Metabolite pattern ofCysticercus cellulosaemetacestode from different predilection sites of swine using proton magnetic resonance spectroscopy

Cysticercosis due to Taenia solium is one of the most common public health problems in various regions of the world. We have performed prolon magnetic resonance spectroscopy (1H MRS) experiments of the fluid aspirated from cysticerci excised from skeletal muscle (n = 16) and brain (n = 9) of infected swine to compare the metabolite pattern of cysticerci in different predilection sites. Perchloric acid extract of cysticercus cysts excised from skeletal muscles (n = 16) was also prepared to ascertain water-soluble, low molecular weight metabolites using 1H MRS. Absolute quantification and statistical analysis of different metabolites was done to look for any significant differences in different locations of cysts. The metabolite pattern of cysticerci was found to be similar in the various predilection sites. Metabolites observed were leucine, valine, alanine, lysine, glycine, lipid contents, lactate, glutamate, acetate, succinate, creatine, choline, and glucose. Concentration of creatine in cysticercus fluid of cysts removed from the muscle was found to be significantly higher (p = 0.001) than the cysts located in the brain. We conclude that the metabolite pattern in the cysticerci is not influenced by the surrounding tissue location; however concentration of certain metabolites may depend upon the tissue location.

[In vitro effect of the S3Pvac vaccine against cysticercosis in human mononucleate cells]

INTRODUCTION

Neurocysticercosis (NCC) is a parasitic infection caused by the establishment of Taenia solium cysticerci in the central nervous system. The larval stage of the parasite also affects the pig, which is the essential intermediate host for transmission. For this reason, many researchers have focused on identifying protective antigens to prevent swine cysticercosis and interrupt the transmission. These include S3Pvac vaccine antigens. Vaccine is constituted by three protective synthetic peptides: KETc1, KETc12 and GK1. AIM. To evaluate the effect of the vaccine peptides KETc1, KETc12 and GK1 in mononuclear cells of patients with neuro-cysticercosis and healthy individuals.

SUBJECTS AND METHODS

Comparative, prospective, transverse study. We studied the proliferation and cytokine profile induced by the three peptides in mononuclear cells from three patients with active NCC, 16 patients by calcified NCC and 16 healthy subjects.

RESULTS

KETc1 induces low levels of proliferation in cells from patients with active and controlled NCC, both in lymphocytes and in monocytes. KETc12 and GK-1 induce positive proliferation levels of monocytes in healthy subjects.

CONCLUSIONS

KETc1 peptide could be used as an adjuvant in the treatment of patients with active NCC, as induced a Th2 response also GK1 peptide as stimulator of monocyte/macrophage in immunizations with other proteins.

Cysteine proteinase inhibitors in murine cysticercosis

We explored the prophylactic efficacies of two novel protease inhibitors in murine cysticercosis. Our results demonstrated a 95% and 80% reduction in parasite burden for mice injected with Z-LLL-FMK and Z-LLY-FMK, respectively. Further studies are merited on the role of cysteine proteinase inhibitors in treatment of cysticercosis.

Prediction of viability of porcine neurocysticercosis with proton magnetic resonance spectroscopy: correlation with histopathology

Neurocysticercosis (NCC) is the most frequent parasitic disease of central nervous system. In our earlier study, we had observed creatine [(creatine + phosphocreatine); (tCr)] on ex vivo proton MR spectroscopy (1H MRS) in some of the cysticercus cyst fluid samples obtained from swine's brain parenchyma. In current study, swine brains of freshly slaughtered animals naturally infected with NCC were subjected to ex vivo magnetic resonance (MR) imaging on a 1.5Tesla MR system. Cysticercus cysts (n = 12) were removed from these brains and were labeled depending upon presence or absence of edema around cysts as observed on imaging. Cysticercus cyst fluid (100 microl) was subjected to different 1H MRS experiments and results were compared with histopathological examinations to look for any relationship between tCr and parameters like quantification of musculature, and cellular infiltration in wall of the parasite. Histopathology of cyst wall was categorized into two groups based on cellular characteristics and the amount of musculature. Grade I cysts (n = 5) with no or minimal inflammation and large amount of musculature showed tCr on 1H MRS. However, grade II cysts (n = 7) with profuse inflammation and less amount of musculature in the cyst wall lacked tCr. Higher amount of musculature in grade I cysts was associated with higher concentration of tCr in the cyst fluid (r2 = 0.93, P = 0.007). Creatine appears to be a marker of innocuous and viable NCC.

