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Morphological parameters of the cestode Proteocephalus percae which is common parasite of a perch were studied in four water bodies of Karelia. Significant morphological variability was observed within populations of the parasite. The phenotypic structure of certain populations of parasite is complicated and differs one population from another.
Twenty-two of 26 white-throated sparrows, Zonotrichia albicollis, from Algonquin Park, Ontario, Canada, hosted 1 or 2 species of platyhelminths. One species of cestode and 3 of digeneans were collected. Anonchotaenia quiscali inhabited 50% of the sparrows. This is the third report of A. quiscali; Z. albicollis is a new host. Brachylecithum nanum inhabited 43%, Zonorchis alveyi 15%, and Prosthogonimus macrorchis 8% of the sparrows examined. Ontario is a new geographic distribution record from all 4 parasite species. The proportion of hosts infected with 2 species was not significantly different from expected based on single species prevalences, indicating that there is no competitive interaction among these species of parasites for access to the avian hosts.
OBJECTIVE: To investigate whether targeted chemotherapy can reduce parasite prevalence rates in rural black preschool children. DESIGN: The study consisted of a before/after trial. Stool and urine samples were analysed on four occasions over a 21-week period. SETTING: Crèches in two rural areas of southern KwaZulu/Natal (coastal and inland). PATIENTS: Two hundred children of 4-6 years of age attending 19 crèches in the area. INTERVENTION: Targeted chemotherapy using albendazole for nematode infestations, praziquantel for trematode and cestode infestations and metronidazole for protozoal infections was administered twice at an interval of 14 weeks. MAIN OUTCOME MEASURE: Prevalence rates. RESULTS: The prevalence of Ascaris lumbricoides, Trichuris trichiura and Necator americanus infestation decreased significantly after treatment. Reinfestation rates 12 weeks after treatment were 16% for A. lumbricoides, 33% for T. trichiura, 24% for Giardia lamblia and 3% for N. americanus. No reinfestation was noted for Schistosoma haematobium, Hymenolepsis or Taenia species. CONCLUSION: The study suggests that parasite prevalence rates in children can be reduced by the administration of appropriate chemotherapy at regular intervals. However, the provision of clean water and adequate sewerage facilities remains a high priority for black communities living in rural areas of South Africa.
Phoreiobothrium manirei n. sp. is described from the spiral intestines of 3 immature individuals of the great hammerhead shark Sphyrna mokarran collected off of the west coast of Florida. This cestode is unusual in that it possesses 4 muscular papillae on the anterior margin of the accessory sucker. Numerous small protrusions with central cilium-like projections were conspicuous throughout the posterior margin of each bothridium. This species possesses the unique combination of bothridia posteriorly subdivided into subloculi and hooks with extended bases and 2 rather than 3 prongs. In fact, the hooks are strikingly like those of species in the genera Dicranobothrium and Platybothrium. This combination of characters suggests that the bifid hook condition is plesiomorphic with respect to the trifid hook condition within the Onchobothriidae. These data further suggest that the triloculated bothridial condition is plesiomorphic relative to the biloculated condition.
This paper represents the first documentation and description of Pachysentis canicola cystacanths and the first report of a Pachysentis sp. in a paratenic reptile from the Americas. The western diamondback rattlesnake (Crotalus atrox) is also listed as a new host for tetrathyridia of the cyclophyllidean cestode (Mesocestoides sp.) and for the cystacanths of the oligacanthoryhynchid acanthocephalan (P. canicola). Six rattlesnake specimens were examined from Nolan County (32.30 degrees N, 100.39 degrees W), Texas. Four snakes (67%) were found parasitized with between 3 and 16 (mean 7) encapsulated tetrathyridia and 1 host additionally was infected with 6 P. canicola cystacanths within its mesentery.
