Filarial worm

“ 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. ”

“ Twisted round the worm, and apparently attached to it near its centre, was a much finer, less firm, transparent filamentous body, which I at first thought might possibly prove to be a second young filaria, or even the male filaria, but which on further careful microscopical examination appears to be the alimentary canal of the worm protruded through an opening in its musculo-cutaneous wall, caused by the forcible grasping of the parasite with the forceps. ”

“ The worms could be obtained from day to day by simply pricking any portion of the body with a finely pointed needle. To this hæmatozoon Lewis gave the trinomial term Filaria sanguinis hominis, which thus fitly distinguished it from the Filaria papillosa hæmatica canis domestici described by Grube and Delafond. Dr Lewis found the average size of the parasite to be 1/75′′ in length by 1/3500′′ in breadth. He observed that while it exists in the blood the body is enclosed in a delicate transparent tunic or cyst. The worm was never absent from urine in chyluria. ”

“ Another species of thread-worm (Filaria lacrymalis) is occasionally found in the horse between the lids and eyeball. It is a comparatively small and harmless parasite, the males measuring 1/2′′ in length and the females 2/3′′. It also infests the ox. Both the large and small eye-worms are viviparous, and, not improbably, both of them are the means of conveying embryonic Filariæ into the circulation. Be this as it may, we owe to Dr Sonsino the discovery of hæmatozoa in an Egyptian horse. The larval worm was provisionally named by him Filaria sanguinis equi. ”

“ Four years later Bancroft, in Brisbane (Queensland) , discovered the adult form, and Cobbold named it Filaria bancrofti. Since that time the subject has rapidly expanded, and its great practical importance in tropical pathology is now recognized.
Nomenclature of the parasites.— I have pointed out that Lewis's microfilaria* [1] is not the only blood-worm in man, and that the human circulation is the habitat of the larvae of no fewer than five, possibly of six or even more, distinct species of filariæ. ”

“ 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. ”

“ Once such an insect is caught on one of the threads it is lost beyond all hope. There it sticks, struggle as it may. The vibrations caused by its struggles attract the attention of the glow worm which quickly winds up the hanging thread. If it is not hungry at the moment it has been observed to play with its victim, [Pg 5] drawing in and then letting out the line after the manner of a fisherman. Finally the prey is drawn into the silken sheath and entirely devoured, chitinous shell and all. It is not merely sucked, as is the fashion of the spider or the fly. ”

“ Not only unicellular organisms, such as bacteria and protozoa, but also the eggs, embryos and larvæ of parasitic worms have been found to be transported by house-flies. Ransom (1911) has found that Habronema muscæ, a nematode worm often found in adult flies, is the immature stage of a parasite occurring in the stomach of the horse. The eggs or embryos passing out with the feces of the horse, are taken up by fly larvæ and carried over to the imago stage. ”

“ And likewise the great common Earth-worms, for curing it. Neither is it without ground that this Worm [or Scarabæus] we mention, far exceed all the rest of them that are endued with Virtues, healing Diseases. The Cantharides come far short of it, and the sky coloured Flies, which are formed onely in Carkasses, are far short of the Cantharides. In the next place follow those greater Flies, that usually stay in men’s houses, and keep buzzing about till they can find some raw Flesh, whereon they cast their filth in the likeness of small Eggs or Knits, which become Worms in a days time. ”

“ There is yet another Filarian worm, a pest to the poultry-yard, the Gape-worm, Sclerostoma syngamus. This parasite is widely distributed, and is invested with special interest, since it produces disease, and kills annually thousands of young chickens, pheasants, partridges, and many of the larger kinds of wild birds. The worms find their way into the windpipe or tracheæ, through the drinking water, while in the embryotic or cercarian stage of existence, and their increase is so rapid, the birds quickly die of suffocation. ”

“ The female glow-worm, the light-giver, is wingless; the male is winged. The latter, however, has but little of the light emitting power possessed by the female. Only the light-givers are collected, and being destitute of the first attribute of an insect, wings, are set down in popular parlance as worms. Old mossy banks, damp hedgerows, and shaded woods are the loved haunts of the fireflies, and the warm nights of the soft summer months most induce them to burn their soft lustre. Some widowed worm or firefly flirt may shed her luminous self in the darkness even on into dying summer or autumn. ”

“ It is the giant of a family of white, red, yellow, green, purple, and violet worms whose habitat ranges from sea bottoms to jungle treetops. The worms shoot poison-tipped harpoons out of their brains. Most can shrink at will to less than a third of their ordinary length. They always shrink when they die. Some can break up into hundreds of fragments, each of which will grow into a complete new worm. ”

“ When seen swimming in the water it presents the appearance of a long, many-ringed worm, which impels itself through and by the aid of its hundreds of flat, oar-like legs. Closer inspection reveals the startling fact that this seemingly single worm is really a multiple worm—six or more individuals being joined together, thus forming a living chain. This creature reproduces itself by fissigemation; that is, when the young worms arrive at a certain age they separate from the parent worm and begin life as individuals. ”

“ Unless the ova are too large they often succeed, and the eggs are deposited uninjured in their feces, in some cases up to the third day at least. The eggs may also be carried on their legs or bodies. Under suitable conditions, food and fluids may be contaminated with the eggs of various parasitic worms by flies, and in one case infection of the human subject has been observed. Feces containing tape-worm segments may continue to be a source of infection for as long as a fortnight. ”