Ultrastructural observations on the formation and metabolism of calcareous corpuscles in Cysticercus cellulosae

AIM

To study the formation and metabolism of calcareous corpuscles from Cysticercus cellulosae at the ultrastructure level.

METHODS

Transmission electron microscopy.

RESULTS

The developmental processes of calcareous corpuscles could be divided into two stages: the intracellular formation stage and the extracellular metabolic stage. The calcareous corpuscles were formed in a cell which we named calcareous corpuscle forming cell. At the early stage of the formation, the corpuscles appeared to be secretory granules in the cells. With the development of the corpuscles, they became bead-shaped and lamellae-like, then the calcareous corpuscle forming cell enlarged and the organellae degenerated. Finally the corpuscles gathered to form particle substances with black dense background, while the nucleus and organellae of the forming cell all disappeared. There were 1-3 or 10-20 calcareous corpuscles in a mature forming cell. Then, the corpuscles were released to the parenchymal tissues and gradually appeared to be concentric lamella or an empty cavity during the metabolic process.

CONCLUSION

The calcareous corpuscles were formed in calcareous corpuscle forming cell and consumed in metabolic process in the parenchymal layer of Cysticercus cellulosae.

[Establishment of Hymenolepis diminuta-animal model and morphology of cysticercoid]

AIM

To observe the morphological changes in the process of the development of Hymenolepis diminuta.

METHODS

The life cycle of Hymenolepis diminuta was established between Rattus domesticus albus and Triboliun castaneum. The morphology of cysticercoid were observed microscopically, and the ultrastructure of the body surface of cysticercoid were observed by scanning electron microscopy.

RESULTS

Three phases including the mature stage, the blister stage and the protective outer membrane-forming stage during the growing course of cysticercoid were observed microscopically. Under scanning electron microscope, lots of sieve-like micropores on the surface of mature cysticercoid were seen in the second week after infection. The blister phase was found in the third week and the outer membrane measuring about 45 microns in thickness were found surrounding the cysticercoid and vesicular surface, forming a smooth cyst wall in the fourth week.

CONCLUSION

The life cycle of Hymenolepis diminuta has been established in the animal-model. The finding of the three phases during the growing course of cysticercoid is reported for the first time.

[Histological changes of Cysticercus cellulosae under the action of proteinase of Omphalia lapidescens in vitro]

AIM

For the purpose of finding an anthelmintic with high efficacy, low toxicity and low cost, especially from the Chinese traditional medicines.

METHODS

Forty Cysticercus cellulosae were separately incubated with proteinase from artificially fermented Omphalia lapidescens for 2 h, 4 h and 8 h, and then examined for histological changes by light microscopy and compared with those of proteinase from natural dry Omphalia lapidescens after similar treatment.

RESULTS

Cysticercus cellulosae were morphologically and structurally impaired after exposure to the action of proteinase of Omphalia lapidescens, and the degree of impairment was proportionally paralleled to the duration of treatment.

CONCLUSION

The anti-cysticercus effect of proteinase of Omphalia lapidescens and the homogeneity of proteinases from artificially fermented and natural Omphalia lapidescens were confirmed.