A new cestode, Echinobothrium notoguidoi n. sp., is described from the spiral intestine of the shark Mustelus schmitti, from coastal waters off Mar del Plata, Argentina. This species is distinguished from all others in the genus by a rostellar armature consisting of 2 apical groups of 31 large hooks each, arranged in 2 rows (16 anterior, 15 posterior) with 13 hooklets per side, a wide corona of 8-11 rows of spines posterior to the rostellum, 8 rows of 24-26 spines on the cephalic peduncle, and 11-15 testes per proglottid. The new species most closely resembles 2 congeners that also parasitize sharks, Echinobothrium musteli and Echinobothrium scoliodoni, on the basis of the armature of the rostellum and cephalic peduncle and the presence of a corona of small spines. Echinobothrium notoguidoi can be differentiated from E. musteli by the number of hooklets (3) and testes (22), and from E. scoliodoni by the number of large hooks (10-13), spines on the cephalic peduncle (> 100), and segments (40-50). Echinobothrium notoguidoi is clearly distinguished from Echinobothrium pigmentatum described previously from Zapteryx brevirostris in Argentine waters by the following combination of characters: corona of hooks lacking, possession of fewer apical hooks (20), hooklets in a continuous row instead of separate groups, fewer spines in the cephalic peduncle (9-13 per row), and fewer testes (5-7) per proglottid.
Postlarvae of the cestode Hepatoxylon trichiuri (Holten, 1802) were found attached to the surface of viscera of Prionace glauca (Linnaeus, 1758) taken from Atlantic coastal waters off the south coast of Massachusetts, USA. Gross anatomy of the attachment site shows a quadripartite rim surrounding a deep pit with holes corresponding to the penetration site of each tentacle. Hyperplasia of the liver capsule into outgrowths at the attachment site conform to the attachment of the bothridia. The cuboidal epithelium of the liver capsule became columnar forming papillary outgrowths, with a dense fibrotic reaction beneath the attachment site and infiltration by leukocytes and pigment containing granulocytic cells. Blood sinusoids beneath the attachment site are greatly enlarged. Postlarvae attached to the surface of the epigonal organs of three blue sharks were not accompanied by reactions. SEM examination of the scolex of H. trichiuri postlarvae revealed fused pairs of bothridia within infolded muscular lateral rims, porose tegument devoid of microtriches and a bilateral plane of symmetry in the tentacular armature.
Component helminth communities of Aneides lugubris (N=31), Batrachoseps nigriventris (N=63), Ensatina eschscholtzii (N=30), and Taricha torosa (N=68) from California were determined. The compound helminth community consisted of 1 species of cestode, Bitegmen gerrhonoti and 6 species of nematodes, Batracholandros salamandrae, Cosmocercoides variabilis, Falcaustra pretiosa, Megalobatrachonema gigantica, Oswaldocruzia pipiens, and Rhabdias joaquinensis. The least diverse infracommunities were associated with Batrachoseps nigriventris while T. torosa had the most diverse fauna. Only B. salamandrae occurred in each of the 4 component communities. Each of the other helminth species was harbored by a single host species. New host records for B. salamandrae in B. nigriventris and T. torosa; O. pipiens in A. lugubris; C. variabilis in E. eschscholtzii; F. pretiosa and M. gigantica in T. torosa are established.
Cestodosis in battery-housed laying hens severely reduced egg production particularly at the time of peak production. Hens were able to consume large numbers of Musca domestica, the intermediate host of Choanotaenia infundibulum following the use of an aerosol insecticide to control flies. A considerable discharge of cestodes followed the use of "Lintex" in the feed resulting in a marked improvement in egg production. The use of an insect growth regulator in the feed showed promise in controlling the breeding of flies.
A 56-year-old woman from southwestern Minnesota underwent an extended left hepatic lobectomy to remove a large multinodular mass with a necrotic central cavity. The clinical, serological, and pathological findings led to the diagnosis of alveolar hydatid disease, and specific identification of Echinococcus multilocularis was achieved by growing mature larvas in voles inoculated intraperitoneally with tissue from the hepatic lesions. The patient probably acquired her infection some years previously from pet cats or dogs that had become infected by ingesting infected rodents. In North America E multilocularis is enzootic in the northern tundra zone of Alaska and Canada. Since 1964 the cestode has been recognized with increasing frequency in several north-central states, including Minnesota. The parasite may extend its range farther south, since suitable animal hosts occur throughout the United States.
