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Neurocysticercosis in an Orthodox Jewish community in New York City.

BACKGROUND AND METHODS: From June 1990 through July 1991, intracerebral infection with the larval stage of the pork tapeworm Taenia solium was diagnosed in four unrelated persons in an Orthodox Jewish community in New York City. None of the patients had eaten pork, and only one had traveled to a country in which T. solium infection was endemic. We investigated this outbreak, screened serum samples from family members and household contacts for antibodies to cysticercosis, and examined stool specimens from household employees for eggs of taenia species. RESULTS: The four patients had recurrent seizures and brain lesions that were radiologically consistent with the presence of cysticerci. The diagnosis was confirmed in two patients by a brain biopsy, and in two by immunoblot assays for cysticercus antibodies. Of 17 immediate family members screened serologically, 7 from two families had cysticercus antibodies. Magnetic resonance imaging of the brain showed cystic lesions in two of the seropositive family members, one of whom had had a seizure. Examinations of six domestic employees from all four households revealed an active infection with taenia species in one and a positive serologic test in another. Since these women had recently emigrated from Latin American countries where T. solium infection is endemic, they were the most likely sources of infection in the members of these households. CONCLUSIONS: A diagnosis of neurocysticercosis should be considered in patients with seizures and radiologic evidence of cystic brain lesions, even in those who do not eat pork and who have not traveled to a country in which T. solium infection is endemic. Recent emigrants from countries in which T. solium infection is endemic should be screened for tapeworm infection in their stools before they are employed as housekeepers or food handlers.

Adolescent↗

Helminth parasites of wolves (Canis lupus): a species list and an analysis of published prevalence studies in Nearctic and Palaearctic populations.

A literature survey was undertaken in order to draw up a definitive list of helminth parasites of the wolf, Canis lupus. From 27 papers a total of 72 helminth species from 40 genera were recorded that infect wolves, of which 93% were identified from the gastrointestinal tract at necropsy. They comprised 28 species of nematode, 27 species of cestode, 16 species of trematode and one acanthocephalan. Of these, 46 species were able to be included in further meta-analysis of prevalence data derived from 25 publications for which the total number of wolves examined was 1282 (1066 from Nearctic populations, and 216 from the Palaearctic region). These two populations were further subdivided into three relevent ecosystems or biomes, i.e. temperate/montane (n=216), boreal (n=805) or tundra (n=261). The meta-analysis of relative prevalence indicated the most common helminth species to be the tapeworm Taenia hydatigena, which occurred at relative rates of >30% for either zoogeographic region as well as in each of the three biomes. The related tapeworm, Echinococcus granulosus also exhibited high meta-prevalence (>19%) in all host biomes. The hookworm Uncinaria stenocephala was the most prevalent nematode species by meta-analysis (meta-prevalence 44.9%) in the temperate/montane biome, while the ascarid Toxascaris leonina was the dominant helminth species (meta-prevalence 73.9%) in the tundra wolf populations. Trematodes in the genus Alaria were the dominant fluke (meta-prevalence 3-5%) in all biomes. Analysis of published studies for helminth biodiversity using the Shannon-Wiener index based on species number and meta-prevalence by region or biome, indicated that highest helminth diversity occurred in wolf populations of the temperate/ montane biome (Palaearctic), and was lowest in tundra wolf populations of the Nearctic (P<0.05). Helminth species assemblage in European wolf populations was therefore at least as great or more varied than was recorded for the larger less disturbed wolf populations of North America.

Animals↗

Cardiac hydatid cyst rupture as cause of death.

Echinococcosis is a frequent parasitic human infection in sheep-farming areas. It is caused by the larval or the cyst stage of a tapeworm, mainly Echinococcus granulosis. Humans can be infected by ingesting tapeworm eggs, from which cysts will be developed mostly in the liver and the lung. Cardiac involvement of echinococcosis is rare and its clinical evolution is silent till the complication stage. A young adult died suddenly. The autopsy showed a ruptured hydatid cyst hollowed on the right side of the interventricular septum, protruding in the ventricle. The left pulmonary artery contained white-colored fragments of a membrane, similar to the one found in the right ventricle, associated to small vesicles. All these elements were obstructing this vessel, extending to small pulmonary arterial branches. Dissection of the other organs did not show other locations. Microscopic examinations ascertained the diagnosis of echinococcosis. Death was imputed to a right ventricular hydatid cyst rupture with pulmonary artery embolism.

