A new diagnostic tool for neurocysticercosis is a member of a cestode specific hydrophobic ligand binding protein family.
A protein of unknown function has been identified as a key serological tool for diagnosis of human tapeworm neurocysticercosis, a major worldwide neurological disease. Our own sequence analysis predicts that this protein is a member of a newly identified cestode specific oligomeric hydrophobic ligand binding protein family. In this report, using a rat cestode model, we confirm that homologues of this protein can bind fatty acids and their derivatives, and thus suggest a biological function for this key diagnostic tool. (+info)
Complete sequence of the mitochondrial genome of the tapeworm Hymenolepis diminuta: gene arrangements indicate that Platyhelminths are Eutrochozoans.
Using "long-PCR," we amplified in overlapping fragments the complete mitochondrial genome of the tapeworm Hymenolepis diminuta (Platyhelminthes: Cestoda) and determined its 13,900-nt sequence. The gene content is the same as that typically found for animal mitochondrial DNA (mtDNA) except that atp8 appears to be lacking, a condition found previously for several other animals. Despite the small size of this mtDNA, there are two large noncoding regions, one of which contains 13 repeats of a 31-nt sequence and a potential stem-loop structure of 25 bp with an 11-member loop. Large potential secondary structures were identified also for the noncoding regions of two other cestode mtDNAS: Comparison of the mitochondrial gene arrangement of H. diminuta with those previously published supports a phylogenetic position of flatworms as members of the Eutrochozoa, rather than placing them basal to either a clade of protostomes or a clade of coelomates. (+info)
Tapeworm infection reduces epithelial ion transport abnormalities in murine dextran sulfate sodium-induced colitis.
The rat tapeworm Hymenolepis diminuta was used to test the hypothesis that helminth infection could modulate murine colitis. Mice were infected with five H. diminuta cysticercoids, and colitis was evoked via free access to 4% (wt/vol) dextran sulfate sodium (DSS)-containing drinking water for 5 days. BALB/c mice were either infected with H. diminuta and 7 days later exposed to DSS (prophylactic strategy) or started on DSS and infected with H. diminuta 48 h later (treatment strategy). Naive and H. diminuta-only-infected mice served as controls. On autopsy, colonic segments were processed for histological examination and myeloperoxidase (MPO) measurement or mounted in Ussing chambers for assessment of epithelial ion transport. Cytokines (gamma interferon [IFN-gamma], interleukin 12 [IL-12], and IL-10) were measured in serum and colonic tissue homogenates. DSS treatment resulted in reduced ion responses (indicated by short-circuit current [Isc]) to electrical nerve stimulation, the cholinergic agonist carbachol, and the adenylate cyclase activator forskolin compared to controls. H. diminuta infection, either prophylactic or therapeutic, caused a significant (P < 0.05) amelioration of these DSS-induced irregularities in stimulated ion transport. In contrast, the histopathology (i.e., mixed immune cell infiltrate, edema, and ulcerative damage) and elevated MPO levels that accompany DSS colitis were unaffected by concomitant H. diminuta infection. Similarly, there were no significant differences in levels of IFN-gamma, IL-12, or IL-10 in serum or tissue from any of the treatment groups at the time of autopsy. We suggest that abolishment of colitis-induced epithelial ion transport abnormalities by H. diminuta infection provides proof-of-principle data and speculate that helminth therapy may provide relief of disease symptoms in colitis. (+info)
A parasite that increases host lifespan.
