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PubMed1987

Hymenolepis diminuta: one of three enteric pathogens isolated from a child.

This article describes a case of enteritis in a 3.5-yr-old child with persistent diarrhea and the isolation of three gastrointestinal pathogens, including a rare human pathogen Hymenolepis diminuta (rat tapeworm). This is the first reported case in the northeastern United States in 20 yr and demonstrates that persons living in homes infested with rodents and arthropods are at risk of acquiring this infection.

Campylobacter Infections↗
PubMed2004

Modelling the spatial distribution of Echinococcus multilocularis infection in foxes.

Alveolar echinococcosis is a rare but fatal disease in humans and is caused by the fox tapeworm Echinococcus multilocularis. The densities of fox and grassland rodent populations and the interactions between them influence E. multilocularis transmission rates in Europe. Successful rabies control has caused fox populations and E. multilocularis prevalence rates to increase in many European countries. The potential increase of the infection pressure on the human population motivates the monitoring of the infection status of foxes over space and time. Detection of E. multilocularis antigen levels in fox faecal samples collected in the field might provide a pragmatic methodology for epidemiological surveillance of the infection status in wildlife hosts across large areas, as well as providing an indication of the spatial distribution of infected faeces contaminating the environment. In this paper, a spatial analysis of antigen levels detected in faeces collected in the Franche-Comté region of eastern France is presented. In Franche-Comté, rodent outbreaks have been observed to originate in areas rich in grassland. Spatial trends in fox infection levels were modelled here as a function of the composition ratio of grassland in the landscape derived from the CORINE land-cover map. Kriging models incorporating the grassland trend term were compared to a variety of models in which five alternative trend expressions were used: the alternative trend expressions included linear and quadratic polynomials on the x and y coordinates with and without a grassland term, and a constant mean model. Leave-one-out cross-validation indicated that the estimation errors of kriging with a trend models were significantly lower when the trend expression contained the grassland index term only. The relationship between observed and predicted antigen levels was strongest when the estimated range of autocorrelation was within the home range size of a single fox. The over-dispersion of E. multilocularis in foxes may therefore account for the majority of spatial autocorrelation locally, while regional trends can be successfully modelled as a function of habitat availability for intermediate hosts.

Animals↗
PubMed2004

Ecological epidemiology: landscape metrics and human alveolar echinococossis.

The larval form of the fox tapeworm Echinococcus multilocularis can cause a potentially fatal liver infection in human hosts. Globally rare, the disease has a high prevalence focus in western China. Recent research has linked landscape to the presence and prevalence of the disease. This paper discusses the epidemiology of E. multilocularis in terms of landscape and disease transmission ecology. Landscape form was defined using satellite imagery to create a land cover classification for a study site in Zhang County (Gansu Province, China). Following the analysis of many landscape metrics, mean shape index was found to be related to the prevalence of infection for 31 villages in 1975 and 1997, at two spatial intervals, suggesting that habitat form is a correlate of disease. A temporal difference shows that the landscape is no longer suitable for transmission. These results indicate the possibility of identifying future hotspots which could aid the management of the disease.

China↗
PubMed2006

Antigens for the immunodiagnosis of Echinococcus granulosus infection: An update.

The taeniid tapeworm Echinococcus granulosus is the causative agent of the echinococcal disease, an important zoonosis with worldwide distribution. Accurate immunodiagnosis of the infection requires highly specific and sensitive antigens to be used in immunodiagnostic assays. The choice of an appropriate source of antigenic material is a crucial point in the improvement of the diagnostic features of tests, and must be based on the developmental stage of the parasite and the host. The most common antigenic sources used for the immunodiagnosis of echinococcal disease are hydatid cyst fluid, somatic extracts and excretory-secretory products from protoscoleces or adults of E. granulosus. Hydatid cyst fluid is the antigenic source of reference for immunodiagnosis of human hydatidosis, which is mainly based on the detection of antigens B and 5. Somatic extracts have been widely used in the serodiagnosis for E. granulosus infection in dogs and ruminant intermediate hosts, although in the last few years the detection of excretory-secretory products of the worm in faeces (coproantigens) have become the most reliable method for the detection of the parasite in the definitive host. This review emphasizes recent advances in the identification and characterization of novel antigens with potential for the immunodiagnosis of echinococcal disease. Progress in recombinant technologies and synthetic peptides are also discussed. The paper highlights the need to search for new antigenic components with high diagnostic sensitivity and specificity, a fact that remains a crucial task in the improvement of the immunodiagnosis of the disease.

