the eye characteristics which are like those seen in the eye of a fish or that of an intoxicated person.

He also notes that the pupil tends to dilate instead of to contract
when the patient looks at a bright light. It has seemed to me that
the condition is rather one of hippus. In severe cases retinal
haemorrhages may occur. There may be night blindness. Ascites may
be present in advanced cases.

Symptoms in Detail

_Skin Manifestations._—The dermatitis following the penetration of
the larvae is most often about the toes or inner side of the sole
of the foot. The skin is very dry and often a pale earthy color.
A tallow-yellow tinting of the alae of the nose may be observed.
The hair is dry and scanty or absent in pubic and beard regions.
Oedema, especially of ankles or feet, is common.

_Circulatory and Respiratory Systems._—Palpitation of the heart is
early and marked. Functional murmurs are frequent in the advanced
stages. Pulsation of the neck veins is also common. The pulse
rate averages about 110 and the blood pressure is low. There is
frequently some right side dilatation of the heart. A high pulse
pressure is common in severe cases. Shortness of breath on slight
exertion is the most common respiratory symptom. There are at times
cough and bronchitis, probably induced by the irritation of the
larvae in the pulmonary alveoli.

_Digestive System._—Epigastric tenderness going to the right
is very characteristic. The stomach is often dilated and the
gastric juice hyperacid. As the anaemia increases the acidity
diminishes. It has been suggested that the desire to neutralize
this acidity with an alkali is the explanation of the desire for
alkali-containing earth on the part of “dirt eaters.”

Patients often are pot-bellied. Constipation is rather a common
feature and the stools very rarely show macroscopic blood.

_Nervous System._—Hookworm patients are not only physically
tired but, as well, mentally tired. The infection in children
leads to a backward mental state. Patients have very little
energy or initiative and are often considered stupid and lazy.
Hypochondriasis is at times noted and some severe cases become
melancholic.

_The Blood._—The red cell count averages in marked cases 2,500,000
to 3,000,000 red cells per cu. mm. The Hb. percentage is down in
such cases to between 30 and 50. The color index is well below
1, except in certain rare cases, when the color index is that of
pernicious anaemia, being above 1. These latter cases are very
resistant to treatment and often show very few infecting worms
notwithstanding the severity of the symptoms.

There is at times a moderate leucocytosis but as a rule the white
count is approximately normal.

Eosinophilia is quite characteristic and usually ranges from 15 to
35% of the leucocytes. Eosinophilia tends to disappear as the cases
become advanced.

The spleen and liver very rarely give rise to any symptoms and
while albuminuria is rather common in advanced cases with oedema
about the feet, yet casts are but rarely found.

DIAGNOSIS

=Clinical Diagnosis.=—The diseases with which it is most likely to be confused are beriberi, chronic nephritis and malarial cachexia. Stiles notes that heavy _Ascaris_ infections may give rather similar symptoms.

The signs of a multiple neuritis should differentiate beriberi, and
the presence of casts or high blood pressure, chronic nephritis.
Recently, there has been a great deal written about the danger of
confusing hookworm disease and malarial cachexia, the statement
being often made that splenic enlargement is a feature of
ancylostomiasis. Most authorities, however, state that the spleen
of ancylostomiasis is not enlarged, this point being of diagnostic
value in differentiating it from malaria and kala-azar.

=Laboratory Diagnosis.=—As a matter of fact the diagnosis is almost invariably made by finding hookworm ova in the faeces. The eggs are oval and thin-shelled with a wide, clear, glassy zone separating the more or less segmented, granular central portion from the shell.

Formed stools are more satisfactory for examination than the
liquid ones resulting from a dose of salts. Put about 2 drops of
water or 1% trikresol solution in the centre of a glass slide and
emulsify in it as much of the faeces as is held by the spatulate
end of a wooden toothpick. A small piece of wood or a match stick
will answer. These preparations can be readily examined without a
cover-glass, using a ⅔ inch objective, with a 1-inch ocular.

