Cysticercus

“ Here, too, the cysticercus occurs in two forms—sometimes the cysts are roundish or oval, solitary or multiple, and at other times Cysticercus racemosus occurs.
Tænia saginata.
Occurs in the small intestine of man. It is characteristic of the habit of life of this parasite that once it has become mature its proglottides are dropped off daily in increasing numbers because its growth is extraordinarily rapid. The joints are discharged generally spontaneously during the whole day without a stool. ”

“ Even more disastrous may be the result, should some ripe joints of a mature worm work their way from the intestine back towards the stomach. Should this happen (and though it has not been directly proved, the possibility is to be reckoned with) , the result would be the release of vast numbers of embryos capable of inflicting fatal injury on the host. An abnormal Cysticercus of this species is probably the Taenia {80} (Cysticercus) acanthotrias Weinl. (see, however, Leuckart, loc. cit. p. 711) .
Taenia (Hymenolepis) nana v. Sieb. ”

“ If, after having prepared a Cysticercus, newly extracted from a pig in the way we have pointed out, we examine it with a microscope on M. Schulze’s heating table, we find that usually it begins to move after 30° or 35° C., and each moment with greater activity, especially after 38°, 40°, 42°, 44°, 45° C. The temperature being raised progressively, we see that the Cysticercus cellulosæ puts a stop to its movements occasionally at 45–46° C., seldom at 47° C., more frequently at 48° C., sometimes at 49° C. ”

“ When the hooks and suckers are fully formed, the head undergoes a process of evagination, so that what was previously a hollow cavity becomes a solid cylinder, and the hooks, which were below the suckers, come to lie above them. Mature bladder-worms vary in size from Cysticercus fasciolaris, the size of a pea, to Cysticercus tenuicollis, six inches or more in length.
The development into the adult tape-worm takes place only after the Cysticercus has been swallowed by the permanent or definitive host. ”

“ Haubner and Küchenmeister, 1855; Leuckart, 1856; Mosler, 1865; Gerlach, 1870; etc.) , but success did not attend the efforts to make Cysticercus cellulosæ establish themselves in the intestines of pigs, dogs, guinea-pigs, rabbits and monkeys (Macacus cynomolgus) , and so become adult Tæniæ; the attempts, also, to infect dogs with cysticerci by means of ova were likewise, as a rule, abortive.288
The development of Cysticercus cellulosæ takes two and a half to three or four months ”

“ Every living cysticercus which penetrates into the stomach, instantly quits its torpid state: it gets rid of its useless parts, abandons its former cavity, penetrates into the intestine, attaches itself by its new hooks and its suckers to the enclosing membranes, and grows with such rapidity, that in less than six weeks, we often find a tape-worm many metres in length. ”

“ Plate IV., No. 100, shows an adult specimen of the latter with rostellum suckers, and three successive segments, the last of which is the ova sac. The water-vascular system is represented coloured by carmine. This parasite infests the human body as frequently as many other species. My accurately-drawn figure is copied from Cobbold’s “Introduction to the Study of Entozoa.”
Cysticercus fasciolaris is developed within the liver of white mice; Cysticercus cellulosæ in the muscles of the pig; hence we have the diseased state of pork familiarly known as “measly pork.” ”

“ In the great majority of species only one tape-worm head is produced, and such bladder-worms constituted the genus Cysticercus of the older helminthologists. In certain cases, however, notably in the worm which produces the “staggers” of sheep, numerous heads are formed in the wall of each bladder; such larvae formed the genus Cœnurus, but apart from their polycephalous condition there are no structural peculiarities calling for special notice. ”

“ Our great initiator into the world of parasites, Mons. Siebold, arrived also at a conclusion which could not be maintained. Having observed, with his habitual sagacity, that the cysticercus of the mouse is the same worm which lives in the cat, he published his opinion that the eggs of this tænia had lost their way in the mouse, that the young worms had become sick there, and that in the cat alone, they could be healthily and completely developed. It was like a plant lost on a soil where it could not live, and still less flourish. ”

