George Dock.

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'^If the patient is directed to stare intently into the
observer's eyes, there will be noticed a symptom which it
is difficult to describe, but which I have found more constant
than almost any other noticed — namely, after a moment,
the length of time apparently varying slightly according
to the degree of the disease, the pupils dilate and the
patient's eyes assume a dull, blank, almost fish-like or
cadaveric stare, very similar to that noticed in cases of
extreme alcoholic intoxication." Ashford and King found


dilatability of the pupil noticeable in their Porto Rico cases.
AVe have often noticed that the pupil dilates readily, and
usually remains wide, even in the presence of considerable
light, but this is a common symptom of all severe anemias.

Nervous system. — Nervous and mental symptoms of
various kinds are not infrequently present in hookworm
patients, and sometimes cause great diagnostic difficulty.
There are few, if any, nervous symptoms, however, that can
not be ascribed to the anemia. There is a general benumb-
ing of the mental faculties in acute cases, but the chronic
hookworm child is generally well up in mentality with
others of his size and vigor, but usually not equal to those
of his age. In the acute and very severe form the disease
produces often melancholia, hypochondriasis, and a careless
expression. Insomnia and night terrors are very common,
due, no doubt, to feeding and moving about by the worms,
which the nervous system feels more when the patient is
perfectly quiet, as in sleep, than when active. Somnolence,
on the other hand, often occurs, and the patient keeps awake
in day time with difficulty. Lack of ambition is noticeable,
and has given rise to the idea that the patient is laz}^
Hookworm patients do not work as much or as well as those
not infected, but it is because they are sick and not because
they are lazy. In the last few years a great deal has been
said in the newspapers jokingly about the "lazy disease,"
and, if the same amount of publication had been devoted to
dissemination of knowledge of the sources and the preven-
tion of the disease, there is no doubt that it would be less
prevalent today.

Signorelli (1909) reports some interesting cases. In one,
a boy of 10, with mild anemia, had a meningeal syndrome,
with headache, vomiting, neuromuscular hyperesthesia,
cervical rigidity, Kernig's sign, etc., cured by thymol. A
girl of 17, with neuralgia, especially crural, anesthesia, and


paresthesia, was quickly cured by thymol after the blood
count showed 30 percent of eosinophiles and the anamnesis
revealed previous residence in Brazil. In another case, a
woman of 23, vasomotor disturbances and epileptiform con-
vulsions were equally amenable to specific treatment with
thymol. Signorelli emphasizes the tendency of hookworm,
like the malarial parasite, to cause vasomotor abnormalities.

Austregesilo and Gotuzzo (Eio de Janeiro, 1909) call at-
tention to the possibility of severe psychic alterations in
ankylostomiasis. They report the case of a man of 26, free
from history of alcohol or syphilis, who became apathetic
and melancholic, later complained of severe and continued
pain in head and abdomen, and of dyspnea and fatigue on
exertion, and finally had delusions of poisoning. Severe
anemia with eosinophilia led to thymol treatment and to
complete recovery. In another case there were many evi-
dences of psychic degeneration, with loss of memory, re-
ligious hallucinations, and delirium of grandeur. Anemia
and 18 percent of eosinophiles suggested thymol treatment,
and complete recovery followed. In another, with hemo-
globin 35 percent, red blood corpuscles 3,100,000, and eosino-
philes 16, there was complete loss of sense of time and place.
Later, the condition described by Oppenheim as ''Witzel-
sucht" developed. The patient was ironic and sarcastic,
ridiculed everything and everybody. Improvement of the
ankylostomiasis coincided with that of the mental condition,
and finally both were cured.

MacDonald, in Australia (1908), has seen various perver-
sions besides dirt eating among hookworm patients, espe-
cially children, mentioning disobedience, profanity, lying,
stealing, drinking, forging, and sexual perversions. These,
of course, are not rare manifestations without hookworm,
but the important thing is that in the cases reported re-
covery followed cure of the hookworms. The youngest


patient was only 8 months old. Allan has called attention
to the frequent association of neurasthenia and hookworm,
as might be expected. It would be interesting to make
observations on the psychic reactions of such cases of
various dfegrees of severity. Perhaps some of the exuber-
ant lawlessness of hookworm regions may be due to the lack
of control caused by the infection.