Animals↗
PubMed2006

Taeniasis/cysticercosis in a Tibetan population in Sichuan Province, China.

The results of a preliminary survey of taeniasis/cysticercosis in Yajiang County, Ganze Tibetan Prefecture in southwest Sichuan Province, China, indicated a very high prevalence of taeniasis (22.5%), with Taenia saginata as the dominant species. There was also a significant occurrence of late-onset epilepsy (8.5% prevalence and 16.4% seropositive for Taenia solium antibodies) attributable in large part to probable neurocysticercosis caused by T. solium. The poor sanitation and hygiene in this Tibetan community likely contributed to a high risk of human cysticercosis despite a low level of T. solium taeniasis (actually no T. solium carriers were detected amongst the 21 proven Taenia carriers). In addition, three taeniasis cases were confirmed by DNA genotyping as Taenia asiatica, which is the first report of this tapeworm in Tibetans, the first report for Sichuan Province and only the third report for mainland China.

Adolescent↗
PubMed2005

Parasitism in fish--an endocrine modulator of ecological relevance?

Wild bream (Abramis brama) were collected from the river Elbe, and the influences of parasitic infection by the tapeworm Ligula intestinalis on endocrine and related functions (vitellogenin [VTG]; plasma sex steroids: 17beta-estradiol [E2], 11-ketotestosterone [11-KT] and testosterone [T]; relative gonad [GSI] and liver [HSI] growth; maturation stages of germ cells [MS]; prominence of spawning tubercles [STI]) were investigated. Distinct regional differences in infection rates of bream with L. intestinalis were observed along the Elbe with the highest prevalences at the Czech border (up to 45%) and Magdeburg (up to 65%), areas that are heavily contaminated with complex mixtures of organic chemicals and metals. Parasitized fish of both sexes had significantly lower GSIs and poorly developed gonads (low MS). In males, a significant reduction in the prominence of spawning tubercles occurred. Infected females had significantly lower plasma VTG concentrations. A selective suppression of the sex steroids 11-KT and E2 was observed in male and female bream, respectively. Testosterone was not affected in the same manner in fish of both sexes. At sites with an elevated prevalence of L. intestinalis, the extent of the infection of an individual was significantly correlated with the suppression of the measured biomarkers. However, when applying a linear model to compare regional differences in infection prevalence with biological parameters, not all of the observed differences could be explained by parasitization by L. intestinalis. This indicates that other factors such as pollution may have contributed to the effects on reproductive and endocrine processes that occurred along the river. Given that sites with high prevalences of L. intestinalis were also characterized by elevated pollution, it is possible that there exists a combinatory effect of both pollution and parasitization that can have a serious impact on the reproductive capacity of a population, such as was observed at the sampling site at Magdeburg.

Animals↗
PubMed2006

Oral cysticercosis.

Cysticercosis is the result of infection with the larval stage of the tapeworm, Taenia solium. The parasite may settle at any site in the body without causing symptoms, which arise almost exclusively from the involvement of brain or eye, and this may occur several years after infection. Cysticercosis is one of the leading causes of acquired epilepsy in Latin America, parts of Asia, and Africa. More cases are being reported in other countries as a result of immigration from endemic areas. Cysticercosis may cause cystic swellings or nodules in the mouth, and these may be the only evidence of the disease. We present a healthy patient who had multiple intraoral cystic swellings that were diagnosed as cysticercosis in a biopsy specimen. Subsequent investigations showed cysticerci in the brain.

Adult↗
PubMed2004

Effects of phytochemicals of Flemingia vestita (Fabaceae) on glucose 6-phosphate dehydrogenase and enzymes of gluconeogenesis in a cestode (Raillietina echinobothrida).

The crude root-peel extract of Flemingia vestita, containing genistein as the major isoflavone, has a vermifugal/vermicidal effect. It acts by causing flaccid paralysis accompanied by alterations in the activities of several tegumental enzymes and other metabolic activities in the fowl tapeworm, Raillietina echinobothrida. To elucidate the mode of action of the putative phytochemicals on energy metabolism, crude root-peel extract, pure genistein and praziquantel were tested on glucose 6-phosphate dehydrogenase (G6PDH) and enzymes of gluconeogenesis--pyruvate carboxylase (PC), phosphoenolpyruvate carboxykinase (PEPCK) and fructose 1,6-bisphosphatase (FBPase)--in R. echinobothrida. The activities of G6PDH, PEPCK and FBPase were largely restricted to the cytosolic fraction, while PC was confined to the mitochondrial fraction. Following treatments, the G6PDH activity was decreased by 23-31%, whereas the activities of PC and PEPCK were increased by 32-44% and 44-49%, respectively. There was no significant effect by any of the treatments on FBPase activity. We hypothesize that the phytochemicals from F. vestita, genistein in particular, influence the key enzymes of these pathways, which is perhaps a function of high energy demand of the parasite under anthelmintic stress.