Cultural methods give a higher percentage of success than looking
for ova in the stools. Put a pile of 2 inch filter papers in the
center of a Petri dish. Fill the dish with water to the level of
the paper island. Smear a thick layer of faeces on the paper. The
larvae hatch out and can be found by centrifuging the water.

It is usually stated that about 500 worms must be present for
several months to produce symptoms. Grassi has thought that the
presence of 150 eggs in 0.01 gm. faeces indicates the presence of
1,000 worms, of which 25% would be males.

There may be as many as 4,000,000 eggs in a stool. Bass has
proposed the following method for the examination of faeces for
ova: The faeces, which have been made fluid, should be centrifuged
and the supernatant fluid containing vegetable débris poured off.
The sediment contains hookworm eggs. Then pour on sediment a
calcium chloride solution of sp. gr. 1.050. Again centrifuge and
decant. Next add calcium chloride solution of a sp. gr. of 1.250
and centrifuge. This brings to the surface the hookworm eggs which
may be pipetted off. As a rule, the finding of hookworm eggs is
very easy without such a technique.

Recently we have been using Barber’s technique. Emulsify the faeces
in equal parts of glycerine and saturated salt solution on a slide.
The eggs rise to the surface and are easily discovered with the
⅔-inch objective. As a centrifuge method, Barber emulsifies faeces
in this same mixture which brings the eggs to the surface. A wisp
of cotton is placed on the surface and 3 or 4 drops of melted
agar dropped on the cotton. The disc of agar is removed with the
cotton, deposited on a slide and examined for entangled eggs. With
operculated eggs this method does not seem to be satisfactory as
the salt solution loosens the operculum and floods the contents
of the shell,—thus altering the specific gravity of the egg and
preventing flotation.

_Lane Levitation Method._—Clayton Lane recommends a technique
which he designates as the levitation method. In this procedure the
concentrated sediment of a centrifuged specimen is transferred to a
glass slide, where it is mixed with one cc. of water. The slide is
allowed to stand for five minutes and is then immersed in water and
manipulated until all coarse matter has floated free. The hookworm
ova stick firmly to the slide and are not washed away. Lane reports
that on an average this method results in a ten-fold concentration
of ova.

In certain cases, where a microscope is not available, the
diagnosis may be made by finding the worms in the stool following a
thymol treatment.

Whyte has recommended the phenolphthalein test for occult blood as
of value in determining the cure of ancylostomiasis. This test is
so delicate that the least trace of blood from the mucosal lesion
will be detected.

The presence of eosinophilia is of great assistance in diagnosis but it should be remembered that not rarely severe cases of the disease fail to show any excess of eosinophiles.

Charcot-Leyden crystals are often present in hookworm stools.

PROGNOSIS

The disease is more serious in children than in adults, on account of its interfering with physical and mental development. The dark races do not seem to suffer as much as the white ones. Treatment is usually most successful, but in those who are debilitated by other diseases or, in those in whom the disease has assumed a pernicious anaemia tendency, the outlook is not good.

The presence of eosinophilia is of good prognostic significance
as the absence of eosinophiles indicates an exhaustion of the
haemopoietic system.

The disease shortens the life of the people in an infected district
and makes them readily fall victims to intercurrent diseases.
Various statistics give the mortality as from less than one-half of
1% to figures approximating 7%.

PROPHYLAXIS AND TREATMENT

=Prophylaxis.=—The first measure is to diagnose infections in carriers and to insist upon the treatment of such persons. The proper disposal of the fecal material from hookworm patients is the objective point in prophylaxis.

The use of some type of properly constructed privy is essential as
there is nothing more favorable to the development of the hookworm
larvae from eggs to infecting stage than the practice of defecating
on the ground where conditions of porous, sandy soil, shade and
moisture exist. Later on, such a spot teems with infecting larvae
and the person stepping there with bare feet is almost sure to
become infected. For this reason the wearing of shoes is an
important prophylactic measure. At the same time shoes are not a
sure protection, as Ashford has noted infections in soldiers who
wore good shoes. The fecal material, collected in a pail or tub,
should preferably be burned or boiled. Otherwise it should be
buried not less than 300 feet from the water supply and down hill
from the same.