Luxabendazole (LBZ) is a new benzimidazole carbamate chemotherapeutic agent, which has proved to be very effective against adult and immature stages of the major gastrointestinal nematodes, trematodes and cestodes. While information on the efficacy of LBZ in several animal species is available, there seems to be no published information describing the disposition kinetics in any of them. As a part of the clinical development of luxabendazole, the pharmacokinetics of a single intravenous dose was investigated in parasite-free rabbits. Serial blood samples were collected at timed intervals for 12 h following administration of the dose, and concentrations in plasma were determined by a sensitive and specific HPLC method. Published data on LBZ point to the possible existence of an enterohepatic cycle (EHC), and so, it seemed appropriate to carry out two different forms of test. In the first, the possibility of intestinal reabsorption of LBZ excreted via the bile was allowed for (Treatment 1), while in the second it was interrupted by the oral administration of activated charcoal (Treatment 2). In both cases the animals were given a single dose of 10 mg kg-1 of LBZ intravenously (i.v). Comparison of the areas under the curve (AUCs) of LBZ concentrations in plasma samples taken from the animals receiving each treatment showed significant difference (p < 0.05). The given dose (10 mg kg-1) was converted in Treatment 1 to an effective dose of 13.9 mg kg-1 through recycling of LBZ. With Treatment 2 a bicompartmental distribution model for this drug was confirmed, together with high apparent distribution volumes: Vc = 1.87 L kg-1, and V beta = 7.09 L kg-1.
The surface of the filarial worm consists of an extracellular cuticle which overlies the outer plasma membrane of the hypodermis. The cuticle is permeable to a wide range of molecules of low molecular weight, and L-amino acid and D-glucose uptake occurs transcuticularly by active transport and diffusion in physiologically significant amounts. Transport mechanisms are associated with the plasma membrane of the hypodermis, and the cuticle may be considered an 'unstirred layer' distal to the transport loci. The outermost layer of the cuticle, or epicuticle, consists of a lipid bilayer which differs from a typical plasma membrane. There is no conclusive evidence for turnover of the epicuticular materials between the larval moults and in the adult stage. It is proposed that the filarial surface does not show the dynamic properties associated with the surface membranes of parasitic cestodes and trematodes.
The study of coprolites (desiccated feces) is recognized as a viable method for analyzing parasitism of prehistoric peoples. Eight species of helminth parasites, including nematodes, cestodes, and acanthcephalans, have been recovered from archaeological sites on the Colorado Plateau. The comparative analysis of parasitological findings illustrates the effects of changing subsistence strategies and varying life-style on prehistoric human parasitism. This comparative study is based on the analysis of coprolites recovered from one Archaic hunter-gatherer site and two Anasazi agricultural villages. Hunter-gatherers are represented by coprolites from Dust Devil Cave in south-eastern Utah. Coprolites of prehistoric agriculturalists from Antelope House in Canyon de Chelly, Arizona, and from Salmon Ruin in northwestern New Mexico were studied. The results demonstrate that helminth parasitism increased with the advent of agriculture. Between the agricultural sites, differences in patterns of excreta disposal, foraging behavior, and local ecology resulted in pronounced variations in both percentage of coprolites containing parasite remains and the number of parasite species represented.
The ubiquitous intracellular molecule myo-inositol hexakisphosphate (IP6) is present extracellularly in the hydatid cyst wall (HCW) of the parasitic cestode Echinococcus granulosus. This study shows that extracellular IP6 is present as its solid calcium salt, in the form of deposits that are observed, at the ultrastructural level, as naturally electron dense granules some tens of nanometers in diameter. The presence of a calcium salt of IP6 in these structures was determined by two different electron microscopy techniques: (i) the analysis of the spatial distribution of phosphorus and calcium in the outer, acellular layer of the HCW (the laminated layer, LL) through electron energy loss spectroscopy, and (ii) the observation, by transmission electron microscopy, of HCW that were selectively depleted of IP6 by treatment with EGTA or phytase, an enzyme that catalyses the dephosphorylation of IP6. The deposits of the IP6-Ca(II) salt are also observed inside membrane vesicles in cells of the germinal layer (the inner, cellular layer of the HCW), indicating that IP6 precipitates with calcium within a cellular vesicular compartment and is then secreted to the LL. Thus, much as in plants (that produce vesicular IP6 deposits), the existence of transporters for IP6 or its precursors in internal membranes is needed to explain the compound's cellular localisation in E. granulosus.
