Schistosomiasis

Lethal and sub-lethal effects of UVB on juvenile Biomphalaria glabrata (Mollusca: Pulmonata)

Although Schistosoma mansoni occurs mainly in the tropics, where intense levels of solar radiation are present, the impact of ultraviolet (UV) light on schistosome transmission is not known. The purpose of this study was to investigate potential effects of UVB (290-320nm) on juvenile Biomphalaria glabrata, the snail intermediate host of S. mansoni. Albino and wild-type snails were exposed to doses of UVB from UV-fluorescent lamps, and the following were measured: survival, photoreactivation (light-mediated DNA repair), effects on feeding behavior, and morphological tissue abnormalities. Irradiation with UVB is lethal to B. glabrata in a dose-dependent manner. Exposure to white light subsequent to UVB irradiation enhances survival, probably by photoreactivation. The shell offers some, but not complete, protection. Experiments in which UVB transmittance through the shell was blocked with black nail polish suggest that injury to both exposed (headfoot) and shell-enclosed (mantle and visceral mass) tissues contributes to mortality in lethally irradiated snails. Wild-type (pigmented) snails are less susceptible to lethal effects of UVB than albino snails, and they may be more capable of photoreactivation. UVB exposure inhibits snail feeding behavior, and causes tentacle forks and growths on the headfoot. Thus, UVB may influence the life cycle of S. mansoni by both lethal and sub-lethal damage to the snail intermediate host. However, the ability of snails to photoreactivate may mitigate these effects.

Serum and cerebral spinal fluid levels of chemokines and Th2 cytokines in Schistosoma mansoni myeloradiculopathy

Schistosomal myeloradiculopathy (SMR) is the most common neurological form of Schistosoma mansoni infection. In this study we investigated the expression of chemokines and Th2 cytokines in serum and cerebral spinal fluid (CSF) of SMR patients. SMR patients presented increased serum levels of CCL11/eotaxin and CCL24/eotaxin-2 when compared to controls. SMR patients also had higher levels of IL-13 in CSF. Thus, SMR patients present enhancement of both IL-13 and CCR3 acting chemokines, both of which may facilitate the expression of a Th2 response and Th2-dependent damage to the spinal cord. As this cytokine is responsible for promoting Th2 responses, this finding is in accordance to the view that Th2 cells are important in the immunological process against the S. mansoni.

Aberrant receptor-mediated endocytosis of Schistosoma mansoni glycoproteins on host lipoproteins

BACKGROUND

Bilharzia is one of the major parasitic infections affecting the public health and socioeconomic circumstances in (sub) tropical areas. Its causative agents are schistosomes. Since these worms remain in their host for decades, they have developed mechanisms to evade or resist the immune system. Like several other parasites, their surface membranes are coated with a protective layer of glycoproteins that are anchored by a lipid modification.

METHODS AND FINDINGS

We studied the release of glycosyl-phosphatidylinositol (GPI)-anchored proteins of S. mansoni and found them in the circulation associated with host lipoprotein particles. Host cells endocytosed schistosomal GPI-anchored proteins via their lipoprotein receptor pathway, resulting in disturbed lysosome morphology. In patients suffering from chronic schistosomiasis, antibodies attacked the parasite GPI-anchored glycoproteins that were associated with the patients' own lipoprotein particles. These immunocomplexes were endocytosed by cells carrying an immunoglobulin-Fc receptor, leading to clearance of lipoproteins by the immune system. As a consequence, neutral lipids accumulated in neutrophils of infected hamsters and in human neutrophils incubated with patient serum, and this accumulation was associated with apoptosis and reduced neutrophil viability. Also, Trypanosoma brucei, the parasite that causes sleeping sickness, released its major GPI-anchored glycoprotein VSG221 on lipoprotein particles, demonstrating that this process is generalizable to other pathogens/parasites.

