H. D. (Hiram Dana) Walker.

The gape worm of fowls (Syngamus trachealis); the earthworm (Lumbricus terrestris), its intermediate host. Also, On the prevention of the disease in fowls called the gapes, which is caused by this parasite online

. (page 1 of 3)
Online LibraryH. D. (Hiram Dana) WalkerThe gape worm of fowls (Syngamus trachealis); the earthworm (Lumbricus terrestris), its intermediate host. Also, On the prevention of the disease in fowls called the gapes, which is caused by this parasite → online text (page 1 of 3)
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Gape Worm of Fowls

( Syngamus trachealis );

(Lumbricas terrestris),



On the Prevention of the Disease in

Fowls called the Gapes, which

is Caused by this Parasite.



=7= RY,

U [> ■




Gape Worm of Fowls

(Syngamus trachealis);


{Lumbricus terrestris),


On the Prevention of the Disease in Fowls

Called the Gapes, which is Caused

by this Parasite.

By H. D. WALKER, M. D.,



DR. H. D. WALKER, Franklinville, N. Y.,


J. Y. BICKNELL, Buffalo, N. Y.
189 7.



Fig. 1— Adult, male and female Syngamus, united (natural size and enlarged 12 diameters).
A, male; B, female, each showing the head, esophagus and intestine. In the female
may be seen the uterus and ovarian tubes filled with eggs. In the male, the seineniferous


Fig. 2.— Smallest pair of Syngami ever seen (enlarged 50 diameters). A, male; B, female.

Fig. 3.— Embryo of Syngamus removed from the earthworm and kept in the blood serum of
a calf, in an incubator, at 105° Fahr., between four and five days. About moulting the
second time after being placed in the serum. Embryo lying within the exuviae. See
structure of mouth of embryo, and also in the exuviae (enlarged 200 diameters).

Fig. 4.— Embryo of Syngamus removed from the earth worm and kept in the blood serum of
a calf, in an incubator, at 105° Fahr., for 24 hours. About moulting the first time after
being placed in the serum (enlarged 200 diameters).

Fig. 5.— Embryo of Syngamus removed from the lung of a chick fed earthworms containing
the embryos. This embryo had just entered the lung (enlarged 200 diameters).

/7„ 6.— Embryo of Syngamus removed from the intestinal canal of an earthworm (enlarged
200 diameters).

jJ7 ff- 7.— Embryo of Syngamus within the egg < enlarged 200 diameters).

Fig. 8.— Egg of Syngamus in the mulberry state (enlarged 2li0 diameters).

jr tc ,. <». — Perfect egg of Syngamus immediately after passing out of adult female (enlarged
200 diameters).

/,•,„_ id— Caudal pouch of male. Observe the eight principal ribs which are subdivided SO
there are eighteen divisions at the circumference, each extremity of which i> expanded
into a sucker. These suckers project through the broad margin of the pouch which is
closely applied around the vulva of the female, to which they enable it very firmly to
adhere. The posterior part of the circumference of the pouch is cut out and has no suck-
ers. Here is where the eggs pass out.



Fourteen years having- elapsed since I first commenced the
study of the gapes in fowls, it cannot be asserted that the con-
clusions now arrived at are hasty and have not stood the test
of time and mature consideration. My first paper on the sub-
ject was read before the Buffalo Microscopical Club, November
nth, 1884. In 1886 I published a paper in the Bulletin of the
Buffalo Society of Natural Sciences, Vol. V., No. 2. The pres-
ent publication is a revision of that paper, with extracts from
articles written for various journals, and additional matter here-
tofore unpublished in regard to the life history of the parasite
causing the gapes. The illustrations are from drawings made
by Mrs. Helen M. Judd from microscopic slides. I send forth
this small pamphlet with the earnest desire that science and the
poultry and game bird raisers throughout the world may be

benefitted thereby.

Franklinville, N. Y., November, 1897.


In the following pages we present the results of experiments
made for the purpose of determining the intermediate host of
the gape worm of fowls. We have endeavored at the same time
to trace out the life history of this parasite, in its various stages
from the egg to the perfect worm, also to devise means for the
prevention of the disease caused by it among fowls.