Experimental studies on physiological and morphological aspects of Cysticercus cellulosae in pigs

Three Small-Ear-Miniature, 3 Landrace-Small-Ear-Miniature, and one Douc-Yorkshire-Landrace pigs were inoculated orally with 100 000 eggs of Zhengzhou strain or 10 000 eggs of Harbin strain of Taenia solium. A total of 3739 cysticerci were recovered from 3 Small-Ear-Miniature and 3 Landrace-Small-Ear-Miniature pigs, giving an infection rate of 85.7% and a cysticercus recovery rate of 1.1%. The predilection sites of Cysticercus cellulosae in descending order were leg muscles, abdominal muscles, thoracic muscles, liver, head muscles, diaphragm, tongue, heart, trachea, and omentum/testes. Except 2 calcified cysticerci in the tongue, 2 in the heart, and 176 in the liver, the remaining cysticerci were all alive. The greatest number of cysticerci per 100 g of muscles or viscera was found in the head muscles, followed by the leg, diaphragm, heart, tongue, thoracic, abdominal, omentum, testes, and trachea. All cysticerci were evaginated in pig's bile after fluid was drawn out from cysticerci, whereas evagination occurred in only 83.2% of those without fluid drawing. In 364 evaginated cysticerci, the mean length and width of scolex, proglottid, and bladder, and diameter of rostellum and sucker were 826 x 747 microm, 5,370 x 1,734 microm, 2,885 x 3,002 microm, 155 microm, and 253 microm, respectively. In the protoscolex, the mean number of segments was 33. Each cysticercus had 2 rows of rostellar hooks on the scolex, and the mean length and width of inner and outer hooks were 151 x 18 microm and 117 x 14 microm, respectively. The number of paired hooks ranged from 10 to 18.

Cytomorphological spectrum of cysticercosis--a review of 132 cases

A retrospective analysis of fine needle aspirates of 132 cases of cysticercosis presenting as palpable nodule is presented. In 98 cases, larval parts, detached hooklets and scolex established the diagnosis; in another 24 cases, the background inflammatory pattern was helpful in suggesting the diagnosis of a parasitic lesion.

Formation of calcareous corpuscles in the lumen of excretory canals of Taenia solium cysticerci

Platyhelminths, like many other organisms, are capable of producing mineral concretions. In cestodes these are referred to as calcareous corpuscles. Studies on these concretions in different cestodes both in vivo and in vitro have resulted in a number of hypotheses on their origin, formation, and structure. Calcareous corpuscles are believed to be of cellular origin, although the kind of cell involved and the mechanisms of mineralization remain under discussion. In the present paper we show that formation of calcareous corpuscles in cysticerci of Taenia solium is not of intracellular origin, as described for other cestodes, but occurs extracellularly in the lumen of protonephridial ducts in a way similar to that proposed for trematodes. This finding enhances the function of the protonephridial ducts, at least in the larvae of T. solium, to the roles formerly ascribed to the calcareous corpuscles.

Observations on the effects of cysticercosis immune sera on cysticercosis by scanning electronmicroscopy

Two antigens of Taenia solium cysticercus, cystic fluid antigen (CFA) and the culture medium antigen (CMA), were used respectively to immunize rabbits in order to obtain immunosera. The CMA immunoserum added to culture medium with cysticerci limited the activities of the bladder worms. By using the scanning electronmicroscope, we could observe particulate deposits on the surface of the scolices, suckers and necks of the worms. The CFA immunoserum group showed similar changes but the deposit was less than that on the worms in the former group and appeared mainly on the cystic wall. After adding complement to the two groups mentioned above, we found that the microcilia on the surface of the worms were swollen and were seriously damaged. The worms treated with praziquantel were damaged over large area of their surfaces and were affected deep into their tissues. The damaged parts of the worms were quite different between the two groups. CMA is secreted by the living worms and therefore the serum antibodies are more effective than CFA in anti-parasite activity.

A method for the isolation of tegument syncytium mitochondria from Taenia crassiceps cysticerci and partial characterization of their aerobic metabolism

Heterogeneous populations of mitochondria have been described in helminths. Mitochondria from different tissues have been isolated in adult organisms. However, in larvae, due to their small size, isolation from tissues has not been feasible. A method for the isolation of tegumental mitochondria from the larval stage of Taenia crassiceps is described. After solubilization of the plasma membrane with saponin, tegumental mitochondria were purified by a simple and rapid protocol of differential centrifugation, which allowed the retention of suitable quantities of well-preserved mitochondria, as judged by biochemical and ultrastructural parameters. Respiratory activity evoked by exogenous NADH was negligible, but its oxidation increased several-fold after sonication of intact mitochondria. Other substrates, e.g., succinate and malate-glutamate, were oxidized at high rate, leading to the formation of a H+ gradient across the inner mitochondrial membrane, which, in turn, supported oxidative phosphorylation. These results indicate that tegumental mitochondria carry out aerobic metabolism.