“ The embryos of three species of Filaria infest the blood of man, chiefly in the tropics. One embryonic species is found in the blood of infested patients by day, one by night, and one during both day and night. The length of the embryos varies from 1 ∕ 75 to 1 ∕ 125 inch, and its width from 1 ∕ 3000 to 1 ∕ 3500 inch. The night embryo, which is the most common, is produced by the Filaria Bancrofti. This adult worm infests the lymphatic system of man, sometimes reaching a length of three to four inches. ”

“ As before remarked, the whipworm has been known to produce severe symptoms in man, and it occasions “scour” in the sheep. The eyes of cattle are occasionally infested by Filaria lacrymalis and F. papillosa. The last named is the common eye-worm of the horse. On Feb. 27th, 1875, Dr Edward L. Moss, of H.M.S. “Alert,” brought me three examples of a nematode which I referred to Filaria terebra. Dr Moss obtained these parasites in 1874, during the time that he had charge of the Naval Hospital at Esquimalt, Vancouver’s Island. ”

“ Some other filariform nematodes have been imperfectly described. Of these, Gescheidt’s Filaria oculi canini (F. trispinulosa, Diesing) was probably a sexually-immature worm, and the same may be said of the encysted worms found by Mr Mather in the mucous coat of the intestines and in the liver ducts and acini (Filaria hepatica, Cobbold) . Of more interest is Leisering’s hæmatozoon (Strongylus subulatus) . These minute worms occupy the veins, the largest females not exceeding 1/12′′ in length. They are viviparous, and thus form another source of embryonic hæmatozoa. ”

“ I went and told Schomburgk, who examined it, and at once diagnosed it as a very bad and greatly neglected case of filaria, otherwise guinea-worm. These dangerous parasites burrow under the human skin, generally in the feet or legs, and the female lays eggs, giving rise to abscesses, and also causing grave functional disturbances. They are removed by very slowly twining them round a stick, and the natives assert, and apparently with some measure of truth, that if the worm is broken in the process, the death of the person affected will ensue. ”

“ The roundworms are slender, smooth, cylindrical worms pointed at both ends. They are all very long in proportion to their diameter, although their actual length may be short. Some species are of microscopic size; as the Trichina worm, which is about 1/20 in. long; while the guinea-worm, one of the worst parasites of man, may reach a length of six feet. Many of the roundworms are parasites living in the various organs of other animals. Some, however, lead an independent free life in water or in damp earth. ”

“ The adults which occur in enlarged glands, etc., get eventually destroyed by inflammatory reaction, so that larvæ are no longer being produced, while the enlarged gland, etc., which the adults have produced remains. This explanation assumes that the larvæ of the original worm die in the circulation or elsewhere, e.g., kidney, but we have no evidence as to the duration of life of larvæ in the human body; but also it assumes that a person cannot be reinfected with filaria, for otherwise there is no reason why the diseased should not be infected in the same proportion as the non-diseased. ”

“ The female of this insect is very luminous, and has no wings. The light always becomes brighter when the worm is in motion, and it can withdraw it when it pleases. When the light is most brilliant, it emits a sensible heat. When a glowworm is put into a phial, and this is immersed in water, a beautiful irradiation takes place. If the insect be crushed, and the hands and face rubbed with it, they have a luminous appearance, like that produced by phosphorus. ”

“ Every few days my forearm or my hand was swollen from the presence of this worm. I have seen a ridge across the nose where a colony was passing. I have been told that the eye-worm and the worm that circulates beneath the epidermis are not identical. I am not sure about it; but I hope there are not two of them.
The guinea worm belongs to the same family, with the beautiful name, the Filaria. The larva enters the human body in drinking-water and makes its way to the subcutaneous tissue of its host’s leg, where it often causes serious abscesses. ”

“ 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. ”

“ Here the worm, always lodged in the intestines, grows with extraordinary rapidity, and fulfils all the conditions of a true parasite. In a fertile soil it extends itself and produces young as long as it has any life, and in no group of the animal kingdom do we find any fecundity to be compared to that of this worm. Boerhaave described a broad tape-worm, three hundred ells in length. ”

“ The first female which presents itself allows us to answer this question. It is not a parasitical worm, at least under this form, because each female contains only one or two eggs. Parasites have so few chances of arriving at their destination, that two young ones would not be sufficient. They must have hundreds or thousands, and then the chances are against them. This worm is evidently a Rhabditis, but is it that which lives in the earth, or an allied species? ”

“ Similar feeding experiments upon fishes and reptiles also failed. The embryo, when removed from the egg, measures 1/104′′ in length. It is vermiform, having a pointed head and simple mouth. Balbiani describes the buccal cavity as containing a protractile stylet. Notwithstanding the negative results obtained by Balbiani’s experiments on fishes, Schneider (from anatomical data, which Leuckart confirms) has placed it almost beyond question that the worm hitherto known as Filaria cystica is the sexually-immature Eustrongylus gigas. ”

“ When worms are wanted for immediate use, and no provision has been made, the way to scour them quickly, is, if lob-worms, to put them all night in water; brandlings must not remain above one hour in it, and both sorts must be then put with fennel into the angler’s worm-bag.
Worms of different kinds inhabit the intestines; but except when they exist in very great numbers, they are not so hurtful as is generally supposed, although the groom or carter may trace to them hidebound, and cough, and loss of appetite, and gripes, and megrims, and a variety of other ailments. ”