The object of undertaking the work was two-fold. First, it
was thought if its intermediate host could be discovered the
disease might be prevented to a great degree, and much good
result therefrom. Second, the love of original investigation and
a determination to work out the life history of this parasite,
which, although well known in its mature condition in the
trachea of fowls for about one hundred years, had thus far, in its
embryonic state in nature, remained unknown. The work has
been exceedingly difficult, for several reasons. When the inves-
tigation was begun, I knew nothing about Entozoa. Microscop-
ical work was also comparatively new. Living in a small vil-
lage, I had no public libraries to consult, and was dependent for
the literature of the Entozoa on a few books which I procured
during the investigation. My profession also left me little leisure,
and the most of this work has been done at such odd times as I
could spare from other duties. I wish here to express my thanks
to that eminent naturalist, the late Dr. Joseph Leidy, of Phila-
delphia, for many favors in inspecting my microscopic slides, and
for advice and encouragement in the work. Valuable, indeed,
were the services he rendered me. I am under obligations to
Lord Walsingham, of England, for books to aid in the investi-
gation. Friends in the Buffalo Microscopical Club, and neigh-
bors have also assisted me in various ways. I have freely con-
sulted Dr. T. Spencer Cobbold's work on "Parasites," also Pro-
fessor L. G. Neumann's treatise on "Parasites and Parasitic Dis-
eases of Domesticated Animals," and Dr. Pierre Megnin, "On
the Gapes Disease in Gallinaceous Birds." Finally, I trust these
pages will not be scanned with too critical an eye, for, doubtless,
imperfections will be found. I can only say that I have honestly
endeavored, according to the best of my ability, to place before
the reader the life history of one of the humblest of creatures, a
worm, but which, nevertheless, plays well its own part in this
world of animated nature.


The Animal Kingdom is divided into several sub-kingdoms.
One of these is called Worms (Vermes). This sub-kingdom is
separated into classes, one of which is named Round Worms
(Ncmatliclminths). Another division into orders is made, among
which are the Nematode Worms (Nematodes). This order con-
tains, among other genera, that of Syngamus, which is repre-
sented by two species, Syngamus bronchialis and Syngamus
trachcalis, the last of which is the subject of our present work.*

Another name for this worm is Sclcrostoma, or Strongylus
syngamus. Syngamus trachcalis is stated to have been found in
the trachea of the turkey, domestic fowl, pheasant, partridge,
black stork, magpie, hooded crow, green woodpecker and star-
ling. I have, myself, found it in the robin, and believe most if

not all worm-eating birds serve as a host for this parasite.

The first public record of the Gapes was made by Dr. Wiesen-
thall, Professor of Anatomy at Baltimore, Md. In a communica-
tion dated May 21st, < 1797, and published in the Medical and
Physical Journal in 1799, he says: "There is a disease prevalent
among the gallinaceous poultry in this country called the gapes,
which destroys eight-tenths of our fowls in many parts, and is
most prevalent among young turkeys and chickens bred upon
established farms. Chicks and poults, in a few days after they
are hatched, are frequently found to open wide their mouths
and gasp for breath, at the same time sneezing and attempting
to swallow. At first the affection is slight, but gradually becomes
more and more oppressive, and ultimately destroys; very few
recover; they languish, grow dispirited, droop and die. It is
generally known that these symptoms are occasioned by worms
in the trachea. I have seen the whole windpipe completely filled
with these worms, and have been astonished at the animal's being
capable of respiration under such circumstances." The above
is a truthful description of the disease as it prevails in this coun-
try to-day. In 1808, Mr. George Montagu gave an account to
the Wernerian Society of a species of Fasciola. which infests
the trachea of poultry, with a mode of cure. This led to its being
noticed in the systematic works of the day. Dr. Cobbold, from

•The aame of the genus Syngamus is derived from two Greet words, o » 0, with, together,

andy«uo«, marriage, and 1ms icl'ercnee In the peculiar union of the sexes.

