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PubMed2001

Out of Africa: origins of the Taenia tapeworms in humans.

Phylogenetic and divergence date analyses indicate that the occurrence of Taenia tapeworms in humans pre-dates the development of agriculture, animal husbandry and domestication of cattle (Bos spp.) or swine (Sus scrofa). Taeniid tapeworms in Africa twice independently colonized hominids and the genus Homo prior to the origin of modern humans. Dietary and behavioural shifts, from herbivory to scavenging and carnivory, as early Homo entered the carnivore guild in the Pliocene/Pleistocene, were drivers for host switching by tapeworms to hominids from carnivores including hyaenids and felids. Parasitological data provide a unique means of elucidating the historical ecology, foraging behaviour and food habits of hominids during the diversification of Homo spp.

Africa↗
PubMed1998

Tapeworm infection is a significant risk factor for spasmodic colic and ileal impaction colic in the horse.

The association between the equine intestinal tapeworm Anoplocephala perfoliata and specific types of intestinal disease was investigated by matched case-control study using coprological and serological diagnosis. We have previously shown that the host IgG(T) response to 12/13 kDa antigens of A. perfoliata correlates well with infection intensity, therefore this antibody response was used to investigate the risk of colic at different levels of parasite infection intensity. One hundred and three spasmodic colic cases with an equal number of controls matched for age, breed and gender, and 20 ileal impaction cases each with 2 similarly matched controls were obtained. Cases of spasmodic colic were much more likely (odds ratio = 8.0) to be associated with A. perfoliata infection detected coprologically than controls. Serological diagnosis revealed an increasing risk of spasmodic colic with increasing infection intensity. Calculation of an aetiological fraction suggests that 22% of spasmodic colic cases in this study were tapeworm associated. No significant association was found between colic and strongyle egg count. Conditional logistic regression analysis demonstrated that the relationship between colic and A. perfoliata infection intensity was not confounded by strongyle egg count and there was a linear relationship between infection intensity and the log-odds of spasmodic colic. For cases of ileal impaction, a strong association was found between colic and A. perfoliata as diagnosed by coprological means (odds ratio of 34.0). Serological diagnosis also revealed a strong association that increased with higher levels of infection intensity (odds ratio = 26.0). The aetiological fraction for the ileal impaction data suggests that 81% of the ileal impaction cases in this study were tapeworm associated. This study concludes that A. perfoliata is a significant risk factor for spasmodic colic and ileal impaction colic in the horse; and that the risk of spasmodic colic increases with infection intensity.

Animals↗
PubMed2004

Field trial of the efficacy of a combination of ivermectin and praziquantel in horses infected with roundworms and tapeworms.

Two hundred and thirty-three horses were screened for the presence of roundworms by faecal egg counts (FECs) and for tapeworms by an ELISA specific for antibodies to the immunodominant 12 kDa and 13 kDa tapeworms antigen. The 62 horses were found to be infected with both parasites were treated with a combination of 0.2 mg/kg ivermectin and 1.5 mg/kg praziquantel. The treatment suppressed the median FEC of the horses to zero for 10 weeks and significantly reduced their anti-12/13 kDa antibody levels. The estimated risk of tapeworm-associated colic in these horses was halved by 12 weeks after the treatment.

Animals↗
PubMed2001

Modulation of caudal intestinal permeability in the rat during infection by the tapeworm Hymenolepis diminuta.

Bidirectional movement of solutes between the intestinal lumen and systemic circulation is restricted by tissue barriers that may be altered under conditions such as intestinal infection. In a study using an in vitro everted sac preparation to assess small intestinal permeability in a lumen-to-serosa direction, 51Cr-EDTA movement was compared regionally in the jejunum and ileum of rats infected and uninfected by tapeworms. Whereas jejunal segments showed no significant differences in permeability to 51Cr-EDTA at 6, 15, or 32 days postinfection (dpi), ileal segments displayed an increased permeability on 15 and 32 dpi, but not 6 dpi. The alterations in permeability were not reversed 1 wk after removal of the tapeworm from the intestine. In conclusion, the strictly lumen-dwelling tapeworm infection allows increased movement of molecules from the lumen into ileal, but not jejunal, tissues by 15 dpi.

Animals↗
PubMed2005

Aspects of the ecology of the Asian tapeworm, Bothriocephalus acheilognathi Yamaguti, 1934 in yellowfish in the Vaal Dam, South Africa.

