Part 2

We have next several cases that were carefully observed and recorded by M. Guyot, a French surgeon,[2] who had made many voyages to the Angola coast of West Africa. The first case in which he discovered the filaria was that of a negress in whom, after several examinations, he noticed a ridge of the conjunctiva resembling a varicose vein, which induced him to make minute openings over it to empty it. On pricking the elevated conjunctiva with the point of a lancet he was surprised to observe the projection disappear. The patient at the same time stated that she felt something move in her eye, and that the movement was deep-seated. He suspected that this could be nothing else than a roving worm (_ver ambulant_), which sometimes appeared under the conjunctiva, sometimes dived into the posterior parts of the eye. From inquiry he found that a worm in the eye was common enough among natives of that land, and that it was called a “loa,” and he consequently applied the term filaria loa to the affection. He saw the worm on many occasions in the eye of the negress, but whenever he touched the spot where it was it retreated to the posterior parts of the orbit. On that voyage he saw several negroes with this affection, for which he employed various collyria without effect.

In 1777 he made another voyage to the coast of Angola. Having many negroes on board the ship he renewed his researches, and found several individuals affected with the disease. As no benefit had been derived from the applications he had previously used he proposed to extract the worm through a small opening in the conjunctiva. To effect this it was necessary to fix the worm, to which end he employed dissecting forceps, without, however, being able to seize it.

On another occasion he employed a ligature needle of medium size, with which he pierced the conjunctiva by the side of the worm, and passed it between the worm and the sclerotic, making it emerge at the opposite side. By this manœuvre he was able to raise the fold of conjunctiva along with the worm on the concavity of the needle. This fold he divided, and drew out the worm without mutilation. The operation required to be done very quickly, otherwise the worm escaped and disappeared, sometimes for a very long time. Of five negroes upon whom he thus operated he was only able to remove the worm twice. The worms were about fifteen lines in length, and a little less thick than a violin string. He did not think the worms were a species of dracunculus, for they were quite white, firmer, and less long in proportion. He never saw the worm make an opening for itself. In the seven voyages he had made to the Angola coast he had never seen a negro affected with dracunculus. Other surgeons who had sailed on these coasts assured him they also had seen no cases, which made him conclude that the negroes of that country are not subject to dracunculus. The cases on which he operated were healed in twenty-four hours.

We next find M. Clot at a meeting of the Académie Royale des Sciences in December, 1832, referring to the case of a negress, who suffered from a dracunculus under the conjunctiva of the eye. It appeared now and then gliding between the conjunctiva and sclerotic, lifting up the conjunctiva. This case appears to be one that was seen by Dr. Roulin at Monpox in America.

Another case is mentioned by Dr. Sigaud in his work on the ‘Climate and Diseases of Brazil.’ He states he was witness in 1833 of the extraction, by M. dos Santos, of a filaria situated in the orbit on the surface of the sclerotic of a negress.

In 1838 Dr. Guyon made an interesting communication to the French Academy of Sciences, in which he narrated the case of a young negress affected with two filariæ, one in the right and the other in the left eye, but occasionally both appeared in the same eye; the passage of the worm from the one eye to the other occurring with great rapidity through the cellular tissue under the skin at the root of the nose. The filariæ were in different eyes when the operator (Dr. Blot of Martinique) extracted the filaria from the left. Some hours after, when he returned to extract the other worm, he found that it had passed to the left eye, from which he extracted it by a fresh incision.

The first cases reported by an English surgeon were by Dr. Loney, a naval surgeon, occurring in two Kroomen, whom he saw while cruising on the West Coast of Africa during 1841-2. In both he succeeded in extracting the parasite.[3]

Another case was observed by Dr. Mitchell at Trinidad in the person of a young negress, in whom the worm appeared at long and uncertain intervals for four or five years before he had the opportunity of seeing it. At length in 1845 Dr. Mitchell saw the worm twisted like the letter S lying motionless under the conjunctiva, midway between the edge of the cornea and the inner canthus. Extraction of the worm was deferred to enable six or seven of his medical brethren to observe so unusual an appearance, with the result that when they assembled the following morning the parasite had removed itself to deeper parts.[4]