Abdominal Pain↗

Evolutionary implications of the adaptation to different immune systems in a parasite with a complex life cycle.

Many diseases are caused by parasites with complex life cycles that involve several hosts. If parasites cope better with only one of the different types of immune systems of their host species, we might expect a trade-off in parasite performance in the different hosts, that likely influences the evolution of virulence. We tested this hypothesis in a naturally co-evolving host-parasite system consisting of the tapeworm Schistocephalus solidus and its intermediate hosts, a copepod, Macrocyclops albidus, and the three-spined stickleback Gasterosteus aculeatus. We did not find a trade-off between infection success in the two hosts. Rather, tapeworms seem to trade-off adaptation towards different parts of their hosts' immune systems. Worm sibships that performed better in the invertebrate host also seem to be able to evade detection by the fish innate defence systems, i.e. induce lower levels of activation of innate immune components. These worm variants were less harmful for the fish host likely due to reduced costs of an activated innate immune system. These findings substantiate the impact of both hosts' immune systems on parasite performance and virulence.

Adaptation, Physiological↗

Outcrossing increases infection success and competitive ability: experimental evidence from a hermaphrodite parasite.

The maintenance of two genetically distinct reproductive modes such as outcrossing and selfing within a population of animals or plants is still a matter of considerable debate. Hermaphroditic parasites often reproduce either alone by selfing or in pairs by outcrossing. They can be used as a model to study potential benefits of outcrossing. Any advantage from outcrossing may be important, especially in host-parasite coevolution, but has not, to our knowledge, been studied yet in any parasite species. We studied the potential effect of outcrossing in a tapeworm, Schistocephalus solidus, on both infection success and growth in its first intermediate host, the copepod Macrocyclops albidus. Tapeworms that had been obtained from natural populations of three-spined sticklebacks (Gasterosteus aculeatus) were allowed to reproduce either alone or in pairs, in an in vitro system that replaced the final host's gut. This resulted in either selfed or outcrossed offspring, respectively. In one part of the experiment, copepods were exposed to either selfed or outcrossed parasites, in a second part to both types simultaneously, in order to study the effect of competition between them. To discriminate parasites of either origin within the same host, a novel method for fluorescent vital labeling was used. We show here for the first time that outcrossed parasites had a higher infection success and faster development in the host. This advantage of outcrossing became apparent only in the competitive situation, in which superior abilities of parasites to extract limiting resources from the host become crucial.

Animals↗

Taenia solium taeniasis and cysticercosis in three communities in north Vietnam.

OBJECTIVES: (1) To investigate the response to a serum antigen-detecting ELISA for cysticercosis and a stool coproantigen test for taeniasis in two rural communities (mountainous and coastal areas) and one group of (peri-)urban factory workers; and (2) to examine clinical features of human cysticercosis in northern Vietnam. METHODS: Villagers and factory workers and their families were informed and invited to participate in the study. Blood and faecal samples were collected from the participants and a simple questionnaire on taeniasis/cysticercosis completed. Serum was examined for the presence of circulating cysticercus antigen by a monoclonal-based sandwich ELISA. Ag-ELISA positive persons underwent a clinical examination and a computed tomography (CT) scan. Stool samples were examined microscopically for the presence of Taenia eggs and for copro-antigens. Tapeworms were identified following therapeutic expulsion using morphology and PCR-RFLP. RESULTS: Circulating cysticercus antigens, suggesting active infection, were detected in 5.3% (16/303), 0.6% (1/175) and 0.0% (0/229) of the sampled individuals from the mountainous, coastal and urban regions, respectively. Clinical examination and CT scan of the cysticercus antigen positive persons showed that active cysticercosis did not cause severe disease in most cases. Taenia copro-antigens were found in 0.3% (1/297), 1.8% (3/166) and 0.0% (0/228) of the stool samples from the mountainous, coastal and urban communities, respectively. Three tapeworms were expelled after treatment: two Taenia solium and one Taenia saginata. CONCLUSION: This survey points to a focal distribution of taeniasis/cysticercosis and suggests that human cysticercosis is rather acquired due to close contact with a T. solium carrier and self-infection, than through infection from the environment.