Demonstration of Taenia crassiceps cysteine proteinase activity in tegumentary lysosome-like vesicles

Larval stages of Taenia species survive for prolonged periods in the tissues of their intermediate hosts. Other groups have demonstrated that host immunoglobulins are taken up by the cysticerci by adsorptive endocytosis, degraded, and the amino acids incorporated into parasite proteins. We have shown that a 43-kDa cysteine proteinase is the major parasite enzyme that degrades immunoglobulin in vitro. To localize this enzyme in situ, Taenia crassiceps cysticerci were incubated with the peptide substrate Z-Phe-Arg-methoxynaphthylamide. Free methoxynaphthylamide was coupled to p-rosanilin and osmium and visualized by transmission electron microscopy. Initial studies of cysticerci incubated without substrate confirmed the normal microanatomy and absence of significant host inflammation. In comparison to controls with no substrate, sections of cysticerci incubated with substrate revealed electron-dense deposits in round vesicles. The vesicles were found primarily within the tegumentary cytons and internuncial processes, a location similar to that described for vesicles associated with adsorptive endocytosis. There were proportionately more endocytotic vesicles and electron-dense vesicles in smaller cysticerci than larger ones. Formation of electron-dense deposits was inhibited by heat and partially inhibited by the cysteine proteinase inhibitor E-64. These data are consistent with localization of the cysteine proteinase activity to lysosome-like vesicles.

Impairment of the inflammatory reaction on implanted Taenia solium metacestodes in mice by a T. solium RNA-peptide: a scanning electron microscopy study

Inhibition of inflammation by a Taenia solium RNA-peptide (metacestode factor, MF) was studied by scanning electron microscopy (SEM). Viable (96%) T. solium metacestodes obtained from a naturally infected pig were dissected and implanted in treated and control mice, removed at 6 and 12 days postimplantation (p.i.), and studied by SEM. At day 6, metacestodes in control mice showed vigorous inflammation, whereas in mice treated with MF they were apparently intact with exiguous inflammation. Mice immunized with T. solium metacestode antigens showed a moderate inflammation; those treated with both MF and T. solium antigens presented scanty inflammation. At day 12, metacestodes presented copious inflammation and severe damage to the sucker tissues in mice immunized with T. solium; in mice treated with either MF or MF and T. solium antigens there was only discrete inflammation. These observations illustrate the central role of MF in the inhibition of the early events leading to the parasite's destruction by means of an inflammatory response.

Ultrastructural observation on spermatocytogenesis in Taeniid cestodes

AIM

To study the spermatocytogenesis of taeniid cestodes at the ultrastructural leaves.

METHODS

Transmission electron microscopy.

RESULTS

The ultrastructural observation on spermatocytogenesis in Taenia solium, T. saginata and T. pisiformis were made by TEM. Two types of spermatogonia; type A and B, as well as the supporting cells surrounding the peripheral of spermatogonia are recognized. The type A spermatogonia are stem cells and the type B are mother cells which produce 16 primary spermatocytes by mitosis for 4 times with the cells unseparated. The primary spermatocytes are characterized by the ribosome masses in the cytoplasm. 32 secondary spermatocytes arranged in roselike were produced by reductive division of primary spermatocytes. The secondary spermatocytes become the spermatid quickly by short time development.

CONCLUSION

The dividing mode of spermatogonia in Taeniid cestodes is mitosis with cells unseparated.

[Electron microscopic observation on cysticercus cellulosae treated with mienangling in vitro]

OBJECTIVE

To observe the effect of Mienangling (MNL) in treating cysticercus cellulosae in vitro.

METHODS

The changes of cysticercus cellulosae treated in vitro with the MNL extracts, praziquantel (PQT) and albendazole (ALB) were studied under the transmission and scanning electron microscopes.

