Case of Filaria loa

by Douglas Argyll Robertson

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.