whose work on parasites this brief history was taken, has made
some observations on this worm. In 1879, Lord Walsingham,
of England, offered a prize of two hundred and fifty dollars, to
be awarded by the Council of the Entomolpgical Society of Lon-
don, for the best essay, comprising a complete life history of
the parasite causing the gapes. Mr. Charles Black and Dr.
Pierre Megnin, a well-known French scientist, competed for the
prize. The latter received the award. The conclusions at which
he arrived in regard to the propagation of the disease are as fol-
lows: First, that birds pick up mature Syn garni filled with eggs,
which are coughed out by those having the disease, or the eggs
are taken in their food, or the embryos after they are hatched in
water, and they are developed within them to the perfect form.
Second, that no intermediate host, as perfect insects, larvae, mol-
lusks, or any other living agent, has any share in spreading the
disease. In a supplement to the above, after discovering a
nymph of Syngamus in the pulmonary tissue of a red partridge,
he says: "In the preceding memoir, written about twenty months
ago, we pointed out that the eggs ejected during the coughing
fits hatch in the water, and that the embryo, resembling an
anguillula, may live in this medium for many months, because
we have kept some alive almost a year, in a low temperature.
The birds are infected by drinking the water containing these
embryos. But how are they developed in the body of birds,
and in what way do they reach the trachea, where they are found
in the adult stage, fixed to the mucous membrane, like leeches,
the two sexes united in a permanent manner, and the females
crowded with eggs?" He closes the supplement as follows:
"This discovery of the nymph enables us to say that all the
developmental phases of Syngamus trachealis are now known.
The only two media which this parasite inhabits during its entire
existence are the water or moist earth during its embryonal con-
dition, and the respiratory organs of its victim during its nymphal
and its adult phase. It is developed without the aid of any other
medium than the water, corresponding in this respect to the im-
mense majority of verminous parasites." This, then, is the con-
clusion at which Dr. Megnin arrives, after five or six years' study
of the gapes in the various pheasantries of Central France, and
around Paris. Dr. Cobbold says, in his work on "Parasites,"
page 445: "A change of hosts is probably necessary, but in the
first instance they either enter the substance of fungi or other


vegetable matters, or they bury themselves in the soil a short
distance from the surface." In Lord Walsingham's preface to
the essay by Dr. Megnin, he says: "By Dr. Megnin's permis-
sion, his memoir is now published in a separate form, the sub-
ject of it being one which could not rightly be included amongst
the publications' of the Entomological Society, although at the
time of offering the prize I was led, by information gathered from
various sources, to think it possible that the larvae of some insect
acted the part of host to the embryonic form of Syngamus." Dr.
Joseph Leidy believed the embryos would be found in some in-
termediate host. The above comprised our knowledge on the
subject when this research was begun.


The present investigation was commenced during the summer
of 1883. Great numbers of young poultry dying of the gapes,
some of my neighbors applied to me for aid to arrest the disease.
Knowing very little about the gapes, but having heard it was
caused by worms in the trachea, I made a careful examination
of their windpipes, and found numbers of the worms attached
thereto by their sucker-like mouths. Never having studied the
Entozoa, and having no works on them, I sent a specimen to
Dr. Joseph Leidy, of Philadelphia, asking him its name, and
where I would find information on the subject. He kindly re-
plied, and referred me to Dr. Cobbold on "Parasites," and an
article by Dr. N. H. Paaren, in the American Entomologist, Vol.
2, page 149. I immediately procured these, and reading the ar-
ticles on that subject, could find nothing regarding its origin.
I therefore again addressed Dr. Leidy, asking him for the de-
sired information. On August 15th, 1883, I received his reply
as follows: "The source of the gape worm (Syngamus trachealis),
of chickens, has not been discovered. If you have an opportunity
of investigating and determining its origin, you may do much
service to science. It would be found only in the embryonic
or larval condition, in some intermediate host." I thought this
was not only a good field for microscopic examination, but also
one which, should I succeed in the work, would be productive
of much good. Therefore, I commenced an investigation of the
coops and their vicinity, where the chicks suffered must from the
gapes. About these I found three not improbable sources of the
disease: First, the common earth worm (I.iimbriats terrestrls) ;


second, the sow bug (Oniscus ascllus); third, the garden slug
Limax Havus). My attention was especially directed to one coop
where the chicks all had the gapes. This was placed on a grassy
plot, but close by its side was a small space of bare ground, a
few inches square. It seemed quite probable that here was the
place where they obtained the parasite, so I dug into it and found
it full of earthworms. I took some of these home and exam-
ined them with the microscope, as I did also Oniscus and Limax.
I found that both the slug and earthworm contained various
kinds of parasites in abundance. None were found in Oniscus.
To determine which one, if any of these, was the intermediate
host of Syngamus trachcalis, I procured some young chicks from
a neighborhood where no gapes existed, and fed each separately
to the chicks. In neither of the chicks fed with sow bugs or
slugs was any result produced, but the chick fed with earth-
worms developed symptoms of the gapes. To guard against
error, all the chicks were kept in a barn where they had no access
to the ground, and their food was cornmeal mixed with pure