Adolescent↗

Sero-prevalence of Taenia solium cysticercosis and Taenia solium taeniasis in California, USA.

OBJECTIVES: Taenia solium Cysticercosis is a leading cause of epilepsy and neurological disability in the developing world. It is caused by ingestion of the eggs of the tapeworm, T. solium Taeniasis. The prevalence of either T. solium Cysticercosis or T. solium Taeniasis in the United States in populations at risk is poorly understood. The primary objectives of this study are to perform the first study of the sero-prevalence of T. solium Cysticercosis and T. solium Taeniasis in an at-risk community in the USA, specifically rural Southern California; identify T. solium Taeniasis positive individuals, and treat positive individuals for the tapeworm T. solium Taeniasis. METHODS: Community based sero-prevalence study of antibodies to T. solium Cysticercosis and T. solium Taeniasis in 449 subjects living in a federally funded, predominantly Hispanic residential community; and in two migrant farm worker camps in rural Ventura County, California, USA. For this study, fingerstick blood samples were obtained. Serum immunoblots for both T. solium Cysticercosis and T. solium Taeniasis were performed. RESULTS: The sero-prevalence of T. solium Cysticercosis was 1.8% and the sero-prevalence of T. solium Taeniasis by serum immunoblot was 1.1%. Taenia solium Cysticercosis and T. solium Taeniasis antibodies were not detected in children. The sero-prevalence of T. solium Taeniasis was highest in the migrant farm worker community. Handwashing frequency was correlated with T. solium Taeniasis sero-positivity. CONCLUSION: The sero-prevalence of T. solium Cysticercosis and T. solium Taeniasis in this population, as detected by serum immunoblot, approximates the prevalence in some endemic areas of Latin America. Importantly, most patients likely had prior exposure, not active infection. This study establishes for the first time, the relative sero-prevalence of T. solium Cysticercosis and T. solium Taeniasis in at-risk populations in the United States.

Adolescent↗

Isolation and characterization of species-specific DNA probes from Taenia solium and Taenia saginata and their use in an egg detection assay.

Cysticercosis results from ingestion of the eggs of the tapeworm Taenia solium. Reduction of the incidence of human and swine cysticercosis requires identification and treatment of individuals who carry the adult tapeworm. T. solium and Taenia saginata eggs cannot be differentiated on the basis of morphology; thus, in order to improve existing methods for the diagnosis of taeniasis, we have developed highly sensitive, species-specific DNA probes which differentiate T. solium and T. saginata. Recombinant clones containing repetitive DNA sequences which hybridize specifically with genomic DNAs from either species were isolated and characterized. T. solium-specific DNA sequences contained complete and truncated forms of a tandemly repeated 158-bp DNA sequence. An unrelated T. saginata DNA sequence was also characterized and shown to encode a portion of the mitochondrial cytochrome c oxidase I gene. T. solium- and T. saginata-specific DNA probes did not hybridize in dot blot assays either with genomic DNA from the platyhelminths Taenia hydatigena, Taenia pisiformis, Taenia taeniaeformis, Echinococcus granulosus, and Schistosoma mansoni or with genomic DNA from other eukaryotes, including Saccharomyces cerevisiae, Candida albicans, Cryptosporidium parvum, Entamoeba histolytica, Trypanosoma gambiense, Trypanosoma brucei, and Giardia lamblia, Caenorhabditis elegans, and human DNA. By using these T. solium and T. saginata DNA probes, a rapid, highly sensitive and specific dot blot assay for the detection of T. solium eggs was developed.

Animals↗

Prevalence and diagnosis of parasites of the stomach and small intestine in horses in south-west England.

Parasites were extracted from the stomach and small intestine of 118 horses at slaughter. The most abundant species was the tapeworm Anoplocephala perfoliata. Maximum likelihood analysis was used to investigate the relationship between the number of worms and their total weight, and the ability of an antibody-based elisa to diagnose the level of infection. The total weight of tapeworms increased towards a maximum as the number of worms increased, suggesting a population density-dependent constraint on the weight. The number of A perfoliata present could be predicted approximately from the results of the elisa. Although wide variation in elisa optical densities confound interpretation in individual animals, tests on groups of animals could provide a useful reflection of overall levels of infection.