Sodre, and also Austregesilo and Gotuzzo, suggest that
the parorexia of hookworm infection is an evidence of the
altered mental condition, rather than the direct result of the
disease in the intestinal tract.

Finally, we want to emphasize the fact that hookworm
disease is likely to have associated with it other diseases,
and the symptoms of each be altered by the other. All
symptoms presented by a hookworm patient must not neces-
sarily be attributed to this disease. On the other hand, a
part of the symptoms in cases having other diseases may be
due to hookworm disease.



"The secret of the diagnosis of ankylostomiasis, like that
of many other diseases, is to suspect its presence."

An absolutely certain diagnosis of hookworm infection
can not be made without finding the eggs or worms in the
feces. It is possible, however, to diagnose it symptomatic-
ally with reasonable certainty in most cases showing well-
marked symptoms, provided this disease is kept in mind.
The combination of the characteristic anemia associated
with underdevelopment, weakness, dilated heart, and a
history of ground itch is not likely to be confounded with
anything else. We can not emphasize too forcibly the im-
portance of this history of ground itch, or ''toe itch," with-
in the preceding years. In all patients from warm climates
presenting anemia and impaired development without
obvious cause this should be inquired for. Whenever a
history of toe itch is obtained, nothing short of thorough
examination of the feces for eggs permits elimination of
hookworm from the diagnosis.

A history of ground itch, or hookworm disease, aifecting
other members of an individual's family, or those living on
the same plantation or in the same surroundings, usually
indicates that the patient is also infected, though he never
had ground itch himself.

The history of going barefoot during the summer in a
locality known to be infected usually means that the pa-
tient is infected, though he has not had a definite attack of



ground itcli. So few larvae may enter the skin at a time as
not to produce recognizable or characteristic lesions.

In infected localities, as Tenholt found among miners
in infected mines, and Stiles in his journeys through the
southern "United States, the diagnosis of hookworm disease
can often be made by inspection, and will turn out to be cor-
rect in the majority of cases. In such places, where time
for examination is short, treatment may be carried out on
the ground of the symptomatic diagnosis and the accurate
diagnosis made by examining the stools for worms after-
ward. The diagnosis of cases can be made almost as ac-
curately from the great imiDrovement after thymol treat-
ment. This sort of diagnosis, however, can not be looked
on as satisfactory or scientific, nor will it discover the im-
portant class of hookworm carriers.

Though the diagnosis may be indicated by the history and
symptoms present in all well-marked cases of hookworm
disease, these fail in a large number of cases that have not
obvious symptoms, either because of small number of
worms, or because of more or less immunity to the effects
of the worms. The most practical and satisfactory way
of arriving at a certain diagnosis is by examining the feces
for ova of the parasite. These are characteristic, easily
recognized, and, when worms are present in sufficient num-
bers and under such conditions as to cause symptoms, are so
easily found that the diagnosis becomes one of the most
simple procedures in the practice of medicine, provided one
is equipped with a microscope and proper knowledge and
experience, which can be easily acquired. The microscopic
examination of feces is of so much importance in diagnosis
that we believe a complete description of every detail is
warranted, including descriptions of the many things likely
to be mistaken for or confused with hookworm eggs.


Obtaining- Specimens for Examination.