A case is also recorded by Gervais and van Beneden,[5] in which M. Lestrille succeeded in 1854 in extracting a filaria from a negress, and Dr. Guyon once more, at a meeting of the French Academy of Sciences in 1864, exhibited another filaria, which had been removed by a French naval surgeon from a negro of the Gaboon. The filaria was of unusual size, measuring fifteen centimetres. Its length was such that the whole of it could not be seen at one time below the conjunctiva, part always remaining embedded in the deeper parts of the orbit.[6]

Dr. Morton[7] reports a case occurring in a negress residing at Gaboon in West Africa, in which a native woman succeeded in extracting the parasite. The worm, preserved in gin, had been sent to him by a missionary, the Rev. Dr. Nassau, in the district, who informed him that although he had been very many years in that country, and had often heard of the parasite, this was the first specimen he had been able to secure. The missionary himself appeared to be also affected with filaria, which, however, did not appear on the eye, but could, he said, occasionally be felt under the skin of the fingers, and once in the skin of the lower eyelid, from which position he attempted himself to remove it with scalpel and forceps, but he did not succeed, the worm wriggling away across his cheek. The worm that was sent to Dr. Morton measured 16 mm., but was in too badly preserved a state to permit of accurate examination.

Lastly, in Dr. Davidson’s work on hygiene and diseases of warm climates (p. 962) Dr. Manson, who writes the article on filaria, reports the case of a negro who had been affected with _Filaria loa_, and in whose blood he afterwards found the _Filaria diurna_, and raises the question whether the _Filaria loa_ may not turn out to be the female parental form of the _Filaria diurna_.

I am afraid we must confess that we are as yet very ignorant of many points connected with the life history of the _Filaria loa_. With the adult female parasite we have a limited acquaintance, but till now we are ignorant of the appearance of the male worm. The larvæ have been observed in the interior of the adult, but what their further course is, what transmigration may occur, ere they reappear as fully formed filariæ under the conjunctiva has yet to be discovered. The only observation that bears at all upon this question is that made by Dr. Manson and reported in Dr. Davidson’s work, that in one case of _Filaria loa_, the _Filaria diurna_ was afterwards found in the blood. With the view of ascertaining whether the _Filaria diurna_ was present in the blood of my patient Miss H⸺, and also with the view of getting a report as to her general medical condition, I got my friend Dr. Alexander Bruce to undertake the examination.

It must, however, be borne in mind that in her case the filaria removed proves to be a male, and, unless she were affected with the female parasite as well, no embryos could be expected in the blood.

_Report by Dr. Alexander Bruce, October 16th, 1894._—“Miss H⸺, missionary to Old Calabar, went there at the age of twenty-two, has been out there ten years altogether; first was out for two years, then furloughed for one year on account of an attack of intermittent fever which turned her hair grey, but was not otherwise very severe in type. Then she was out for four years and home for one year on furlough. Then was out for seventeen months, invalided home in January, 1894, for remittent fever, gastritis, and a form of dysentery and great anæmia. The remittent fever began in December, 1893, with delirium at beginning, and fever which rose daily to 102° and 103° F. She was sent to sea in ten days, and on the way home the temperature on one occasion rose to 107°; this was reduced by ice-pack. Improvement was slow, being retarded by the gastritis and dysentery, and the tendency to pyrexia did not abate till the end of June. The gastritis was indicated by intense pain (agony, she called it) in swallowing anything, whether solid or fluid. The bowels now move only once daily or less frequently, and the motions are accompanied by small flakes of mucus (formerly by blood). There was always great mental depression during the attacks of dysentery.

“The arms became, since June, stiff and swollen, especially on awakening from sleep (whether at night or during the day), and the hands felt ‘numb,’ ‘dead,’ ‘as if asleep,’ or ‘as if they didn’t belong to her.’