Abattoirs↗

Fibrosarcomas in two rats arising from hepatic cysts of Cysticercus fasciolaris.

Two of five male Sprague-Dawley rats with hepatic tapeworm cysts developed large multinodular fibrosarcomas. Fibrosarcomas envelope tapeworm cysts, invaded the serosa of multiple organs, and extended through the diaphragm into the pleural cavity. Light microscopy, immunohistochemistry, and electron microscopy supported the diagnosis of fibrosarcoma. The parasites were identified as Cysticercus fasciolaris, the larval stage of Taenia taeniaeformis. The development of sarcomas in rats induced by Taenia sp. is thought to be attributable to the chronic inflammatory reaction of the capsule. There are parallels between these and other tumors occurring in mice and cats with suggested chronic inflammatory etiologies.

Animals↗

Fine structure of the male reproductive ducts, vagina and seminal receptacle of Cyathocephalus truncatus (Cestoda: Spathebothriidea).

Fine structure of the vas efferens, vas deferens, ejaculatory duct with accessory glands and vagina with seminal receptacle is described in the spathebothriidean tapeworm, Cyathocephalus truncatus (Pallas, 1781) Kessler, 1868. The numerous well-developed prostate glands are characterised by having secretory granules with an electron-dense core surrounded by a matrix of lower electron density. Coalescence of the outer part of the granules with each other takes place in the terminal end of the secretory ducts. The position of prostate glands around the proximal part of the cirrus pouch and terminating in the ejaculatory duct is a characteristic feature of the Spathebothriidea. Up to 20 closely arranged muscle layers make up the muscular cirrus pouch wall with 4 well-developed muscular layers in the ejaculatory duct and cirrus. Both the cirrus and the vagina are covered with the same uniform cone-shaped microtriches. The vagina has an extensive seminal receptacle. All of these structures are well-adapted to insure successful sperm transfer involving ejaculation and storage, probably for both self- and cross-insemination. Cyathocephalus truncatus has a cirrus similar to that of the monozoic, progenetic caryophyllidean, Archigetes sieboldi and well-developed prostate glands like those of the polyzoic pseudophyllidean, Diphyllobothrium latum. The ultrastructural aspects of the male and female reproductive system of C. truncatus are compared with those of other tapeworms.

Animals↗

Fine structure of the female reproductive ducts of Cyathocephalus truncatus (Cestoda: Spathebothriidea), from salmonid fish.

The fine structure of the ovary, ovicapt, oviduct, fertilisation canal, vitelline ducts, vitelline reservoir, ovovitelline duct, ootype and Mehlis' gland, and proximal, middle and distal parts of the uterus of the spathebothriidean cestode, Cyathocephalus truncatus (Pallas, 1781), from salmoniform fish, has been studied for the first time by transmission electron microscopy (TEM). Emphasis was given to characteristics which might shed light on the unclarified phylogenetic position of spathebothriideans, belonging among the most basal tapeworms (Eucestoda). New for cestodes is the finding of a multinucleate cell that plugs the ovicapt lumen. The morphology of the proximal part of the oviduct resembles that of the pseudophyllidean tapeworm Diphyllobothrium latum. After fertilisation in the fertilisation canal, vitellocytes of C. truncatus become associated with fertilized oocytes in the ovovitelline duct. Only one type of Mehlis' gland secretory cell is present. The eggs with electron-dense eggshells containing large pores first appear in the proximal part of the uterus. The middle portion of the uterus has well-developed uterine glands. The distal portion of the uterus has apical microtriches. Ultrastructural data on the female genital system of C. truncatus are compared and discussed with those for other cestodes. However, on the basis of available ultrastructural data it is not possible to conclude whether the Spathebothriidea are phylogenetically closer to the Caryophyllidea or to the Pseudophyllidea.

Animals↗

Meriones meridianus and Lagurus lagurus as alternative definitive hosts of Echinococcus multilocularis and E. granulosus.