“ Every pathologist is familiar with gritty particles in the various viscera of man and animals, but few are probably aware how constantly these are dead and degenerated Cysticerci. The gritty particle itself may be reduced to the merest point, no larger than the receptaculum capitis of the Cysticercus itself, and in course of time it will disappear entirely. Practically it is satisfactory to have experimental evidence of the fact that cattle, as well as other animals, however extensively measled they may have been, can become thoroughly cleansed of the disorder by nature herself. ”

“ Its position can also be reversed, and the proglottides in the gut become thus discharged by vomiting.
The diagnosis depends upon the proglottides being generally discharged in pieces in the stools, or eventually an examination for eggs. Larval infection (Cysticercus cellulosæ) occurs also in man through auto-infection or through food.
Cysticercus cellulosæ of the skin and subcutaneous tissue occurs very seldom singly; as a rule they are found in hundreds and thousands in the same individual. ”

“ The Cysticercus cellulosæ of the pig dies sometimes at 45° C., more frequently at 47° C., ordinarily at 48° C., very seldom reaches alive 49° C., and is quite an exception when it resists for a few moments the temperature of 50° C., so that we can say that the Cysticercus brought gradually up to this temperature most assuredly dies if it is kept there longer than one minute. ”

“ As the characteristic lesions of cysticercus disease are to be found in the depths of the muscular and connective tissues, and as the external symptoms may be regarded as of doubtful significance, the diagnosis can only be confirmed during life by manual examination of the tongue. ”

“ In the pig the diagnostic sign of swellings of the glands or ‘cyst’ under the tongue is not found in ‘Cysticercus,’ and the disease called ‘measles’ is not ‘Cysticercus,’ but a mere superficial inflammation of the skin and a symptom of fever. ‘Cysticercus cellulosus,’ as its name shows, infects the cellular tissue only of the pig, and cannot be discovered in life by any abnormal condition of skin. ”

“ In most other cases the tail is not distinguishable, and the body of the larva is separable only into a scolex invaginated with a bladder ( = hind-body and tail) . This form of larva is known as a cysticercus. In some genera a “urocyst” is formed, the tail of which gives rise to a new cyst and a fresh scolex. ”

“ Cysticerci occasionally occupy the brain of the pig in considerable numbers. Florman recorded a case of this kind where their presence gave rise to vertigo in all respects resembling the gid ordinarily produced by Cœnurus in the sheep. As regards the larger cestode larvæ, Cysticercus tenuicollis and Echinococcus veterinorum are of frequent occurrence. One not unfrequently encounters the former in the mesentery, whilst the liver of the hog is sometimes so crowded with hydatids that scarcely any of the glandular substance of the organ remains visible. ”

“ Some parasites are so strictly confined to one species of host that, even when artificially introduced into animals very closely related to their normal host, they do not thrive, but sooner or later, often very quickly, die off, and very rarely establish themselves. For example, repeated attempts have been made to rear the adult Tænia solium in the dog, or to rear Cysticercus cellulosæ in the ox, or the Cysticercus of Tænia saginata in the pig, but they have always proved unsuccessful. ”

“ But the danger of its presence in the body of man, or in the flesh of pigs, lies in the fact that the larva or bladder-worm (known as Cysticercus cellulosae) can live in the most varied organs. Thus if by accident a mature proglottis be eaten, the embryos escape, bore their way into the wall of the stomach, and entering the portal vein, may reach in time the muscles, the brain, the eye, or even the heart itself, and attain the cystic condition. ”

“ The calf was put to and remained with a foster mother until it died from disease of the larynx on the 15th of the following July. The animal was ill-treated by its foster parent, and at the post-mortem I observed a large intercostal cicatrix, evidently the result of injury. In this case I devoted several hours to the exploration of the muscles and viscera. Not a trace of the Cysticercus bovis could be found in the muscles or connective tissues, but the liver contained scores of perfectly developed measles, besides hundreds of others in various stages of calcareous degeneration. ”