RESULTS

Under the scanning electron microscope, the authors can see that all of the cysticercus's scoleces did not grow in the MNL and PQT groups, cyst walls shrivelled, tegument's ectoplasts were damaged, microtriches's ultrastructures were not clear or exfoliated, some corpuscular matter densely was distributed in the surface; 46.7% of cysticercus cellulosaes in the ALB group had been excystated, the rostellar hooks of rostella developed normally, four sucker's surface wrer hollow, the necks were eroded, and grooves of sonite disappeared. Under the transmission electron microscope, we can see that the tegument, basement membrane, muscular layer and parenchyma in the groups of MNL and PQT were all clearly damaged, but the harmful effect of MNL to parenchyma's nerve cords is more serious than the PQT. The damage of all layers of the cysticercus cellulosae in the ALB group is smaller in degree than the MNL and the PQT.

CONCLUSION

The MNL has marked damaging effect to cysticercus cellulosae.

Purification and ultrastructural localization of surface glycoproteins of Taenia solium (Cestoda) cysticerci

A glycoprotein-enriched fraction was obtained by Concanavalin A-Sepharose 4B affinity chromatography from a crude extract of T. solium cysticerci. The six most prominent glycoproteins with molecular sizes of 180, 103, 96, 68, 55 and 45 kDa were purified by electro-elution from polyacrylamide gel slices. Ultrastructural localization assays using hyperimmune rabbit sera to each glycoprotein, demonstrated their presence on the tegumentary surface of the bladder wall of T. solium cysticerci. Similar studies showed that the 180 kDa glycoprotein is also present on the surface of the T. solium and T. saginata adult worms, as well as in T. saginata, T. pisiformis and T. crassiceps cysticerci. The 55 kDa glycoprotein, which is one of the most abundant on the cyst surface, was found to correspond to the heavy chain of pig IgG by Western blotting.

Twinning in metacestodes of Taenia solium

Two cysticerci containing 2 scolices were found among several thousand Taenia solium metacestodes dissected from swine. Microscopic study of tissue sections revealed that both worms were equally well developed in 1 bladder worm, whereas 1 member of the other pair was incompletely formed.

Neuroanatomy of Cysticercus cellulosae (Cestoda) as revealed by acetylcholinesterase and nonspecific esterase histochemistry

The nervous system of Cysticercus cellulosae, the metacestode stage of the tapeworm Taenia solium, was delineated using histochemical methods for the localization of the enzyme markers; nonspecific esterase and acetylcholinesterase. The main features of the nervous system include a pair of cerebral ganglia, a circumcerebral nerve ring, a rostellar nerve ring, and anterior and posterior nerves and their branches. The posterior nerves form a subtegumental network in the strobila and the bladder wall. A nerve network around excretory tubules could also be demonstrated, suggesting neuronal control of excretion in the metacestode. No sheath was observed around the nervous system. The morphological features described suggest "cephalization" of the nervous system in this parasite.

Cysticerci (Cestoda: Taeniidae) from white-tailed deer, Odocoileus virginianus, in southern Florida

Metacestodes (cysticerci) of Taenia omissa Lühe, 1910, and Taenia hydatigena Pallas, 1776, were found in 9 and 1 of 124 white-tailed deer, respectively, in southern Florida in 1984-1986. Intensities of T. omissa varied from 1 to 15 (mean = 4.6); only 1 cysticercus of T. hydatigena was collected. No significant difference in the prevalences of T. omissa according to sex, age, or locality was observed.