“She was so weak that she had to remain in bed till the beginning of April. Since then, after a visit to Crieff, she has improved rapidly, and can now walk two or three miles easily. She now has a fairly good colour, has good appetite, and no pain in the stomach. Examination of the circulatory system shows absolutely nothing abnormal, no dilatation of the ventricles, no arterial, valvular, or venous bruits. The respiratory murmurs and the percussion note of the lungs are normal. The liver is not, and the spleen is, just appreciably enlarged. The blood flows readily from a prick in the finger; it is rich red in colour. The red corpuscles are well-coloured, well-formed, and form rouleaux readily. There is a slight increase in the white corpuscles. Specimens of the blood drawn at 9 a.m., 8 p.m., 9 p.m., 1 p.m., and dried on the slide showed no evidence of filaria of any kind.

“The forearms presented, on the anterior and posterior aspects, slight flattened doughy swellings, which had no definite boundary and were not painful to pressure. There was no alteration in the colour of the skin over them.”

We are still at a loss to account for the entrance of the worm into the body. There are, I think, two different channels by which it might possibly find access. First, by the passage of the embryo filariæ directly through the conjunctiva, being brought in contact with the eye in water used for washing the face or bathing the eye. This I think an unlikely means of entrance, as in my patient special pains were taken to avoid such a possibility, and yet she became affected with the disease, and the power of the worm to penetrate skin or mucous membrane has never been demonstrated. Second, by the swallowing of the embryo filariæ along with articles of food or drink. Although in the case of my patient excellent measures were taken to secure the purity of the water-supply, and although the nature of the food was such as not readily to lend itself to the conveyance of impurities, still I think recent researches, made more particularly by Dr. Manson with regard to the development of the _Filaria sanguinis_, render it probable that the ova of the _Filaria loa_ are, as suggested by Dr. Manson, taken into the circulation of the patient affected by the mature female parasite. That then some insect of predatory habits, drawing its food-supply from this polluted stream, becomes, in its turn, the host which supplies the necessary elements for the further development of the parasite. This insect, in its turn dying, deposits the embryo filariæ in water, which, being used for drinking purposes, permits the parasite once more to affect man. Which the insect is that probably plays the part of intermediate host is as yet unknown. This view is purely hypothetical, but I think, reasoning from analogy, the most probable one of the development of the _Filaria loa_.

The geographical distribution of this parasite appears to be a very limited one, as almost all, if not all, of the persons affected, whose cases have been reported, have either been natives of or been long resident on a limited area of the West Coast of Africa, including Congoland and Old Calabar. If Dr. Manson’s view as to the mode of development of the worm be substantiated, then naturally the area of the disease must necessarily be limited to the regions in which the intermediate insect host is to be found.

The fully grown worm may, judging by some of the cases recorded, infest the human subject for a good many years, and may yet not give rise to any very serious symptoms. It possesses very considerable locomotive powers. It is capable of wandering at will from one eye to the other, to disappear into the deeper parts of the orbit, to wander under the skin of the eyelids, and even to make excursions in the temporal region. These seem to be the limits of its excursions. No doubt the Rev. Dr. Nassau (the missionary at the Gaboon) had sometimes sensations of a filaria under the skin of the fingers as well as under the skin of the eyelid, but it is doubtful if this was a true case of _Filaria loa_, and even then if the worm had made its way from the fingers to the eyelid. At the same time it must be borne in mind that there are few regions of the body in which the skin is so thin as in the eyelids, whereby the presence of a small filamentous body can easily be discerned. The parasite might readily move about under the coarser cutis of other parts and yet escape detection.

The sensitiveness of the parasite to cold appears to be fully established by the experience of my patient and Mrs. H⸺, and it is possible that a prolonged residence in a cool climate may eventually prove fatal to the worm, as seems to have occurred in the case of the Rev. J. L⸺. All the cases previously recorded have occurred in negroes, but those I have brought forward prove that Europeans are also susceptible to the attacks of this worm.

I think I am warranted in saying that the disease is not very rare in the district favoured by the parasite, as, although the number of cases reported is small, the irregular intervals at which the worm comes to the surface, and the slight irritation or annoyance its presence causes, often prevent those affected seeking surgical advice; while it must be admitted that medical assistance is not very readily procured in large parts of the district where cases occur.

The interest connected with the elucidation of the obscure points in the natural history of the worm will, I trust, stimulate those of our profession residing on the West Coast of Africa to undertake the further necessary investigations.

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