CONCLUSIONS

Transfer of parasite antigens to host cells via host lipoproteins disrupts lipid homeostasis in immune cells, promotes neutrophil apoptosis, may result in aberrant antigen presentation in host cells, and thus cause an inefficient immune response against the pathogen.

Assessment of portal hemodynamics by Doppler ultrasound and of liver morphology in the hepatosplenic and hepatointestinal forms of schistosomiasis mansoni

The aim of this study was to compare portal and splenic blood flows and the liver morphology in hepatosplenic (HS) and hepatointestinal (HI) schistosomiasis. Doppler ultrasound measurements were performed in 48 adult patients with schistosomiasis, according to the criteria of the World Health Organization, and compared with those performed in 20 healthy controls. Portal flow was significantly higher (P < 0.0001) in both HS and HI (2481 +/- 1467 and 2159 +/- 1446 ml/min, respectively) than in normal individuals (842 +/- 322 ml/min). There was no difference in splenic blood flow (822 +/- 685 and 458 +/- 292 ml/min, respectively) between HS and HI, but these values were significantly higher than those of normal controls (243 +/- 94 ml/min). Portal and splenic overflow are found in both the HS and the HI forms of schistosomiasis.

Herbimycin A suppresses mitotic activity and egg production of female Schistosoma mansoni

The eggs of the endoparasite Schistosoma are the causative agent of schistosomiasis, an important disease of humans, which is endemic in (sub-) tropical regions. The absence of a vaccine with sufficient protective qualities and increasing resistance to approved and established drugs like praziquantel, justify the exploration of novel ways to fight schistosomes. Our strategy is based on interference with the sexual maturation of the female. Prerequisites for gonad development in adult females are a continuous pairing contact with the male and significantly increased mitotic activity. In this study we show that the male governs sexual maturation of the female, as the separation of couples causes a clear reduction of female mitotic activity and, consequently, egg production. We demonstrate that treatment of schistosomes with Herbimycin A, an inhibitor of protein tyrosine kinases (PTKs), mimics the separation of couples as the drug blocks mitotic activity and egg production of paired females. However, the synthesis of the eggshell precursor protein p14 is elevated. Furthermore, we show for the first time in invertebrates that Herbimycin A decreases tyrosine phosphorylation and PTK stability in schistosomes. Summarised, our data provide evidence that PTKs have key functions in regulating gonad development, eggshell gene expression and, consequently, egg production. Therefore, we suggest envisaging schistosome PTKs as novel targets for strategies to combat schistosomiasis.

[Acute schistosomiasis in French travellers]

OBJECTIVE

The clinical presentation of acute schistosomiasis in travellers differs from those observed with chronic schistosomiasis in people from endemic areas. The objective of this study is to describe the main clinical and biological characteristics of the acute schistosomiasis in French travellers.

METHODS

Retrospective study conducted in 42 hospital laboratories of parasitology in France, based on a questionnaire filled out for each case of schistosomiasis diagnosed in subjects non-originating from an endemic country and returning from of a stay in Africa, between 2000 and 2004.

RESULTS

Seventy-seven cases of acute schistosomiasis diagnosed between 2000 and 2004 were reported by 15 of the 33 laboratories having taken part in the study. The patients were 26 years old on average and 60% were contaminated in West Africa. Seventy patients (91%) presented at least one symptom at the moment of the diagnosis, but only 44 (57%) presented sufficiently intense symptoms to justify a medical consultation spontaneously. The most frequently reported clinical signs were fever (44%), diarrhoea (40%), pruritus (25%), cough (21%) and hematuria (20%). Hypereosinophilia (82%), elevated liver enzymes and positive serology were respectively reported in 82, 23 and 90% of the cases. Ova were found in the urines or the stool in 60% of the cases. Eleven patients were hospitalized.