The utilization of Meriones meridianus and Lagurus lagurus as alternative definitive hosts for Echinococcus multilocularis and E. granulosus was investingated. Tapeworm stage development of E. multilocularis was observed and their recovery rate was determined in the small intestine of M. meridianus and L. lagurus. These were compared with those in golden hamsters, which are known as alternative definitive hosts. The animals were treated with PTBA (prednisolone tertiary butylacetate) and PA (prednisolone acetate), after which M. meridianus showed the highest recovery rate, whereas L. lagurus had few or no worms. The recovery rate of worms from golden hamsters was between those of M. meridianus and L. lagurus. On day 20 post-infection, developing tapeworms with mature segments were collected from M. meridianus treated with PA. The worms were mostly from the proximal and medial small intestine. The three species of animals infected orally with E. granulosus were divided into two groups, PTBA-treated and non-treated control groups. PTBA promoted/enhanced the recovery rate of the worms until 5 days, but none or only a few worms were found in PTBA treated animals thereafter. The highest recovery rate was obtained from M. meridianus treated with PTBA on day 5 post-infection. Some worm developments were observed on days 5 and 10 post-infection. These results demonstrate that M. meridianus could be useful as an alternative definitive host of Echinococcus.

Animals↗

The finding of eggs of Diphyllobothrium in human coprolites (4,100-1,950 B.C.) from northern Chile.

Twenty six coprolites from an archaeological site in the province of Iquique, northern Chile, were examined for parasites. Coprolites were found in two excavation units, I and II (Tiliviche site), dated respectively at 5,900 B.C. to 4,110 B.C. and 4,110 B.C. to 1,950 B.C., and identified as of human origin. Only at the unit II coprolites containing helminth eggs identified as Diphyllobothrium pacificum were found. The presence of this tapeworm, a parasite of the American Sea Lion, in human coprolites, points to a diet which included marine fishes and provides information on the antiquity of infection by Diphyllobothrium pacificum. It is interesting to note that Baer (1969) suggests the presence of this tapeworm in pre-Columbian populations when diagnosing the first human cases in today's population in Peru.

Chile↗

Inhibitory role of antibodies in the development of Taenia solium and Taenia crassiceps toward reproductive and pathogenic stages.

Untreated Taenia solium cysticerci obtained from different naturally infected pigs vary notably in their capacity to develop into intestinal tapeworms in prednisolone-treated hamsters, whereas cells derived from Taenia crassiceps cysticerci after 2 mo of infection almost always develop to cysticerci in the peritoneal cavity of susceptible BALB/cAnN mice. Preincubation of whole cysticerci or parasite cells with mice immunoglobulins raised against an 18-mer peptide epitope (GK-1) common to both parasites significantly interferes with both transformations. These crippling effects of antiparasite antibodies suggest new forms of immunological interference with parasite biology other than simple killing. Antibodies that cripple biological functions of the parasite, e.g., their development to reproductive or pathogenic stages, make them important protagonists in taeniasis/cysticercosis disease as classic parasitocidal antibodies. Different serum levels of crippling antibodies in the infected pigs could be responsible for the varied ability of cysticerci to convert to tapeworms. Antigens capable of inducing crippling antibodies, e.g., GK-1, could be useful as a therapeutic vaccine for pigs in order to reduce parasite transmission.

Animals↗

Four new genera and five new species of lecanicephalideans (Cestoda: Lecanicephalidea) from elasmobranchs in the Gulf of California, Mexico.

