_Read at the Meeting of the Ophthalmological Society on March 14th, 1895._
By D. ARGYLL ROBERTSON.
(With Plate VII.)
At a meeting of this Society on the 18th of October last I narrated the
case of a patient, Miss H⸺, affected with _Filaria loa_, and I exhibited
a male worm which I had removed from under the conjunctiva of her left
eye. I purpose now to give a short account of the further history of that
patient, and a description of a female _Filaria loa_ which I succeeded in
removing from her right upper eyelid.
After the removal of the filaria from under the conjunctiva, Miss H⸺
was not troubled with the sensations she associates with the presence
of a worm for a period of about six weeks, when again she experienced
a burrowing sensation at the back of her left eye. It affected her at
intervals, and especially when she was occupying a hot room.
On the 3rd of February she distinctly felt a worm moving about in her
left upper eyelid, and came at once to me, but before she arrived this
feeling had gone, and I failed to discover any signs of the parasite. She
returned on the 6th of February with the statement that not only had she
felt the worm moving about in the left lower lid, but that it had also
been distinctly seen wriggling under the skin. I saw her three different
times that day, but failed to observe anything that might indicate with
certainty the presence of a parasite, although she sat in front of a
hot fire and had a succession of hot poultices applied, so as to tempt
the worm to the surface. On the third visit, as she felt the wriggling
of the worm, and as there seemed to be a little fulness at one point in
the left lower lid, I decided to cut down at that point and search for
the parasite. This I did with Dr. Mackay’s assistance, having first of
all applied clamp-forceps so as to prevent the worm escaping if it were
there. I failed to find any parasite, although I made a careful search,
and the patient showed great nerve and steadiness under operation, but I
noticed a distinct narrow channel or burrow parallel to the edge of the
lid, and crossing about the middle of it, which gave me the impression of
being a burrow by which the worm had moved across the lid.
Two days later Miss H⸺ came complaining of a swelling in the right
temporal region. This swelling seemed pretty deeply situated, and firm
palpation failed to reveal any corded feeling such as might indicate the
presence of a worm.
On the 13th of February she felt the worm wriggling across the right
upper eyelid, and then it appeared to her to remain coiled up under the
skin. She bound the eye carefully up and came at once to the infirmary.
I examined the lid and noticed a fulness at the upper inner part, which
might be a coiled-up worm. By pressure of the fingers I attempted to
force the swelling towards the edge of the lid, but I could neither
see nor feel any movement such as might be expected from the presence
of a worm. As, however, the patient’s sensations were very distinct, I
determined to make an exploratory incision. I applied the clamp-forceps
and made a free incision over the region of the swelling, but found
the chief cause of the fulness to be a small deposit of fat, which I
cut away, and then proceeded to explore the neighbourhood carefully.
After some dissection I found a very fine transparent filamentous
body. On drawing upon it with forceps it came away with a snap. It
was much smaller in calibre and shorter than the usual _Filaria loa_,
and I concluded that it was only a portion of a filaria—the main part
being caught between the blades of the clamp-forceps. The forceps
being removed, further exploration was made, in which I was assisted
by Dr. Mackay, and after some dissection a well-marked _Filaria loa_
was discovered deeply embedded in the muscular tissue and removed with
forceps. The edges of the incision were brought together by a couple of
fine sutures, and healing occurred by first intention.
The worm thus removed measured about 30 mm. in length and nearly 1
mm. in thickness. It was firm and transparent like a small piece of
fishing-gut. It tapered at either extremity to a blunt point, the tail
being rather sharper-pointed than the head. At the distance of about 9
mm. from the caudal end an opening existed in the wall of the parasite,
through which protruded a filamentous coil, which subsequent microscopic
examination revealed to be the uterine tubes filled with ova in all
stages of development up to embryo filariæ. Notwithstanding the amount
protruded, the interior of the parasite was yet to a great extent
occupied by oviduct, the alimentary canal being apparently comparatively
small in size. The wall seemed to be chiefly composed of muscular fibre,
the transverse striæ of which were readily visible at all parts. The
semicircular projecting tubercles, which Dr. Manson is inclined to
view as serving to facilitate the gliding movements of the parasite by
enabling it to get a purchase on surrounding parts, were very numerous
towards the caudal end, fewer in number at the centre, and very sparsely
distributed at the head extremity. Near the oral end of the worm a small
general projection of the wall existed on one side, probably due to a
partial rupture produced by injury.