Animals↗
PubMed2006

Advances in liver echinococcosis: diagnosis and treatment.

Echinococcosis or hydatid cyst disease is a zoonosis caused by the larval cestode Echinococcus granulosus. It consists of a parasitic tapeworm disease affecting mainly liver. Nevertheless, the disease might well spread to more unusual sites such as lungs and brain. The definitive diagnosis of liver echinococcosis requires a combination of imaging, serologic, and immunologic studies. Despite the fact that a number of scolecoidal agents have been developed against liver hydatid disease, the cornerstone of the definitive treatment remains surgery. Both the classic surgical techniques and the recently developed minimally invasive and laparoscopic methods target the eradication of the disease by simultaneously avoiding perioperative spillage and dissemination or recurrence of echinococcosis. The present article constitutes a review of the biology of the parasite as well as the epidemiology, diagnosis, and therapeutic options of the liver hydatid disease.

Algorithms↗
PubMed2006

Suppression of aromatase activity in populations of bream (Abramis brama) from the river Elbe, Germany.

Aromatase activity was determined in brain and gonads of wild bream collected along the river Elbe, Germany, and correlated with other endocrine and reproductive endpoints such as plasma sex steroid concentrations, secondary sex characteristics (STI), plasma vitellogenin, gonad size (GSI), and maturation stages of germ cells (MS) that were reported for the same fish in a previous study. Furthermore, regional patterns of aromatase activity were correlated to a number of environmental factors such as exposure to environmental contaminants and parasitism. While aromatase activity was not detectable in the gonads of male and female fish with the assay used, fish of both genders revealed relatively great brain enzyme activities. As for most of the endocrine and reproductive parameters, with the exception of plasma testosterone (T), aromatase activities were significantly less in fish from a river stretch characterized by elevated exposures to organic contaminants and metals. Brain aromatase activity was positively and significantly correlated with plasma estradiol (E2) and MS in females, and showed a similar trend with plasma 11-ketotestosterone (11KT) and STI in males. No comparable trend occurred for T. This decrease of the reproductively relevant hormones 11KT and E2 may be indicative of a disruption of the last step in sex hormone synthesis, a hypothesis that was supported for E2 by the strong (R2=0.78, p<0.05) linear regression between aromatase activity and E2 in female bream. It is also hypothesized that the effects on brain aromatase activity were likely to be related to the disruption of other reproductive parameters including sexual maturity and expression of secondary sex characteristics. Although a number of factors such as exposure to pollutants and prevalence of the tapeworm Ligula intestinalis correlated with the suppression of aromatase activity, the exact causes for the regional decrease in brain aromatase activity remain unclear due to inconsistencies of these correlations between sampling events or gender.

Animals↗
PubMed2004

Echinococcus granulosus in Jordan: assessment of various antigenic preparations for use in the serodiagnosis of surgically confirmed cases using enzyme immuno assays and the indirect haemagglutination test.

The Enzyme linked immunosorbent Assay (ELISA), indirect haemagglutination (IHA), and immunoblot techniques (IB) were used for the serodiagnosis of surgically confirmed cystic echinococcosis (CE) caused by the tapeworm Echinococcus granulosus. Antigens used for the detection of IgG or total antibodies included crude sheep hydatid fluid (CSHF), autoclaved antigen B (AAB), boiled antigen B (BAB), and homogenate protoscoleces antigen (HPA). The overall sensitivity of the ELISA and IHA tests used for the serodiagnosis of 57 surgically confirmed human cases was 91.2% and 68.4%, respectively. The sensitivity of both tests was comparable in groups whose sera were collected one week before surgery and up to one year after surgery at 95.8% and 87.5%, respectively. In contrast, the sensitivity of the ELISA was significantly higher than that of IHA for sera of patients collected after one year of surgery. There was a positive correlation (r = 0.61) between the titers of antibodies detected by the ELISA and IHA. Using the IB technique, antigen B fractions (8/12, 16, and 24 KDa) were detectable by sera of 68.4% using either CSHF or AAB, 49.1% using BAB and 22.8% using HPA as detecting antigens. The overall sensitivity of the three AgB fractions was identical or similar to that of the 8/12 KDa fraction alone, indicating that the detection of the latter fraction is sufficient for the serodiagnosis of CE infection in humans. In conclusion, the ELISA is the test of choice for the serodiagnosis of CE and the follow up of cases following surgery using CSHF as an antigen. The IB test is a confirmatory test when antigen B fractions of CSHF or AAB are detected.