“ The head of the worm can sometimes be seen shining through as a whitish speck. The only symptoms are those of a slight irritation of the connective tissue and some difficulty in closing the lid; larger cysts dislocate the globe. The diagnosis has the rapid growth of the cystic tumour to support it; there is the possibility of its being mistaken for a foreign body (Kaldrovils718) . After division of the connective tissue capsule extraction is easily performed. It is most rare for the cysticercus to occur in the orbit. Suppuration of the cyst may have serious consequences for the eye. ”

“ A larger or smaller quantity of fluid is present, and also a connective-tissue sheath; the host is a vertebrate. Cysticercus (true bladder-worms) , Piestocystis, Cœnurus, Echinococcus.
II. The caudal bladder arises from the proscolex by budding, that is, by the formation of new parts; there is no connective-tissue sheath, and the host is an invertebrate. Cysticercoidei, Leuckart. (a) Caudal bladder formed by endogenous budding; the head is surrounded, not only by the body of the worm and the caudal bladder, but also by the blastogen (proscolex) . ”

“ These experiments have a great value, both scientific and practical, as they show, on one side, which is the lowest intensity of heat sufficient to kill always the Cysticercus, the Trichina, and other parasites, reducing thus by far the tenacity of life generally attributed to a large number of Helminths and corresponding larval forms. ”

“ Some slight notice, however, will be given of the entozoa of each of the eleven families into which the order may be divided.
The squirrels (Sciuridæ) are liable to be infested by the common liver fluke (F. hepatica) , and also, it is said, by a cysticercus (C. tenuicollis) . I have never encountered this bladder worm, but in 1864 I described some polycephalous hydatids (Cœnuri) which I obtained from the viscera of an American squirrel. I think the host was of the same species (Sciurus vulpinus) as that from which Mr Chapman has since obtained an example of Echinorhynchus (E. moniliformis) . ”

“ Even in the case of underdone meats, in whatever way prepared, it is usually only a small portion which is unaffected by cooking. As we have seen a temperature of 140° Fahr. is sufficient to kill the Cysticerci.
The successful rearing of pork measles by experimentation with the eggs of T. solium has been accomplished by many helminthologists, amongst whom may be particularised Van Beneden, Leuckart, Küchenmeister, Haubner, Gerlach, and Baillet. The converse experiment of rearing the adult worm from the Cysticercus was first successfully undertaken by Küchenmeister on a condemned criminal ”

“ At four equidistant points near the bottom of the invagination the suckers are developed, and at the lowest part of the cavity the rostellum (and the double circlet of hooks in the armed species) is formed. Surrounding the head-rudiment on that surface which is towards the cavity of the bladder is a thin layer, known as the “receptacle.” This is best seen in Cysticercus cellulosæ, in which there is also a very characteristic bend or kink in the pedicle of invagination, which in most other bladder-worms remains straight (see fig. 2, C) . ”

“ It has been generally assumed that echinococcus fluid contains a toxic substance the escape of which into the body cavity (at operation or by bursting of a hydatid cyst) produces more or less severe symptoms (fever, peritonitis, urticaria) , so much so that one speaks of hydatid intoxication. The investigations of Kobert, Joest, etc., have, however, shown the harmlessness of fresh undecomposed hydatid and cysticercus fluid for rabbits, mice and guinea-pigs, whether inoculated intraperitoneally, subcutaneously or intravenously. ”

“ The dangers too of the parasite being conveyed by the cook’s unwashed hands to the plates in which meals are served, and the common practice of using the same knife for cutting up meat, and afterwards, without washing it, for other culinary purposes, must not be overlooked. With good selection and careful feeding there seems to be every probability that Cysticercus would soon almost or completely disappear from our Commissariat cattle. If they were entirely stall-fed and watered from wells there could scarcely be a possibility of infection after their purchase. ”

“ The parasite, of course, robs its host, but usually in a scanty and sparing manner, and the injuries it inflicts can hardly be taken into account. There are, however, numerous cases4 in which the situation of the parasites or the nature of their food, added to their number and movements, may cause more or less injury, and even threaten the life of the host. It stands to reason that a Cysticercus cellulosæ situated in the skin is of but slight importance, whereas one that has penetrated the eye or the brain must give rise to serious disorders. ”