Seasonal surveys were conducted at the Vaal Dam between April 2000 and January 2001. Twenty smallmouth yellowfish (Labeobarbus aeneus) and 20 largemouth yellowfish (Labeobarbus kimberleyensis) were collected with the aid of gill nets. Surface water quality variables were included. The cestodes were identified as either Bothriocephalus acheilognathi Yamaguti, 1934 or "other cestode spp.". The majority (99.8%) of the cestodes found in both yellowfish species were identified as B. acheilognathi (Asian tapeworm). The prevalence, mean intensity and abundance of B. acheilognathi in both yellowfish species were calculated. Ecological parameters including species specificity, seasonality, gender specificity and relationships between fish size and the Asian tapeworm prevalence were also included. In this study, B. acheilognathi preferred L. kimberleyensis over L. aeneus although a low intensity was observed in smallmouth yellowfish. Furthermore, the infection (in terms of prevalence, abundance and mean intensity) in largemouth yellowfish was markedly higher. Seasonal patterns observed in the Asian tapeworm's infection of smallmouth yellowfish are attributed to breeding and subsequent feeding patterns of this fish species with relatively high infections recorded in winter and spring. For L. kimberleyensis no explanation can be given regarding the seasonal patterns observed for the mean intensity and abundance of B. acheilognathi. The maximum and minimum mean intensity and abundance values in largemouth yellowfish were recorded in autumn and spring, respectively. In addition, the prevalence of B. acheilognathi was consistently high in all four seasons.

Animals↗
PubMed1992

Cysticercosis surveillance: locally acquired and travel-related infections and detection of intestinal tapeworm carriers in Los Angeles County.

A surveillance system for cysticercosis was initiated in January 1988 in Los Angeles County to measure the incidence of the disease, to more accurately assess the level of locally acquired and travel-related infection, and to evaluate household contacts for intestinal tapeworm infection. In three years of surveillance (1988-1990), 138 incident cases were reported for an average crude annual incidence rate of 0.6 per 100,000 population. The highest rates were among Hispanics (1.6/100,000), most of whom were Mexican immigrants. Eight (5.8%) cases were fatal. Nine (6.5%) probable travel-associated cases occurred among persons born in the United States who had traveled to Mexico. Ten (7.2%) autochthonous cases of cysticercosis were documented. Taenia eggs were recovered more commonly in specimens from contacts with cysticercosis cases (1.1%) than in specimens from noncontact patients (0.2%). At least one Taenia tapeworm carrier was found among contacts of five (6.9%) of 72 cysticercosis patients. Carriers were more likely to be found among contacts of patients born in the United States (22.2%) than among those of foreign-born (4.8%) patients (odds ratio = 5.4) Cysticercosis causes appreciable morbidity and mortality in Los Angeles County, principally among Hispanic immigrants. However, these results indicate that both travel-acquired and locally acquired cysticercosis may be more common than previously recognized. Public health followup of cysticercosis cases, including screening of household contacts, can identify tapeworm carriers, who can be treated and removed as potential sources of further infection.

Adolescent↗
PubMed1976

Comparative effects of uredofos, niclosamide, and bunamidine hydrochloride against tapeworm infections in dogs.

A single dose of a new broad-spectrum anthelmintic, uredofos, was more effective than single doses of either bunamidine hydrochloride (HCI) or niclosamide in removing natural infections of Dipylidium coninum from pound dogs, as determined by necropsy examination for scolices. The efficacy of uredofos was equal to that of bunamidine HCI and exceeded that of niclosamide in removing Taenia spp from his host. All of 12 dogs harboring D caninum and all of 5 dogs harboring Taenia spp were completely cleared of tapeworm infection following treatment with uredofos at 50 mg/kg of body weight. Bunamidine HCl cleared 9 of 11 dogs (82%) of D caninum and 5 of 5 dogs of Taenia spp. Niclosamide had the least anticestodal activity of the 3 drugs; 2 or more scolices of D caninum were found at necropsy in each of 12 dogs treated with this drug. Four of 5 dogs were cleared of Taenia spp following niclosamide therapy. Untreated control dogs did not shed tapeworms of either species during a 3-day period of posttreatment fecal collections, but did have tapeworms at the time of necropsy.

Amidines↗
PubMed1992

[Comparison of thymidylate synthase properties isolated from the rat tapeworm, hymenolepis diminuta, with properties of enzyme isolated from the host in regenerating rat liver].