DISCUSSION

Acute schistosomiasis must be evoked in patients returning from endemic country and presenting with non-specific symptoms; including patients whose bathes in contaminated water was limited to a short contact of the feet in a river. The high frequency of the asymptomatic or paucisymptomatic forms exposes the infected people to a delayed diagnosis and therefore to an evolution towards the chronic form of schistosomiasis. The increase in tourism towards the endemic areas could be accompanied by an increase in the frequency of the schistosomiasis, and encourages setting-up an active monitoring of acute schistosomiasis.

Identification of inhibitors of ribozyme self-cleavage in mammalian cells via high-throughput screening of chemical libraries

We have recently described an RNA-only gene regulation system for mammalian cells in which inhibition of self-cleavage of an mRNA carrying ribozyme sequences provides the basis for control of gene expression. An important proof of principle for that system was provided by demonstrating the ability of one specific small molecule inhibitor of RNA self-cleavage, toyocamycin, to control gene expression in vitro and vivo. Here, we describe the development of the high-throughput screening (HTS) assay that led to the identification of toyocamycin and other molecules capable of inhibiting RNA self-cleavage in mammalian cells. To identify small molecules that can serve as inhibitors of ribozyme self-cleavage, we established a cell-based assay in which expression of a luciferase (luc) reporter is controlled by ribozyme sequences, and screened 58,076 compounds for their ability to induce luciferase expression. Fifteen compounds able to inhibit ribozyme self-cleavage in cells were identified through this screen. The most potent of the inhibitors identified were toyocamycin and 5-fluorouridine (FUR), nucleoside analogs carrying modifications of the 7-position and 5-position of the purine or pyrimidine bases. Individually, these two compounds were able to induce gene expression of the ribozyme-controlled reporter approximately 365-fold and 110-fold, respectively. Studies of the mechanism of action of the ribozyme inhibitors indicate that the compounds must be incorporated into RNA in order to inhibit RNA self-cleavage.

Lumbar Intramedullary Spinal Schistosomiasis Presenting as Progressive Paraparesis: Case Report

OBJECTIVE AND IMPORTANCE:

Blood fluke infection or schistosomiasis affects up to 300 million people worldwide. Although infection of the hepatic and urogenital systems commonly occurs, central nervous system involvement is rare. When presenting in the spinal cord, schistosomiasis can be difficult to diagnose because it can present as mass lesion or transverse myelitis. We describe a patient with lumbar intramedullary spinal schistosomiasis who presented to a tertiary medical center in the United States and discuss the diagnosis and treatment of this rare disease.

CLINICAL PRESENTATION:

A 25-year-old Brazilian man presented with progressive, subacute, bilateral lower extremity motor and sensory deficits and disturbances in bladder function. Magnetic resonance imaging revealed a diffusely enhancing mass expanding the region of the conus medullaris.

INTERVENTION:

Laboratory investigation disclosed serum and cerebrospinal fluid eosinophilia. Ultimately, cerebrospinal fluid serology demonstrated the presence of Schistosoma mansoni. The patient was treated with praziquantel and steroids and made a marked recovery.

CONCLUSION:

The clinical and radiographic manifestations of spinal schistosomiasis can mimic those of intra-axial spinal tumors and transverse myelitis. To avoid unnecessary surgery or delay in treatment, the clinician must have knowledge of this type of presentation. The increasing volume of international travel and high prevalence of the disease worldwide increases the possibility that the practicing neurosurgeon in the United States may encounter this rare but treatable disease.

Schistosomiasis--a century searching for chemotherapeutic drugs

Schistosomiasis affects 200 million individuals in underdeveloped and developing regions and is a growing concern for travelers worldwide. There has been evidence of resistance to the praziquantel-based therapy and reports of acute-disease manifestation; therefore, other drugs affecting different stages of the schistosome parasites life cycle and alternative therapeutic regimens should be developed and become accessible. The present review results from a comprehensive search in the scientific literature for substances and compounds tested in the past centennial for schistosomiasis therapy. We gathered over 40 drugs providing information on therapeutic action in humans or animal model, toxicity, susceptible Schistosoma stages, species, etc. The drugs were grouped according to their known metabolic effects on the parasite, whether they are on membrane structure and function, carbohydrate metabolism, protein synthesis and function, or on nucleic acid metabolism. We discuss the current knowledge of drug-target interactions, their mechanism of action and possible therapy combinations. Furthermore, based in the literature and in our own experience with large-scale Schistosoma mansoni genome and transcriptome analyses, we put forward several recently described gene products that are promising target candidates for existing or new drugs.