The small piece of the worm I first removed in the course of the
operation proved on microscopic examination to be part of the oviduct
containing embryo filariæ.
I will submit my specimen for more careful and thorough examination and
report to Dr. Manson, who is entitled to speak with such authority on
this subject.
During the last six months I have at intervals examined blood drawn from
Miss H⸺ at various periods of day and night, but have never been able to
discover the presence of any filariæ.
My patient has several times directed my attention to ill-defined
swellings under the skin of the forearms a little above the wrists, over
the dorsal surface of the radius, more marked generally in the right arm.
The surface of the swellings was not quite uniform, but did not give one
the idea of being produced by a coiled-up worm. The swellings measured
about half an inch in diameter. They were not painful, but occasioned a
feeling of stiffness when the arms were used. The swellings occurred at
irregular intervals, and were generally most marked in the mornings. Cold
had no influence in dispelling them; on the contrary, the application of
cold water on one or two occasions seemed to bring the swellings forward.
My patient informs me that natives of Calabar, and others resident for a
time there, are subject to such swellings in the forearms and wrists, to
which the natives apply the term “Ndi töt,” or swelling. These swellings
she has only suffered from since her return home.
I have further a correction to make in the history of my patient I
previously submitted. It would appear that while she was most careful
with regard to the purification of her drinking-water by boiling
and filtering, she was for ten days prior to leaving Old Calabar so
completely prostrated as to be unable to attend to any household matters,
and the person who undertook her duties was unacquainted with the
procedure employed for purifying the water. It might thus readily happen
that she at that time partook of impure water containing embryo filariæ.
As she had no symptoms of filaria till after her return home, this
_might_ explain their entrance into her system.
It is easy to understand how the embryo filariæ may enter the system,
although their presence in impure water has not yet been demonstrated.
And it is easy to conceive that, having entered the system from the
alimentary canal, they may breed and bring forth a large crop of embryo
parasites. But the chief difficulty consists in determining how these
embryo filariæ escape from the bodies of those affected with the disease,
and get deposited in the impure water and thus propagate the disease.
In the case of the _Filaria sanguinis_ this is accomplished by the
mosquito which constitutes the intermediate host; but as in the case of
my patient, as well as in the case reported by Dr. Logan of Liverpool,
careful examination of the blood failed to reveal the presence of embryo
filariæ, some other system of propagation than that by blood-sucking
insects must be looked for. Possibly the embryo parasites may be
discharged along with some of the excreta from the body, and from faulty
sanitary arrangements find their way into drinking-water. Whether this be
so or not, future investigation will probably show.
* * * * *
_Report on the structure of the female parasite_ (by Dr. MANSON).—Female
_Filaria loa_: length, 3·25 cm.; breadth, 0·5 mm.; ova at morula stage,
0·03 by 0·02 mm.; length of outstretched embryos in uterus, 0·25 mm.
As regards her general appearance, the female _Filaria loa_ resembles the
male parasite, only she is considerably larger and her tail is straight,
tapers to a diameter of about 0·1 mm., and is then abruptly truncated.
The mouth, the head, the stout muscular ring just posterior to the mouth,
the stout longitudinal muscular bands, and the bosses on the integument
resemble exactly those of the male worm. In consequence of the mutilation
of the specimen it is impossible to say where the vagina opens, or where
the anus is placed. The uterine tubes are stuffed with embryos at all
stages of development. The more mature embryos resemble in size and shape
those of _F. nocturna_ and _F. diurna_, but in consequence of the method
of mounting it is impossible to say if they are possessed of a sheath
or not. If they are possessed of a sheath, I should say that they are
practically indistinguishable from the parasites mentioned.
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