Thymidylate synthases (TS) from the tapeworm, Hymenolepis diminuta, and regenerating rat liver have been purified by means of affinity chromatography on immobilized 10-formyl-5,8-dideazafolate and concentrated on immobilized p-aminophenyl-5-fluoro-2'-deoxyuridine monophosphate. Molecular weights of native TS from the tapeworm and regenerating rat liver were 62 kD and 81.5 kD, respectively, and molecular weights of the monomers were 34.4 kD and 34.9 kD, respectively, pointing to dimeric structures of both enzymes. The dependence of TS activity on temperature (Arrhenius plot) was biphasic for the parasite enzyme, with lower activation energy above 32 degrees C, and monophasic for the host enzyme. 2'-deoxyuridine-5'-monophosphate (dUMP) analogues, 5-fluoro-2'-deoxyuridine-5'-monophosphate (5-FdUMP), 2-tio-5-FdUMP,N4-hydroxy-2'-deoxycytidine-5'-monophosphate (N4-hydroxy-dCMP) and N4-hydroxy-5-FdCMP, were competitive with respect to dUMP, slow-binding inhibitors of TS from both sources, with K1 values in 10(-6)-10(-9) M range. 5-FdUMP was distinctly stronger inhibitor of the host than the tapeworm TS, whereas N4-hydroksy-5-FdCMP inhibited stronger the parasite enzyme. Interaction of 5,10-methylenetetrahydrofolate (CH2H4PteGlu) analogue, 10-propargyl-5,8-dideazafolate (pddPteGlu), and its di- and triglutamates with both enzymes were studied. Inhibition of the parasite and host enzymes by pddPteGlu was of mixed-type with respect to CH2H4PteGlu, with K1 values in 10(-8) M range. Introduction of additional glutamate residues changed inhibition type to noncompetitive with respect to Ch2H4PteGlu and lowered K1 values (pddPteGlu3 < pddPteGlu2 < pddPteGlu1).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

[The evolution of forms of hermaphroditism in Cyclophyllidea (Cestoda). 1. Morpho-functional causes of the formation of tapeworms with the protandrous type of genital apparatus development].

Morpho-fuctional causes of the formation of protandrous Cyclophyllidea (tapeworms) have been studied. Two forms of protandry are described. The protandry type I is typical for polymeric (polysegmental) Hymenolepididae. It appears independently in different taxa of this family (Aploparaksis, Echinatrium, Wardium, Diorchis and others) while the narrow-strobila forms with a low prolificacy of proglottids are formed. The development of this living form of hymenolepidids is ecologically caused by the high density of their aggregation in intestines of hosts. The primordium results in the development of genitals in the juvenile strobila proglottids with the limited internal space. Due to this process, parallel morphogenesis of male and female gonads is proved to be impossible. A selection leading to the overtaking development of testicles and copulative apparatus regarding morphogenesis of ovary and vitellarium is based an earlier maturation of testicles and group copulation of proglottids with and underdeveloped ovary that is typical in original euandrogyne forms. The group insemination of proglottids from a polysegmented strobila reduces the number of copulation and improves an efficiency of cross-copulation of tapeworms and. As a result, morpho-functional zones of male proglottids characterized by an immature ovary and those of fertile female segments losing their testicles are differentiated in the strobila. The protandry type II is typical of mesomeric tapeworms (Dilepididae, Schistotaeniidae, Anoplocephalidae). It is also resulted from a limited space of proglottids for developing the hermaphroditic genital apparatus. This is caused by the shift of genital morphogenesis process into juvenile proglottids and also by the enlargement of gonad sizes as the result of a selection for a higher prolificacy of proglottids. The dissociation of the development of male and female gonads takes place because of the retardation of ovary morphogenesis.

Animals↗
PubMed1991

Laboratory rodent models for the tapeworm-stage of Taenia saginata and other related taeniid species.

Attempts were carried out to establish alternative definitive host systems for Taenia saginata, T. crassiceps, T. hydatigena, Echinococcus multilocularis and E. granulosus, in rodents. Following oral inoculation of cysticerci or protoscoleces, the tapeworm-stage development and sexual maturation of the 5 taeniid species in the intestine of a golden hamster (GH) and Mongolian gerbil (MG), both treated with prednisolone, were examined. Sexually mature T. saginata tapeworms were recovered from MG pretreated with prednisolone. The life cycles of E. multilocularis can be completed in MG and T. crassiceps in both MG and GH. T. hydatigena and E. granulosus developed to a certain extent at the tapeworm stage in MG pretreated with prednisolone. Potential use of rodents as an alternative definitive host for taeniid species is discussed.

Animals↗
PubMed1988

Interaction of bass tapeworm, Proteocephalus ambloplitis, and Neoechinorhynchus sp. (Acanthocephala) in largemouth bass, Micropterus salmoides.