The quantity of feces needed for a microscoiDic examina-
tion, even when the most comprehensive examination de-
scribed on ]jages 171 to 177 is to be made, need not exceed
two or three drams at most. Unless instructed on this point,
the patient will often bring or send large quantities or the
whole stool in fruit jars, large pickle jars, etc. Large ves-
sels of feces are much more exposed to accidents — such as
breaking or spilling, especially when the feces are liquid —
than smaller ones. More malodorous gases are given off
from a large amount of feces than from, say, one-twentieth
of this quantity. The opening ujd and handling of a small
quantity of feces in the laboratory or office is not nearly so
unpleasant as handling a much larger quantity. It is not
sufficient to tell the patient to bring only a small quantity.
This point must be impressed on him when requesting him
to bring the specimen. He should be told to bring only a
small quantity of the actual feces, and the physician should
make this more certain by furnishing him with a suitable
receptacle in which to bring or send the specimen, and when
it is given him to explain that he wants only a small quan-
tity in it and not to fill it full. Vaseline bottles, two-dram
quinine bottles, or other low form wide-mouth bottles serve
the purpose well. One who expects to have many specimens
of feces brought to him by his patients should provide him-
self with a proper supply of two-ounce wide-mouth bottles
with corks. They are also appropriate for sj^utum bottles.
These should never be used a second time. Wide-mouth
bottles also have a great advantage in permitting feces to
be put in and taken out of them. Moreover, when feces are
put in a narrow-mouth bottle, they usually lodge partly in
the neck, and, after the stopper is put in, gases form which
often blow out the cork and feces, soiling anything or any-


body near by. When bottles are entirely filled with feces,
especially if liquid, the stopper is very likely to be blown
out when the package is unwrapped, if not before. If only
partly filled, this is not so likely to occur.

, Kind of Feces to be Examined.

Any kind of a stool will do for examination, but there are
reasons for preferring the formed feces instead of liquid
material. These reasons are that the preparation on the
microscope slide can be more satisfactorily made with
formed feces; that liquid feces are more odorous and
more likely to get out of the bottle accidentally; and
that eggs sometimes tend to settle to the bottom of
a liquid, and greater care is therefore necessary in mak-
ing the preparation on the slide; and that, if the speci-
men is very liquid, eggs are likely to precipitate and stick
to the bottom and sides of the bottle, and be missed when
only a few eggs are present, in spite of considerable agita-
tion. Pepper has called attention to the peculiarity pos-
sessed by hookworm eggs of sticking to the slide after they
have once settled in a slide preparation. One who wishes to
thoroughly familiarize himself with examination of stools
for hookworm eggs should try this for himself. Place on a
slide some sediment from centrifuging, described on page
173, containing hookworm eggs. Dip or invert the slide
in a beaker of water after allowing the material to settle
a few minutes. Now examine the slide under the micro-
scope, and the eggs will be found to have stuck to tile slide
even after considerable agitation, though everything else
came off.

Making- the Preparation for Microscopic Examination.

For the examination of feces the ordinary 3-inch slides
are too small for the most satisfactory manipulation. We


prefer 2x3-mc]i slides, or even larger. Photographic nega-
tive glasses 31/4x31/4, 3^/4x41^, or 4x5 are all very convenient,
and usually easy to get. The ordinary 1x3 slides, however,
serve the purpose well, especially if a mechanical stage is

Put in the center of a slide one to three drops of water.

Fig-. 45. Diluted feces on slide, ready for microscopic examination.

and with a toothpick take up a quantity of feces about the
size of a match head. Stir this into the water until it is
about as cloudy as can be examined well with the micro-
scope, spreading out the diluted feces properly over the
slide at the same time. The diluted feces should not come
quite to the edge or ends of the slide at any point, as they


would then easily run off on the hands, microscope, etc.
The preparation should cover at least one-half the area of
the slide if the ordinary 1x3 slide is used. (Fig. 45.) The
thickness of the mixture must be learned by experience, but
it is desirable to have it dilute enough to allow a good light
to be had and a clear outline of the material on the slide. A
preparation that allows ordinary print to be read through
with the unaided eye is usually not too thick. It is not
necessary to continue stirring the feces off the pick after the
mixture becomes of the proper consistency. If properly
manipulated so as to rub off the feces gradually, it is easy
to stop at any point desired and to throw away any excess of
feces with the j)ick. Ordinary toothpicks are the best
things we have ever seen for making such preparations.
They have been used for a long time for this and similar
purposes by many laboratory workers. They should be of
good quality and have one thin flat end. The same pick
should never be used for examining another specimen on ac-
count of the possibility of carrying eggs from one to the
other. Matches or other such pieces of wood serve tlie pur-
pose also, but not so well. A convenient way to dispose of
the soiled picks is to burn the used end over a flame, or they
may be dropped into the bottle, which is then stoppered so
as to avoid contamination and infection.