Exp. i. On September 29th, 1883, at 8:30 a. m., a marked
chick, about one week old, was fed ten earthworms from the bare
spot of ground by the side of the coop where the chicks had
the gapes. The worms were carefully washed in water to re-
move all the dirt adhering to them, which might contain the
eggs or embryos of Syngamus. On October 6th, at 7:30 a. m.,
six days and twenty-three hours after the feeding, I observed the
first symptoms of the gapes. On October 7th, at 10:30 a. m.,
eight days and two hours after feeding the chick, and twenty-
seven hours after the first symptoms of the disease, I killed it and
found twenty-six gape worms. Of these worms, two only were
found in the trachea; they were at its upper part, and were the
largest. Ten or twelve of them were in the pharynx. The re-
mainder were in the esophagus, from its upper part half way
down to the crop. All these were united in pairs, except one
male and female.

Exp. 2. On October gth, at 8 a. m., another chick, a little
over two weeks old, was fed four earthworms from the same
place, with like precautions. At the same time of day on the
10th it was fed six worms. On the nth, 12th, 13th, 14th and


15th it was fed ten worms daily. At the same time from the first
feeding, a little less than seven days, it had the gapes. It was
killed in eight days and twelve gape worms found, all in the

Exp. 3. November 13th three chicks, two days old, were fed
earth worms from my garden, eight, nine and ten days, respect-
ively. No symptoms of the gapes were produced, but to deter-
mine positively, the one fed nine days was killed, and no gape
worms found. This experiment shows that all earthworms do
not contain the embryo of Syngamus. To confirm this, earth-
worms from the same place have been repeatedly examined with
the microscope, and none of the embryos found.

Exp. 4. Two mature Syngami were broken in pieces, so as
to free the eggs. They were then placed on the surface of a dish
filled with dirt, well moistened with water. After two weeks
some earthworms were placed in this dish and allowed to remain
ten days. Three of these were fed to a chick, which was care-
fully watched for two weeks. No symptoms of gapes were dis-
covered. Evidently the embryos had not obtained access to
the earthworms in sufficient numbers to produce the disease in

Exps. 5 and 6. On December 13th, two chicks, four weeks
and four days old, were each fed six earthworms from the infected
spot, with the same precautions as before. On the 14th, 15th
and 1 6th the feeding of six worms was repeated, making twenty-
four to each chick. On December 20th, about seven days, as
before, they had the first symptoms of the gapes. One was now
killed, and twenty-two Syngami were found. On December
24th, eleven days from the first feeding, the other was killed, and
sixteen f6und. All of them were united, and in the trachea.
None were found in the lungs, but it is probable they were there,
and want of experience in the search prevented their discovery.

Exps. 7, 8 and 9. On April 21st, 1884, fed three chicks, two
days old, each five worms from the same place where the others
were obtained. Repeated the feeding on April 22d, 23d, 24th,
25th, 26th and 27th. On April 28th, about seven days from the
first feeding, all had the gapes. One was now killed ami Syngami
found in the trachea, also three pairs in the lower part of the left
lung and one pair in the lower part of the right lung. Continued
to feed the two remaining chicks earthworms until May 5th, just
two weeks from the first feeding, when one was killed and the


lower part of the trachea found crowded with Syngami. One of
these measured seven-eighths of an inch in length, and two or
three others three-fourths of an inch. They contained fully de-
veloped eggs, as did also the excretions of the chick just before
it was killed. This proves that the embryo of Syngamus in the
earthworm is developed to maturity in two weeks from the time
it obtains entrance to the chick. The last chick was killed seven-
teen days from the first feeding, when in articulo mortis. In the
lungs of each of those killed at fourteen and seventeen days from
the first feeding, embryo Syngami were found in various stages
of development.

Exp. 10. On July 16th, fed a chick ten earthworms, and re-
peated the feeding for nine successive days. The gapes observed
on the seventh day, as, usual. On July 26th, ten days from the
first feeding, I killed this chick and found a large number of
Syngami in the trachea, and also the embryos in different stages
of growth in the lungs.