The best method is to use some septic tank process as the anaerobic processes of fermentation destroy the eggs.

The use of an amount of compound cresol solution equaling the fecal
mass, plus urine, is of value.

Hookworm disease tends to disappear in towns or cities where there
is an efficient sewerage system.

Hookworm disease is one of the most conspicuous examples of soil pollution disease.

Some authors think _Ancylostoma_ more difficult to expel than
_Necator_.

=Treatment.=—The drugs best known in treatment are thymol and chenopodium but carbon tetrachloride offers the greatest promise.

_The Thymol Treatment._—Bozzolo introduced this drug in the treatment of hookworm disease in 1879. Thymol has an aromatic, thyme-like odor and a pungent taste and, while soluble in about an equal amount of alcohol, is only soluble in water in the proportion of 1 to 1100.

It is usual to prescribe the drug in 5-grain capsules or preferably
in cachets, one part of thymol being triturated with an equal
amount of sugar of milk. If the cachet is moistened with a little
water it may be swallowed like a raw oyster.

Stiles prefers giving the treatment on Sunday so that the working
days of the patient may not be lessened. By giving the patient
bicarbonate of soda for a few days before the treatment it is
thought that the mucus lining of the jejunum is cleared away so
that the worms are more readily affected by the drug. At any rate
one should give about 1 or 2 ounces of a 50% solution of Epsom
salts on Saturday evening. Sodium sulphate is preferred by some.

The following morning at 6 A.M. the patient takes one-half the dose
of thymol proper for his age and at 8 A.M. he takes the remaining
half of the dose. At 10 A.M. he takes another dose of Epsom
salts. The reason for dividing the dose of thymol is that should
untoward symptoms occur after the first portion of the dose we do
not give the second. Stiles now prefers to divide his dose into
three portions, one to be given at 6 A.M., one at 7 A.M. and the
remaining third portion at 8 A.M., followed by salts at 10 A.M. The
patient should lie on the right side while taking the treatment to
facilitate the passage of the drug from the often dilated stomach.

The patient should remain in bed until 12 o’clock when he may take
some coffee, without milk, and crackers.

Patients must be warned to avoid anything containing fats or alcohol while undergoing treatment as fats and alcohol dissolve the thymol and tend to cause poisoning. Under no circumstances should castor oil be used. People are apt to forget that butter, milk, etc., contain the dangerous fats.

Seidell has shown that about one-third of the thymol dosage is
excreted in the urine and very little by faeces. This shows
absorption of the drug. It is thought some of the drug may be
excreted by the lungs. Congestion of the lungs has been reported in
fatal cases of thymol poisoning.

Mild symptoms of poisoning are burning in the pit of the stomach
and tingling sensations of the body. More severe symptoms are
those associated with cardiac weakness and respiratory distress.
Coffee and strychnine are the usual remedies for thymol poisoning.
Inhalation, but not swallowing, of aromatic spirits of ammonia is
often of value.

The thymol dosage recommended according to the age, or rather the
apparent age of the patient, is:

Under 5 years old 7½ grains.
From 5 to 9 years old 15 grains.
From 10 to 14 years old 30 grains.
From 15 to 19 years old 45 grains.
From 20 to 59 years old 60 grains.
Above 60 years old 30 to 45 grains.

Total dose to be divided into 2 or 3 portions. The patient is
allowed to eat only a light luncheon and supper the day of the
treatment but the next day he may resume his regular meals.

As a rule most of the worms expelled by the treatment will
have been passed by night of the day of treatment, although an
occasional one may be passed for four or five days.

In from 25 to 50% of cases all the worms may be expelled in one treatment but it is usually necessary to give as many as 3 treatments, one on each of three Sundays.

_Thymol and Beta-naphthol._—Nicol in a comparison of the efficacy
of various drugs, noted that thymol in 90-grain doses, taken in
3 portions of 30 grains each, at 6, 8, and 10 A.M. expelled 98%
of the worms at the first treatment and the remaining worms at
the second treatment a week later. With this rather large dose he
frequently observed a tendency to syncope. He used Epsom salts as a
purgative.