Methyl 5(6)-(alpha-hydroxyphenyl methyl) benzimidazole-2-carbamate and cysticercosis: chemotherapeutic and electron microscopic studies

Methyl 5(6)-(alpha-hydroxyphenyl methyl) benzimidazole-2-carbamate, a major metabolite of mebendazole was evaluated against Cysticercus fasciolaria (larval form of Taenia taeniaeformis) in rats. The metabolite was assessed in various doses. A regimen of 50 mg/kg x 10 (ip), given one day apart, was found to be most effective and killed all the mature cysticerci. On developing cysts, the treatment was initiated in two schedules; 5 days prior to (d-5 to d-1) and 5 days after (d + 6 to d + 10) administration of T. taeniaeformis eggs to rats. The later protocol with 100 mg/kg x 5 dose (ip) resulted in 95% inhibition in the establishment of cysticerci. Activity of mebendazole against mature cysts was parallel to metabolite whereas against developing cysts, it was inferior. The time related topographical changes that occurred in mature C. fasciolaris after treatment with metabolite (50 mg/kg x 10, ip, one day apart) were observed by scanning electron microscopy. There was loss of contractivity, gradual disappearance of microtriches and progressive degeneration of tegument. Similar changes were noticed with mebendazole. The possession of better efficacy and higher safety range [Indian J Exp. Biol, 25 (1987) 871], suggests that the metabolite can be a potential anthelmintic for man and animals.

[5 cases of cysticercosis in Rwanda]

Five cases of cysticercosis are reported. They were diagnosed by microscopic examination of the sub-cutaneous nodules in which T. Solium larvae were found. Results of the treatment by Praziquantel are reported, with regard to the symptomatology of the patients after one year of observation. Necrosis of cysticerci larvae few month after starting the treatment was observed in three cases by microscopical anatomy test. Three doses of Praziquantel of 20 mg/kg at four hours of interval are efficient against sub-cutaneous and muscular cysticercosis. Such a treatment presents the advantage very important in some rural zones in Africa, of a single dose in one day.

Host response in childhood neurocysticercosis. Some pathological aspects

The autopsy findings in 18 cases of childhood neurocysticercosis are described. Twelve of the children had died from other causes. Asymptomatic disease correlated with immunodeficiency and with negative serum anticysticercosis antibody test.

Taenia crassiceps: basic mechanisms of endocytosis in the cysticercus

The effects of glucose, yeast extract, fetal bovine serum albumin, and ruthenium red on endocytosis of smooth micropinocytotic vesicles (pinosomes) in the tegument of the cysticercus of Taenia crassiceps have been investigated stereologically. Glucose has been shown to stimulate pinocytosis, whether it was used alone or in combination with yeast extract or bovine serum albumin. Yeast extract was a stimulant of endocytosis. Bovine serum albumin was the most potent stimulant of all the substances investigated in this study. Although the time of incubation in ruthenium red was the same for all incubation experiments, varied numbers of ruthenium red-containing pinosomes were observed in different experiments. The role of ruthenium red as a stimulant and/or initiator of endocytosis and the possible explanations for differences in ruthenium red uptake are discussed.

Taenia crassiceps: temperature, polycations, polyanions, and cysticercal endocytosis

The effect of various temperatures, poly-L-lysine, and poly-L-glutamic acid on endocytosis of smooth micropinocytotic vesicles (pinosomes) in the tegument of the cysticercus of Taenia crassiceps has been investigated stereologically. The temperature regimes used were 0, 5, 10, 20, 30, and 40 C. Maximum volume, surface density, and number per unit volume were found at 40 C, and minimum surface-to-volume ratio and numbers at 10 C. At 10 C, mean pinosome volume and mean surface area per pinosome were maximal, but volume and surface density did not differ significantly from 40 C. It is proposed that this anomalous finding for 10 C incubations was due to this being a critical temperature at which a slower rate of pinosome formation was compensated for by the formation of larger individual pinosomes. Poly-L-lysine was shown to be a stimulant of pinosome formation, leading to a significant increase in numbers per unit volume. However, volume and surface density, surface-to-volume ratio, mean volume, and mean surface area per pinosome were not significantly different in poly-L-lysine-incubated samples, when compared to controls (fresh from the mouse) or incubations in medium only or samples returned to medium after poly-L-lysine incubation, the only exception being surface to volume ratio and mean volume of pinosomes in the 75-min incubation. These anomalous results were explained by a marked reduction in the form ellipse values, which indicated the production of more elliptical-shaped pinosomes under poly-L-lysine stimulation. Incubation in poly-L-glutamine acid did not have any significant effect at any incubation time.