The number of plerocercoids of the bass tapeworm, Proteocephalus ambloplitis, in wild largemouth bass was negatively correlated (r = -0.94) with the number of Neoechinorhynchus sp. Competitive inhibition between the 2 parasites appeared to exist. Similarly, the numbers of Neoechinorhynchus sp. in wild bass decreased when adult bass tapeworms were present in the intestine. Proteocephalus ambloplitis plerocercoids used to challenge bass vaccinated with either P. ambloplitis adult or Neoechinorhynchus sp. antigens were smaller (P less than 0.05) when recovered than those used to challenge control bass. Based on preliminary results, both antigens might have enabled the bass to limit growth and/or development of the invading bass tapeworm, plerocercoids. Cross-protective immunity may be the reason for this occurrence, in which case, it could offer an explanation for competitive inhibition existing between P. ambloplitis and Neoechinorhynchus sp.

Acanthocephala↗
PubMed1984

Fish tapeworm infections (diphyllobothriasis) in Canada, particularly British Columbia.

Although the risk of diphyllobothriasis is generally low in Canada, fish tapeworm infections seem to have become more frequent in recent years. This increase is probably a consequence of the growing popularity of raw or inadequately cooked ethnic fish dishes or of a preference for lightly cooked fish, especially salmon. Only freshwater fish become infected with the larvae, but not everyone may realize that salmon can acquire the parasites before they leave their native lakes and rivers for the sea. If fish known to be sources of the tapeworms are to be eaten raw they should first be well frozen or salted to kill the larvae. Physicians should regard fish tapeworm infection as a notifiable disease. In Canada niclosamide, the drug of choice, is available from the manufacturer on a patient-by-patient basis.

Animals↗
PubMed1983

Parasites in Kentucky Thoroughbreds at necropsy: emphasis on stomach worms and tapeworms.

A total of 363 Thoroughbreds (62 males, 292 females, and 9 geldings), 1 to 26 years of age, were examined at necropsy for internal parasites for about a 12-month period from February 1981 through February 1982. Emphasis was on examining the stomach for nematodes and the small intestine and cecum for tapeworms. Parasites recovered from the stomach and infection rates were: Habronema spp--immature (24%), H muscae--adult (38%), Draschia megastoma--immature (13%), D megastoma--adult (62%), and Trichostrongylus axei--adult (4%); lesions caused by D megastoma were found upon gross observation in 58% of the stomachs. The tapeworm, Anoplocephala perfoliata, was recovered from 54% of the horses; A magna was not found. There was no obvious difference in infection rates of the stomach worms and tapeworms according to age or sex of the horses. Seasonal differences were apparent only for immature Habronema spp and immature D megastoma for which infection rates began increasing in June, peaking in October, and declining thereafter. Presence of 4 additional species of parasites was recorded, but only a cursory examination was made for them. These were the large strongyles, Strongylus vulgaris, S edentatus, and S equinus, from the cecum and a filariid, Setaria spp (probably S equina), from the abdominal cavity, for which recovery rates from the horses were 8%, 8%, 1%, and 7%, respectively.

Animals↗
PubMed1995

Infection of Tribolium beetles with a tapeworm: variation in susceptibility within and between beetle species and among genetic strains.

Host susceptibility and resistance to parasites are often hypothesized to be genetically variable traits. We tested 2 species of Tribolium flour beetles for among-strain variation in susceptibility to the rat tapeworm Hymenolepis diminuta. Twelve genetic strains of Tribolium confusum and 11 strains of Tribolium castaneum were examined. We found T. castaneum was more susceptible to the tapeworm than T. confusum. There was significant among-strain and between-sex variation for both beetle species in infection intensity and prevalence. Among-vial variation was marginally significant. These results add to evidence that host susceptibility to a parasite is a genetically variable trait. We view these results as important findings for understanding natural selection on host-parasite interactions. Traits that are genetically variable can respond to natural selection. Thus, if a beetle's susceptibility to the tapeworm is correlated with fitness and heritable, susceptibility can evolve. Susceptibility is likely to be pleiotropic and have important consequences on issues ranging from parasite transmission to host species interactions and community structure.

Analysis of Variance↗
PubMed1976

Public health significance of zoonotic tapeworms in Korea.