Tenebrio molitor is an intermediate host for the rat tapeworm, Hymenolepis diminuta. Parasite oncospheres hatch in the beetle midgut and burrow through into the haemocoel, where they rapidly grow and mature into metacestodes. Repair of damage incurred during invasion and the nutritional demands of the parasites are likely to impose costs on the host. Despite these costs, there is an overall very highly significant difference in survival time (p < 0.001) between infected and control populations of beetles, with a hazard ratio of 2.35 (control versus infected). Infected females showed a 40% increase in survival time to 50% mortality and males showed a 25% increase in survival time to 50% mortality. This parasite-induced increase in host longevity is discussed in the light of changes in resource allocation that may occur in infected beetles. Previous findings have demonstrated that reproductive success is significantly reduced in infected females. The outcome of changes in the reproductive effort made by male beetles is less clear. We suggest that the optimum trade-off between reproduction and longevity may be altered to favour longer host survivorship, which is likely to enhance parasite transmission. (+info)
Thymus dependence of tapeworm (Hymenolepis diminuta) elimination from mice.
Although normal mice eliminated the lumen-dwelling intestinal cestode Hymenolepis diminuta by day 21 post-cysticercoid inoculation, congenitally thymus-deficient (nude) mice maintained their work burdens. Nude mice grafted with thymus glands or injected with thymus cells eliminated their worms. (+info)
Macrophages in protective immunity to Hymenolepis nana in mice.
When mice were treated with carrageenan just before infection with eggs of Hymenolepis nana, they failed to exhibit sterile immunity to the egg challenge, with evidence of a decrease in the number of peripheral macrophages (Mo) and the rate of carbon clearance. Although there were high levels of interleukin-1 (IL-1) released into the intestinal tracts of the parasitized mice at challenge infection, there was almost no release of IL-1 in those treated with carrageenan just before challenge. These results strongly suggest that Mo have an important role in protective immunity to H. nana in mice. (+info)
Hymenolepis diminuta infection in a child living in the urban area of Rome, Italy.
We report a case of Hymenolepis diminuta infection in an Italian child affected by tuberous sclerosis. Praziquantel is the drug of choice for the treatment of H. diminuta infection. However, considering the patient's neurological disease, we decided to use not praziquantel but niclosamide, which proved equally effective. (+info)
Demographic and parasitic infection status of schoolchildren and sanitary conditions of schools in Sanliurfa, Turkey.
BACKGROUND: The design and development of school health programmes will require information at demographic characteristics of schoolchildren and the major health burdens of the school-age group, the opportunities for intervention and the appropriateness of the available infrastructure. This study aims to analyse demographic and parasitic infections status of schoolchildren and sanitary conditions of schools in Sanliurfa province of south-eastern Turkey. METHOD: Three primary schools were randomly selected in the shantytown, apartment and rural districts. A total of 1820 schoolchildren between 7-14 years age were took part to the survey of whom 1120 (61.5%) were boys and 700 (38.4%) were girls. A child form (including child's name, sex, age, school grade and parasitic infections) and school survey form (including condition of water supply, condition of latrines, presence of soaps on the basins and presence of garbage piles around to the schools) were used for demographic, parasitic and sanitary surveys. Stool samples were examined by cellophane thick smear technique for the eggs of intestinal helminths. RESULTS: The demographic survey showed that number of schoolchildren was gradually decreased as their age's increase in shantytown school. The sex ratio was proportional until the second grade, after which the number of females gradually decreased in children in shantytown and rural schools while, in apartment area, schoolchildren was proportionally distributed between age groups and gender even the high-grade students. The prevalence of helminthic infections was %77.1 of the schoolchildren in shantytown, 53.2% in apartment district and 53.1% of rural area. Ascaris lumbricoides was the most prevalent species and followed by Trichuris trichiura, Hymenolepis nana and Taenia species in three schools. Sanitation survey indicated that the tap water was limited in shantytown school, toilet's sanitation was poor, available no soaps on lavatories and garbage piles were accumulated around the schools in shantytown and rural area, while, the school in apartment area was well sanitised. CONCLUSIONS: These results indicated that burden of parasitic infections and poor sanitation conditions constituted public health importance among to the shantytown schoolchildren. School health programmes including deworming and sanitation activities through the health education and improvement of sanitation conditions in the schools have a potential to better health and education for schoolchildren. These programmes also offer the potential to reach significant numbers of population in the shantytown schools with high level of absenteeism. (+info)