Adult↗
PubMed2005

Echinococcus multilocularis: cloning and characterization of a member of the SNW/SKIP family of transcriptional coregulators.

We have isolated a cDNA from the fox-tapeworm Echinococcus multilocularis that encodes EmSkip, a novel member of the SNW/SKIP family of transcriptional coregulators. EmSkip displays significant amino acid sequence homologies to already known members of the protein family and contains all the characteristic amino acid residues at their corresponding positions. RT-PCR experiments showed that the EmSkip encoding gene, emskip, is expressed in the Echinococcus larval stages metacestode and protoscolex during an infection of the intermediate host. By yeast two-hybrid analyses, EmSkip was found to be capable of forming homodimers in vivo. Furthermore, EmSkip was found to interact with EmSmadA and EmSmadB, two previously identified TGF-beta/BMP signal transducers of E. multilocularis, indicating a role of this protein in TGF-beta signaling processes in the parasite. In view of the role played by SNW/SKIP proteins in splicing mechanisms and intracellular signaling, the data presented herein should facilitate the identification of Echinococcus factors involved in such processes.

Amino Acid Sequence↗
PubMed2004

A Bayesian approach for estimating values for prevalence and diagnostic test characteristics of porcine cysticercosis.

Several diagnostic techniques are used to estimate the prevalence of the zoonotic tapeworm Taenia solium in pigs, but none of these tests are perfect, making interpretation of results difficult. A Bayesian approach was used to estimate values for the prevalence and diagnostic test characteristic of porcine cysticercosis by combining results of four imperfect tests. Village pigs (N = 868) slaughtered in Lusaka (Zambia), were bled, and tongue and routine meat inspected; and serum antibody and parasite antigen concentrations were determined by ELISA. A model, based on a multinomial distribution and including all possible interactions between the individual tests required 31 parameters to be estimated, but actually allowed only 15 parameters (i.e. had 15 degrees of freedom) to be estimated. Therefore, prior expert opinion on specificity and (in)-dependence of the tests was entered in the model, resulting in a reduction of the number of parameters to be estimated. The estimated prevalence of porcine cysticercosis was 0.642 (95% confidence interval 0.54-0.91). The performances of the tests were (sensitivity (se)-specificity (sp)): tongue inspection (se 0.210-sp 1.000), meat inspection (se 0.221-sp 1.000), Ab-ELISA (se 0.358-sp 0.917), Ag-ELISA (se 0.867-sp 0.947). To validate the estimates obtained from the model we performed a second study: 65 randomly purchased Zambian village pigs were bled for serum antibody and antigen determination, their tongue and meat inspected; and in addition, the carcasses were dissected for total cysticercus counts (gold standard). Cysticerci were found in 31 pigs (prevalence 0.477, 95% confidence interval 0.35-0.60), overlapping with the estimated prevalence in the first study. Sensitivity and specificity values obtained for the aforementioned tests in this study were in agreement with those estimated. A Bayesian analysis framework offers the possibility to combine prior opinion with experimental data to more accurately estimate the real prevalence of porcine cysticercosis in the absence of a gold standard.

Animals↗
PubMed2005

Hydatid control in Australia: where it began, what we have achieved and where to from here.

Echinococcus granulosus was imported into Australia with domestic livestock about 200 years ago. It spread rapidly through domestic animals and quickly became a public health problem in the new colony. Control was hampered by ignorance of the transmission pattern. The association between metacestodes and tapeworms was not elucidated until 63 years after the arrival of the First Fleet. Australian wildlife were highly susceptible to infection with E. granulosus and wildlife/domestic animal interaction facilated rapid infiltration of wildlife by E. granulosus. The wildlife reservoir has hampered hydatid control campaigns on mainland Australia but successful eradication has been achieved in the island state of Tasmania where there was no wildlife reservoir. The application of a new recombinant vaccine for sheep in control campaigns and the use of praziquantel baits for controlling infection in dingoes around bush campsites and picnic areas is discussed.