Through an epidemiological review on the zoonotic tapeworms in Korea, the frequency and severity of the zoonoses have been recognized. Taeniasis and human cysticercosis are of importance to the public health in Korea. The frequency of taeniasis is 0.3% to 12.7% discovered by stool examination and 4.5% to 38.0% discovered by questionaire survey. Taeniasis occurs more frequently in males than in females and, especially, in both sexes in the age-group of 20 to 49. T. saginata is more common that T. solium. No case of human cysticercosis caused by T.saginata has been reported in Korea. To the contrary, human cysticercosis caused by T. solium has been reported frequently during the 1960's. The severity of human cysticercosis is a significant problem of public health in Korea. Old data on bovine cysticercosis in the 1920's and 1930's are not useful for present control measures. Systematic surveys on bovine and swine cysticercosis as well as taeniasis and human cysticercosis are needed in Korea. Cases of sparganosis have been reported frequently during the past 15 years. Most of the 34 cases of sparganosis reported involved the eating of raw snakes and frogs. Most of the cases occurred in older males. Sparganosis in snakes, frogs, chickens, and swine has been reported in Korea. Human infection of Hymenolepis nana ranged from 0.2% to 1.4% discovered by stool examination. A few cases of adult worm collections of Diphyllobothrium latum and Hymenolepis diminuta have been reported in Korea. Two cases of human hydatid disease have been reported in Korea. No study on the disease in domestic animals is available. No case of human infection with dog tapeworm has been reported, even though it is highly prevalent in the indigenous dogs in Korea. I recommend that further study on the zoonotic tapeworms be conducted epidemiologically in Korea to get basic data for the public health programming.

Adolescent↗
PubMed1986

Trace element content in two species of whale tapeworms, Diphyllobothrium macroovatum and Diplogonoporus balaenopterae.

Trace elements in two species of whale tapeworms, Diphyllobothrium macroovatum and Diplogonoporus balaenopterae, were analysed by atomic absorption spectroscopy. Six elements (Fe, Cu, Zn, Mn, Cd, Ca) were assayed from different regions of two tapeworms: scolex, neck, immature, mature and gravid proglottids. Whole strobilae at different stages of maturity were also examined. The relationship between the trace element content and the physiological significance is discussed.

Animals↗
PubMed1991

Development and dynamics of regional specialization within the syncytial epidermis of the rat tapeworm, Hymenolepis diminuta.

The epidermis of the tapeworm Hymenolepis diminuta is a highly organized syncytium, composed of an outer layer of continuous cytoplasm, or ectocytoplasm, and an inner layer of nucleated cell bodies, or perikarya. The perikarya are in direct cytoplasmic continuity with the ectocytoplasm via narrow plasmalemma-bound bridges called internuncial process. Although distinct structural and functional differences are apparent between ectocytoplasm and perikarya, all of the perikarya along the body of the cestode are morphologically similar, as are all regions of ectocytoplasm. However, immunocytochemically distinct subpopulations of perikarya and regionally defined areas of ectocytoplasm were identified along the tapeworm strobila by the use of monoclonal antibodies raised against a preparation of isolated tegument. The different types of perikarya and the regionally specialized areas of ectocytoplasm were organized in a topographically precise manner along the body of the parasite. Examination of labeling patterns after colchicine treatment suggests that different types of perikarya are specialized for biosynthesis of specific tegumental molecules and for turnover or recycling of tegumental material. Furthermore, it appears that a 52 kDa polypeptide synthesized by one population of perikarya is transported through the syncytium and ultimately resorbed by a different population of tegumental perikarya. These data suggest that the syncytial epidermis of parasitic platyhelminthes exhibits a more complex organization of function than previously appreciated.

Animals↗
PubMed1997

Interconverting gating modes of a nonselective cation channel from the tapeworm Echinococcus granulosus reconstituted on planar lipid bilayers.

A 107-pS (symmetrical 150 mM KCl), nonselective cation channel was reconstituted from a microsomal membrane fraction of the larval stage of the tapeworm Echinococcus granulosus. Most of the time, it displayed a high open probability (>>0.95) irrespective of either the applied voltage, Ca2+, Ba2+, or tetraethylammonium concentration. Nevertheless, in contrast with this "leaklike" behavior, less frequently this "all-the-time-open" channel reversibly entered two different kinetic modes. One of them was characterized by lower Po values and some voltage sensitivity (V(1/2) congruent with 129 mV, and an equilibrium constant for channel closing changing e-fold per 63-mV change) the kinetic analysis revealing that it resulted from the appearance of voltage-sensitivity in the mean closed times and a sixfold increase in the equilibrium constant for channel closing at 0 mV. The other mode was characterized by a very fast open-close activity leading to poorly resolved current levels and a Po around 0.6-0.7 which, occasionally and in a voltage-sensitive manner, entered a long-lived nonconducting state. However, the rare nature of these mode-shifting transitions precluded a more detailed analysis of their kinetics. The conductive properties of the channel were not affected by these switches. Model gating alone does not seem to ensure any physiological role of this channel and, instead, some other channel changes must occur if this phenomenon were to be of regulatory importance in vivo. Thus, mode-shifting might constitute an alternative target for channel activity modulation also in tapeworms.

Animals↗