Echinococcus granulosus is a parasitic cestode causing hydatidosis in intermediate hosts (human and herbivorous). Most symptoms of the disease occur by the pressure exerted on viscera by cysts that are formed upon ingestion of the parasite eggs excreted by definitive hosts (canines). Protoscoleces, the developmental form of the parasite infective to definitive hosts, are formed in the germinal nucleated layer of fertile hydatid cysts. For unknown reasons, some cysts are unable to produce protoscoleces (infertile hydatid cysts). In this study, analysis of DNA fragmentation using TUNEL and agarose gel electrophoresis showed higher levels of apoptosis in infertile cysts as compared to fertile cysts. Additionally, caspase 3 was detected both in fertile and infertile cysts; the activity of this enzyme was found to be higher in infertile cysts. We conclude that apoptosis may be involved in hydatid cyst infertility. This is the first report on the presence of programmed cell death in E. granulosus.
We have developed a kit to diagnose hydatidosis, based on the detection of specific antibodies. This disease, caused by larvae of the cestode Echinococcus granulosus, is a zoonosis commonly found throughout the world. The diagnostic kit discriminates between positive and negative cases in a way that is easily interpreted, i.e., positive cases form a colored band on an inert substrate. The results show test sensitivity to be some 94.87% and specificity 85.71%, which is comparable to those of the ELISA technique. The high sensitivity and specificity of this test affords the great advantage of speed in diagnosing this parasitosis. No other equipment or procedure is required.
Many invertebrates accumulate propionate, or products derived from propionate, as products of fermentation. Evidence has been reported that the nematode, Ascaris suum, the cestode, Spirometra mansonoides, and the trematode, Fasciola hepatica, accumulate propionate by means of an adenosine triphosphate (ATP)-generating decarboxylation of succinate. To generate energy, an acyl coenzyme A (CoA) transferase that would transfer CoA to succinate is required as one component of the sequence of reactions. Recently, an acyl CoA transferase was isolated from Ascaris mitochondria and purified to electrophoretic homogeneity. However, upon examination of the substrate specificities of this enzyme, it was found essentially to lack the ability to use succinate or succinyl CoA as an acceptor or donor of CoA, respectively. Therefore, this transferase could not serve to activate succinate. This article describes the isolation of an additional acyl CoA transferase from Ascaris mitochondria that appears to be unique in its substrate specificity and that could easily account not only for the activation of succinate but also for the regulation of succinate metabolism primarily in the direction of decarboxylation to propionate. This is in contrast with mammalian tissues, which act in the opposite direction by catalyzing the fixation of CO2 into propionate, thereby forming succinate and accounting for the glycogenic nature of dietary propionate. Possible functions of the two acyl CoA transferases are discussed.
This study describes the synthesis of propargylic alcohols derived from isatin and their biochemical and morphological effects on Echinococcus multilocularis metacestodes in Meriones unguiculatus. Propargylic alcohols decreased the alkaline phosphatase and the lactate dehydrogenase activities of the metacestode selectively. The most effective compound, 1b, decreased the lactate dehydrogenase enzymatic activity, and the glucose concentration in the parasite increased, whereas the glycogen content was partially decreased. Furthermore, the ultrastructure study revealed several damages. The host-parasite relationships are very important in the intrahepatic cestodes as shown by the biochemical side effects observed in the host's liver during the treatment. An in vitro enzymatic study was performed with alcohols 1b and 1c.