[Fine structure of the bladder tegument of Taenia saginata metacercaria with reference to establishment in the final host]

The ultrastructure of the bladder tegument of the metacestode of Taenia saginata, with considerations on the establishment in the definitive host. The tegument surface of invaginated Taenia saginata metacestodes was demonstrated by scanning electron micrograph. The tegument is folded irregularly and its surface is amplified by the presence of microtriches, 44-45 microtriches/micron 2. The microtriches are about 500 nm long and have an absorptive function. Likely, form and sensity of microtriches turn out a capillary attraction that plays an important role in contact with surface (finger, tongue and duodenum of man, instrumentarium , glass, plastics). This opinion is supported by scanning electron micrograph of the surface of finger-tips, of the tongue and the duodenum of man.

Electron microscopic observations of intravitreal Cysticercus cellulosae (Taenia solium)

Cysticercus cellulosae, the larval stage of Taenia solium, was studied by light and electron microscopy after its removal from the vitreous. The ultrastructure of the larva is highly organized and displays a superficial tegument and deeper parenchyma. The tegument contains a microvillous surface overlying a syncytial cytoplasm. A deeper muscular layer overlies the parenchyma, within which are highly specialized structures important in water balance, flame cells, and acid-neutralizing calcareous corpuscles.

Intraocular cysticercosis

Two intravitreal Taenia cysts were removed intact by pars plana vitrectomy from a 59-year-old woman who had never left the continental United States. The intraocular course of the cysts progressed from an initial chorioretinal location, accompanied by an intense focal inflammatory reaction, to free floating in the vitreous cavity within two months; thereafter, there was only a low-grade vitritis for an additional five months until removal. Light and electron microscopic studies suggested Cysticercus cellulosae as the infecting agent, although mature hooklets were absent. Local pork products were considered to be the source of the infection. Preretinal fibrosis and posterior subcapsular vacuoles were the final residua and did not progress after removal of the cysts. Although uncommon in the United States, cysticercosis should be considered in cases of focal necrotizing chorioretinitis.

[1st report of an intermediary host of Moniezia sp in Cuba]

The determination of an oribatid belonging to the Scheloribates genus as an intermediary host of the Moniezia sp. helminth is reported for the first time in Cuba. Photographs and measurements taken during the infecting larval state of Moniezia (cisticercoid) found are included, such as it is observed because of transparency in the interior of acarus and drew out from the Latter for its better identification.

Scanning electron microscopic observations of Cysticercus fasciolaris (=Taenia taeniaeformis) after treatment of mice with mebendazole

The time-related topographical changes in mature cysticerci of Taenia taeniaformis induced after medication of infected mice with 250 ppm of mebendazole are described. The changes included the gradual disappearance of microtriches and progressive degeneration of the tegment resulting in an irregular surface with grooves, holes, and craterlike structures. Host cells adhered to the altered areas and the number of these cells increased when more severe changes became apparent. Finally the necrotized cysticerci, which lost their tegument completely, were almost entirely covered with adhesive host cells. A difference in the time sequence of the reported changes occurred between the scolex, the pseudoproglottids, and the bladder. This difference in susceptibility towards the drug between the three parts of the parasite in relation to the morphology of their microtrichous covering is discussed.

Morphological changes in cysticerci of Taenia taeniaeformis after mebendazole treatment

The progressive micromorphological changes in Taenia taeniaeformis cysticerci, induced by a single parenteral treatment of the infected mice with mebendazole, are described. The time-related alterations concerned the tegument and tegumental cells and were successively: disappearance of microtubules, accumulation of secretory substances in the Golgi areas, decrease in number to complete loss of microtriches, "ballooning" of all tegumental cells with subsequent burst, vacuolization and degeneration of the tegument, and finally necrosis of the pseudoproglottids. Similar but less pronounced injuries were seen in the scolices, although microtubules disappeared as early as in the pseudoproglottids. Microtubules from the host tissues remained intact. The meaning of the apparent primary interference of mebendazole with the microtubular system in relation to the subsequently observed death of the cysticercoids is discussed.