Exp. 11. In order to see if Dr. Megnin's theory was correct,
that the eggs would develop within the fowl, I fed a chick about
three weeks old, on July 29th, three perfect Syngami, containing
many thousands of eggs. This chick was carefully watched for
five weeks, and no symptoms of gapes observed. That this re-
sult is correct, we have additional proof in exp. 8, in which large
numbers of perfect eggs were found in the excretions of the
chick, on the fourteenth day after feeding earthworms containing
the embryos of the gape worm. I believe however, if the eggs
should in any manner be retained so as to hatch before they
passed into the proventriculus,* the gapes would be produced,
but think such a case must be very rare, and would be unlikely
to occur unless the embryos were fully developed in the egg be-
fore they were taken by the fowl.

Exp. 12. Three young robins (Turdus migratorius), in the
nest, were fed several infested earthworms each, daily for twelve
days. These earthworms were taken from the same place as
those given the chicks. No well marked symptoms of the gapes
were observed. Two of them were killed, and three or four gape
worms found in the trachea of each. A number were also found
in process of development in the lungs. These birds live almost
entirely on earthworms during a part of the year, and I wished

*The proventriculus is the first or glandular stomach where the gastric juice is secreted,
the gizzard being the muscular stomach where the food is triturated.


to know whether they would serve as a host for the parasite, and
thus be instrumental in spreading the disease from farm to farm.
The trachea of robins differs, in its size and anatomical structure,
from that of poultry, especially at its lower part, where the last
ring dilates and forms a second larynx. Syngami generally col-
lect from the lower part of the trachea to its middle, and the
gapes is simply the effort of the bird to obtain more air through
this passage, which is obstructed by these worms. It is evident,
therefore, that birds which have a larger trachea would harbor
a greater number of Syngami without suffering from the gapes.
We see this is the case in chicks after they are several weeks
old, for Syngami can often be seen in their windpipes by open-
ing their mouths and straightening out their necks. Several
worms can thus be seen in large chicks, with very little embar-
rassment to respiration. It is also not improbable that, although
the embryos may penetrate the esophagus, pass to the lungs and
thence to the trachea, the greater part may be coughed up and
swallowed before they are able to obtain a hold on its mucous
membrane. We know from an examination of chicks that very
many of them are thrown off in this way.

Exp. 13. On July 4th, at 5 p. m., fed a chick, about four
weeks old, a large number of Syngami, just hatched, by turning
the water containing them down its throat. On July nth, at 7
p. m., this chick commenced to have the cough or sneeze char-
acteristic of the gapes. July 12th, coughed much more. On
July 13th, at 9 a. m., eight days and sixteen hours after the feed-
ing, I killed this chick and found one single and twenty-nine
pairs of Syngami,

Exp. 14. On August 14th, at 7 p. m., fed a young robin, just
from the nest, a large number of embryo Syngami, hatched in
water, as in the preceding experiment. It was kept in a cage
hanging under a tree, and fed by the old bird. August 22d.
morning: Robin had some symptoms of the gapes, such as rapid
breathing, an occasional gape and shake of the head, and was
inclined to sit on its perch, instead of standing up, as usual.
August 23d: Breathed more rapidly, and evidently quite ill. Au-
gust 26th: Robin continued to grow weaker and breathed more
rapidly, and at times gaped, but the gaping was not as promi-
nent a symptom as in the case of chicks. The robin died the
morning of the 29th, the fifteenth day from the feeding. ( to
examination three fair sized Syngami were found in the trachea.


not enough to fill it up, so as to produce much gaping. The
rapid breathing, which was the most prominent symptom, was
readily accounted for by extensive deposits in both lungs, more
especially the right. The lower part of each lung was affected,
and the diseased condition doubtless resulted from the irritation
of the parasites.* Many other feeding experiments with chicks
have been made in different years since the above. 'All of them
thoroughly confirm 'the foregoing ones in every respect, and it
is deemed unnecessary to detail them here. Experiment 13
proves that the embryo of Syngamus does not have to pass
through an intermediate host to obtain any change in structure,
or increase in development, that the earthworm is simply a
bearer, in which it lives in its embryonic condition, and through
which it obtains access to its final host, the fowl. This chick
was kept in the barn and all other sources of the disease excluded,

1 3

Online LibraryH. D. (Hiram Dana) WalkerThe gape worm of fowls (Syngamus trachealis); the earthworm (Lumbricus terrestris), its intermediate host. Also, On the prevention of the disease in fowls called the gapes, which is caused by this parasite → online text (page 1 of 3)