Use of Cover Glasses Unnecessary.

It is unnecessary to use cover glasses in examining feces
for hookworm or most other parasite eggs. With the mag-
nification generally used they are absolutely unnecessary.
It is usually necessary to examine preparations larger than
the regular cover glasses and sometimes several of them.
If it is desired to study a specimen with high powers for
some special purpose, it is easy to place a cover glass over
the part to be examined, and press it down gently to thin it


out. Cover glasses are also necessary if a great deal of
time is to be spent in examining a given slide, to prevent the
preparation drying out so rapidly.

Examine Only Wet Preparations.

The preparation is to be examined wet. As soon as it
dries it is useless, and, if this happens before an examina-
tion is completed, more water is to be added, or another
preparation should be made. A properly made preparation
can be entirely gone over with the low power lens before it
dries out appreciably. If spread out too thin, it will dry
much more rapidly. Most of the solid particles, including
eggs, if present, settle on the surface of the slide soon
after it is prepared, and are then found about in the same
level or focus, so that the thicker the layer, provided it does
not prevent seeing through it, the more concentrated will be
the objects on the surface.


The low power of any of the commonly used microscopes
is to be employed. The 2/3 objective and 1-inch eyepiece,
or the 16-millimeter objective and corresponding eyepiece,
give the proper magnification of about 100 diameters.
Higher magnification is undesirable for general work be-
cause the field is correspondingly reduced, and therefore it
takes much longer to look over a preparation.

Time Required and Number of Slides to be Examined.

The time required to examine for eggs varies with the ex-
perience and speed of the examiner, the number of eggs
present, the thickness and size of the preparation, and
whether there are many particles resembling eggs, requir-
ing close observation to differentiate them. If many eggs


are present, the diagnosis may often be made on the first
field examined, but to stop after finding a few hookworm
eggs is not good practice. The examination should be con-
tinued to find, if present, eggs of other parasites which are
likely to ^e present in small numbers, and to get some idea
of the number. When less than ten female worms are pres-
ent, there may be an average of less than one egg to a slide.
It is estimated that one actively laying female produces
two thousand to three thousand eggs in twenty -four hours,
but many of the worms lay much fewer eggs and a few old
ones lay none.

We recently had each man of several groups of five medi-
cal students examine five or more slides of one hundred dif-
ferent specimens of feces, twenty-nine of which finally
showed mild hookworm infection. The remainder, seventy-
one, were negative. Several instances occurred in which
only one or two men of the group found one or two eggs in
a particular specimen. These men had been thoroughly in-
structed and practiced in the recognition of hookworm eggs,
and it is believed were not likely to overlook them. Eggs
were found in only twenty-three specimens from this exami-
nation of twenty-five slides of each. The negative speci-
mens were now examined after being carefully washed and
centrif uged, and six found to contain eggs. In this instance
examination of twenty-five slides failed to demonstrate eggs
in 20 percent of the cases in which they were present.
These were the ordinary 1x3 microscope slides, and the
specimens were from adults who had very few worms — not
enough to produce any recognizable symptoms, except in
one or two instances. Most of them had not been rein-
fected in many years, and their worms certainly were not
laying as prolifically as younger worms do.

Another group of ten men were first well drilled on the
diagnosis of worm eggs and then set to work to examine


oue hundred and thirty-six specimens of feces that showed
on final examination fifty-eight infected, as follows: six
hookworm, thirty-two trichocephalus, eight tenia nana,
twelve oxyuris. One to five slides were examined — an
average of two or three. Thirty-one, or 53 percent, of the
specimens containing eggs were diagnosed negative by this
examination. They were mild infections, and all these
worms other than hookworms lay comparatively few eggs,
as is well known. These figures show that examining two
or three, or even twenty-five, ordinary slide preparations
is not sufficient to discover eggs every time when very few
are present. It is necessary to examine at least six to ten
slides before a practical negative diagnosis can be made,
but, if one hundred or more worms are present, eggs can be
found in every slide, except under rare conditions. The
number of worms in many well-marked or severe cases is
from one thousand to four thousand, and eggs, often several,
can be found in almost every microscope field. We can look
over thoroughly an ordinary slide in two to four minutes.
We have seen comparative beginners become able, with a
few days of practice, to examine well one slide in six to ten