A total of 53 spiral intestines from 3 species of rays collected in the Gulf of California, Baja, Mexico, was examined for cestodes of the order Lecanicephalidea. Four new genera and 5 new species were discovered as a result of this study. These are Aberrapex senticosus n. gen., n. sp., from Myliobatis californica, Paraberrapex manifestus n. gen., n. sp., from Squatina californica and Healyum harenamica n. gen., n. sp., Healyum pulvis n. sp. and Quadcuspibothrium francisi n. gen., n. sp., from Mobula japanica. Aberrapex n. gen. and Paraberrapex n. gen. can be distinguished from all other lecanicephalidean genera based on the lack of an apical structure (pars apicalis) on their scolex. Aberrapex n. gen. can be distinguished from Paraberrapex n. gen. based on the presence of an external seminal vesicle, a vagina positioned lateral rather than medial in the proglottid, and an ovary that is tetralobed rather than bilobed in cross section. Healyum n. gen. and Quadcuspibothrium n. gen. are unique among lecanicephalidean genera, including Aberrapex n. gen. and Paraberrapex n. gen., in their possession of a trilobed ovary in cross section. Quadcuspibothrium n. gen. can be distinguished from Healyum n. gen. based on its unique shape of the acetabula, which are diamond-shaped. The 2 species of Healyum n. gen. can be distinguished from one another based on the dimensions and the shape of the scolex, the diameter of the suckerlike acetabula, as well as the shape of the spiniform microtriches on the acetabular rims. Discobothrium arrhynchum is transferred to the genus Aberrapex n. gen. and the original description of this species is emended to include details of the vas deferens and the uterine duct and uterus. The microtrich patterns of the 5 new species and Aberrapex arrhynchum n. comb. are described. These are the first records of tapeworms of the Lecanicephalidea from the Gulf of California. Squatina californica and Mobula japanica represent new host records for lecanicephalidean tapeworms. The ordinal diagnosis of the Lecanicephalidea by Euzet (1994) is emended to include these 4 new genera.

Animals↗

Two new species of Yorkeria (Tetraphyllidea: Onchobothriidae) from Chiloscyllium punctatum (Elasmobranchii: Hemiscylliidae) in Thailand.

Two new species of the tapeworm genus Yorkeria are described from the spiral intestine of a specimen of the Brownbanded bambooshark, Chiloscyllium punctatum, collected from a fish market in Bangsarai, Thailand in 1996. The larger of the 2 new tapeworm species, Y. hilli, possesses fewer proglottids, fewer testes, and is smaller than most of its congeners. The smaller of the 2 new species, Y. kelleyae, conspicuously differs from all of its congeners in its possession of medial hooks that are only slightly larger than the lateral hooks (rather than conspicuously larger). Scanning electron microscopy shows both species to possess elongate filitriches on their distal prehook locular surfaces and elongate filitrichs and spinitrichs on their proximal bothridial, distal posthook locular surfaces, pedicels, and cephalic peduncles. In both species, the spinitrichs on the proximal bothridial surfaces, pedicels, and peduncles are very large and readily visible with light microscopy. Whereas the spinitrichs on these 4 surfaces are bluntly rounded in Y. hilli, they are pointed in Y. kelleyae. Examination of specimens identified as Y. parva, collected by several previous workers from a diversity of hosts and localities, calls into question the conspecificity of at least some of this material. The unusual scolex form suggests that the configuration of the cerebral ganglionic mass in species of Yorkeria may differ from that seen in most other tetraphyllidean taxa.

Animals↗

Host specificity and population structure of two exotic helminths, Camallanus cotti (Nematoda) and Bothriocephalus acheilognathi (Cestoda), parasitizing exotic fishes in Waianu Stream, O'ahu, Hawai'i.

Introduction of exotic fishes into Hawai'ian streams has resulted in the simultaneous introduction of exotic parasites. Camallanus corti (Nematoda) and Bothricephalus acheilognathi (Cestoda) are the most prevalent and abundant fish helminths in Hawai'ian streams. The population structure and host specificity of C. cotti and B. acheilognathi in exotic poeciliids were examined during May and June 1995 in Waianu Stream, O'ahu, Hawai'i. Prevalence and mean abundance of C. cotti were significantly different among Poecilia reticulata (65.2%, 1.05), Poecilia mexicana (49.0%, 0.87), and Xiphophorus helleri (32.3%, 0.44). Prevalence of B. acheilognathi was significantly higher in P. mexicana (6.1%) than in P. reticulata (2.1%) and X. helleri (1.6%). However, tapeworm differences in mean abundance were not significant among P. mexicana (0.08), P. reticulata (0.04), or X. helleri (0.03). Nematode and tapeworm prevalence and mean abundance were not significantly different with regard to fish sex. Camallanus cotti prevalence and mean abundance increased as P. mexicana body size increased (r2 = 0.84 and r2 = 0.72, respectively), whereas B. acheilognathi displayed no significant trend with respect to poeciliid body size.

Analysis of Variance↗