Animals↗
PubMed2006

Voltage-gated calcium channel subunits from platyhelminths: potential role in praziquantel action.

Voltage-gated calcium (Ca2+) channels provide the pathway for Ca2+ influxes that underlie Ca2+ -dependent responses in muscles, nerves and other excitable cells. They are also targets of a wide variety of drugs and toxins. Ca2+ channels are multisubunit protein complexes consisting of a pore-forming alpha(1) subunit and other modulatory subunits, including the beta subunit. Here, we review the structure and function of schistosome Ca2+ channel subunits, with particular emphasis on variant Ca2+ channel beta subunits (Ca(v)betavar) found in these parasites. In particular, we examine the role these beta subunits may play in the action of praziquantel, the current drug of choice against schistosomiasis. We also present evidence that Ca(v)betavar homologs are found in other praziquantel-sensitive platyhelminths such as the pork tapeworm, Taenia solium, and that these variant beta subunits may thus represent a platyhelminth-specific gene family.

Amino Acid Sequence↗
PubMed2006

Toxicological study on Glinus lotoides: a traditionally used taenicidal herb in Ethiopia.

Seeds of Glinus lotoides L. (Molluginaceae) are used traditionally in the treatment of tapeworm infestation in Ethiopia. Previous studies on its anthelmintic activities confirmed its traditional claims, but data on safety profile were lacking. To this effect, single and repeated dose oral toxicities of the methanolic extracts of seeds of Glinus lotoides were conducted in rats. Doses of 0, 1000 and 5000 mg/kg of crude extract of Glinus lotoides were employed in single dose toxicity studies, while doses of 0, 250, 500, and 1000 mg/kg were used in repeated toxicity studies. In the single dose toxicity test, oral administration of 5000 mg/kg of Glinus lotoides produced mortality in two females and one male on day 4. No significant differences in body and organ weights were observed between controls and treated surviving animals. Moreover, both gross and microscopic examinations of organs did not show detectable differences between controls and treated animals of both sexes. In repeated dose toxicity studies, no mortality was observed when varying doses of the extracts were administered per day for a period of 28 days. There were no significant differences in body weight, absolute and relative organ weights between controls and treated animals of both sexes. Hematological analysis showed no differences in most parameters examined. In the biochemistry parameter analysis, no significant change occurred. Pathologically, neither gross abnormalities nor histopathological changes were observed. These finding suggest that none of the organs appeared to be target and the data could provide satisfactory preclinical evidence of safety to launch clinical trial on standardized formulation of plant extracts.

Administration, Oral↗
PubMed2004

Jejunal perforation caused by morphologically abnormal Taenia saginata saginata infection.

We report a case of jejunal perforation caused by infection with taeniid tapeworm possessing unusual morphology that has not been previously described. Among five cestodes recovered during operation, one exhibited a bifurcation at the posterior end and the other harbored a lateral branching of immature segments from the main strobila. By sequence analysis of the mitochondrial cytochrome c oxidase I gene and the 28S rRNA gene has confirmed them to be Taenia saginata saginata.

Adult↗
PubMed2004

Apoptosis in the fat body tissue of the beetle Tenebrio molitor parasitised by Hymenolepis diminuta.

Many insects experience a decrease in reproductive output when parasitised. We are investigating mechanisms underlying this fecundity reduction using the rat tapeworm, Hymenolepis diminuta infection of Tenebrio molitor beetles. These include an increase in the resorption of developing ovarian follicles and a decrease in fat body synthesis of vitellogenin. The latter is the direct effect of a molecule produced by the parasite. Here we report a study to determine whether vitellogenin synthesis and follicle resorption are the result of parasite-induced apoptosis in the respective tissues and whether the parasite molecule acts directly on the fat body by inducing apoptosis. In vivo, the number of fat body cell nuclei with chromatin condensation are significantly elevated in parasitised females at all days examined and peaked at day 7 post-infection. A TUNEL assay to detect DNA fragmentation confirmed these observations of apoptosis. However, when fat body from uninfected females was co-cultured with live metacestodes they did not cause cells to die by apoptosis, showing that the induction signal does not come directly from the parasite. The follicle resorption observed in the ovaries of infected beetles was not associated with apoptosis of the epithelial cells. The possibility of several mechanisms underlying fecundity reduction is discussed.

Adipose Tissue↗