On the other hand, while using 60 grains of beta-naphthol, given in
two portions at 6 and 8 A.M., followed by salts, 86% of the worms
were expelled at the first treatment and 14% with the second one.
He did not observe any bad effects from beta-naphthol.

The great objection to beta-naphthol is that it is a renal irritant
and may damage a kidney already diseased.

Nicol found the treatment with eucalyptus oil, 2 cc., chloroform,
3 cc. and castor oil, 30 cc. vastly inferior in anthelminthic
effect to the other two treatments and liable to cause severe
manifestations of nausea and syncope.

It is better to divide the dose as just stated into two portions,
the second half to be given about one-half hour after the first
portion. This reduces the danger from the chloroform.

Schüffner tried male fern and only obtained 7 hookworms while the
next day, using thymol, 1253 hookworms were expelled. He notes that
thymol is dangerous when administered to patients with acute or
subacute dysentery.

In Brazil a tabloid of 5 grains beta-naphthol combined with 1
grain of phenolphthalein has been generally employed. Using
phenolphthalein in this way enables them to dispense with purgation.

_Oil of Chenopodium Treatment._—As the result of comparing the relative efficiency of thymol and oil of chenopodium the International Health Board Commission reported in favor of oil of chenopodium. In only 7.6% of the cases treated with chenopodium was there failure to eradicate the parasites while there was noted 23.6% of failures with thymol. The dose of oil of chenopodium recommended was 1.5 cc. given in three divided doses of O.5 cc. at 7, 8, and 9 o’clock in the morning. Two such treatments will remove 99% of worms present in a case. The Commission found the oil more efficient than an emulsion of the oil.

The low diet and preliminary dose of salts, as noted under thymol
treatment, are to be recommended although the commission found
various purges to have little effect on the results of treatment.
At 11 o’clock give a purgative dose of magnesium sulphate.

The maximum dose of oil of chenopodium is usually given as 3 cc.
but a number of deaths have followed the administration of doses of
from 2 to 3 cc., so that it is better to keep within 1.5 cc.

After effects of treatment, such as dizziness, depression, unsteady
gait, partial loss of consciousness, tingling of hands and feet,
burning sensation in the epigastric region and nausea are more
frequent with chenopodium than following thymol. The toxic symptoms
may be greatly delayed and even be postponed for a day or so. A
large dose of castor oil seems to be the most important measure
in treating a case of chenopodium poisoning. The same methods of
stimulation as noted under thymol poisoning are also indicated.

Kantor has treated a large number of cases with oil of chenopodium
administered through the duodenal tube. After the bucket had passed
the pylorus he introduced into the duodenum about 2 cc. of oil of
chenopodium and followed this in six minutes with two (2) ounces
of a warm saturated solution of magnesium sulphate. The tube is
withdrawn after introducing the salts. Several copious watery
stools follow in a short time.

_Carbon tetrachloride_ in a dose of 3 cc. administered in hard
gelatine capsules, is recommended by Hall for the removal of
hookworms and ascarids. The drug is cheaper, more effective, and,
when chemically pure, safer than thymol or chenopodium. It does
not depress unstriated musculature or lessen peristalsis, thus
eliminating the use of purgatives, which is an item of expense in
extensive hookworm campaigns. The drug is of no value in treatment
of tapeworms and is as unreliable as other anthelminthics for the
removal of whip-worms.

There is a rapidly growing mass of reports concerning the clinical use of carbon tetrachloride, all of which agree in confirming experimental observations regarding its effectiveness, and indicate that a standard dosage as high as 10 to 12 cc. may be safely employed.

After expelling the worms it is advisable to give the patient a tonic containing iron or arsenic. In those cases with a tendency to pernicious anaemia the arsenic treatment is better than that with iron.

In the treatment of ground itch the usual application is a zinc
oxide ointment containing 10 grains of salicylic acid to the ounce.

Barlow recommends a 3% salicylic acid solution in alcohol.