The amount of light used should be that giving the best
detail to the small particles in the preparation. On an
ordinarily bright day, or with artificial light, the maximum
light available when using any standard microscope will be
entirely too strong, and must be reduced by partly closing
the iris diaphragm under the Abbe condenser. The light
is increased or decreased with this diaphragm after the re-
flector has been adjusted so as to reflect directly all the light
falling upon it. The light should be such as permits eggs,
when present, to be seen well in detail. The outline of the


yolk and shell should be distinct, and the clear albumen
space should be well shown. With too bright a light the
whole egg is blurred and indistinct.

Method of Going Over the Slide.

If a mechanical stage is used, it is a good plan to begin
at one side of a preparation and to move the slide systemat-
ically from end to end, moving back or forth the width of a
field every time the end is reached until the entire slide has
been gone over. With a large slide, or if no mechanical
stage is used, the slide should be moved in the same manner
with the fingers. With practice and with low power, this
can be readily done.

Description of Eggs.

The ova of uncinaria Americana are ellipsoid, fifty-four
to seventy-two microns long by thirty-six to forty microns
broad, in some cases partially segmented in utero. The
ova of ankylostoma duodenale are ellipsoid, fifty-six to
sixty-one microns by thirty-four to thirty-eight microns,
laid in segmentation. The two varieties have practically
the same general appearance, and can not be differentiated
except by careful measurement. Uncinaria Americana
eggs are said to be more pointed at the poles. (Looss.)
Eggs may be seen lying flat, or they may be on end, in
which case they appear round. There are all variations
between these extremes, in which they appear shorter than
normal, due to their being seen in an oblique position on
the slide. With experience a mental picture of the size is
formed, which is all the guide to size necessary. Different
individuals see the size of things under the microscope dif-
ferently. To our eye, with a 1-inch eyepiece and a 2/3-inch
objective, hookworm eggs seem to be three-eighths to one-
half inch long by about one-fourth less than this in diam-


eter. The outline of the chitinoiis shell is smooth and regu-
lar, and shows as a narrow band. The regularity in out-
line of the shell often serves to differentiate them from the
capsular membrane enveloping the chlorophyl of many dif-
ferent varieties of vegetable cells. The yolk is made up of
fine granular dark gray material and contains a central
lighter area. When seen sufficiently early, the yolk is of
the same shape as the egg shell, and usually situated about
the same distance from it on all sides. There is a distinct
clear albumen space between the shell and yolk from one-
eighth to one-fifteenth as wide as the diameter of the egg.
Most of the eggs begin to segment before the feces are dis-
charged, and therefore those found in fresh material con-
tain two, four, or eight, or more segments. (Figs. 11, 13.)
In older stools embryos may be seen inside of the egg shell,
nearly ready to come out and moving around slowly in their
shell, which they nearly fill. (Fig. 11.) For a complete
description of the embryos and larvas see the chapter on

Number of Worms Indicated by Number of Eggs.

Leichtenstern has proposed to estimate the number of
worms present by the number of eggs found in the feces.
He divides the number of ova contained in one gram of
feces by the factor forty-seven. Grassi and Parona esti-
mate the number of eggs in one centigram of feces and cal-
culate the number of worms, assuming that one hundred
and fifty to one hundred and eighty eggs per centigram rep-
resent one thousand worms.

Ashford and King have called attention to the fact that
certain things may prevent the correct estimation of worms
by the eggs present. They well say that the worms cause
an increase of mucus at the site of their feeding ground,
and, as this mucus often comes off en masse and contains


most of the eggs, the actual feces would contain relatively
few. They sa^^ eggs are more difficult to find in diarrheal
stools for some reason or other, and in this connection we
mention the fact that the quantity of feces passed by differ-
ent individuals varies greatly with the size and age, the

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Online LibraryGeorge DockHookworm disease; etiology, pathology, diagnosis, prognosis, prophylaxis, and treatment → online text (page 10 of 17)