Transcriptomics tool for the human Schistosoma blood flukes using microarray gene expression profiling

We report the design, fabrication, and validation of a microarray covering the majority of the Schistosoma japonicum and Schistosoma mansoni transcriptomes. The oligonucleotide microarray contains 12,166 S. mansoni and 7055 S. japonicum target sequences. A confidence threshold of <or=0.001 (P value) was used in all analyses. The cross hybridization potential of the microarray was representative of 10,362 probes detected in both channels, while 12,052 probes hybridised to S. japonicum and 11,254 probes hybridised to S. mansoni. Differential hybridisation consisted of 3422 probes to S. mansoni mRNA and 3103 probes to S. japonicum mRNA. Important biological functions, such as transport, metabolism, immune evasion and host-parasite immunological interplay, cell communication, and sexual maturation are represented on this microarray. This is the first microarray commercially manufactured for studying schistosomes, and the large size and verified quality of the resource demonstrate its power for characterising the schistosome transcriptome.

Oligonucleotide microarray analysis of strain- and gender-associated gene expression in the human blood fluke, Schistosoma japonicum

Schistosomiasis is a chronic and debilitating disease caused by blood flukes (digenetic trematodes) of the genus Schistosoma. Schistosomiasis japonica, a zoonosis caused by Schistosoma japonicum, is endemic to the Philippines and China. We utilised a 22,575 feature custom oligonucleotide DNA microarray designed from public domain databases of schistosome-expressed sequence tags to explore differential gene expression between the Philippine (SJP) and Chinese (SJC) strains of S. japonicum, and between male and female S. japonicum. We found that 593, 664 and 426 probes were differentially expressed between the two geographical strains when we compared mix sexed adults, male worms and female worms. Additionally, the study revealed that 1163 male- and 1016 female-associated probes were differentially expressed in SJP whereas 1047 male- and 897 female-associated probes were differentially expressed in SJC. The study greatly expands previously published data of strain and gender-associated differential expression in S. japonicum. Further, these new data provide a stepping stone for understanding the complexities of the biology, sexual differentiation, maturation, and development of human schistosomes, signaling new approaches for identifying novel intervention and diagnostic targets against schistosomiasis.

EAU guidelines for the management of urogenital schistosomiasis

More than 100 million people worldwide are affected by bilharziasis, caused by Schistosoma haematobium. For travellers precaution is most important. For the population in endemic areas, an integrated approach including health education is necessary. Effective pharmacologic treatment is available.

Recombinant tegumental protein Shistosoma japonicum very lowdensity lipoprotein binding protein as a vaccine candidate against Schistosoma japonicum

A polyhistidine-tagged recombinant tegumental protein Schistosoma japonicum very lowdensity lipoprotein binding protein (SVLBP) from adult Schistosoma japonicum was expressed in Escherichia coli. The affinity purified rSVLBP was used to vaccinate mice. The worm numbers and egg deposition recovered from the livers and veins of the immunized mice were 33.5% and 47.6% less than that from control mice, respectively (p<0.05). There was also a marked increase in the antibody response in vaccinated mice: the titer of IgG1 and IgG2a, IgG2b in the vaccinated group was significantly higher than that in the controls (>1:6,400 in total IgG). In a comparison of the reactivity of sera from healthy individuals and patients with rSVLBP, recognition patterns against this parasite tegumental antigen varied among different groups of the individuals. Notably, the average titres of anti-rSVLBP antibody in sera from faecal egg-negative individuals was significantly higher than that in sera from the faecal egg-positives, which may be reflect SVLBP-specific protection. These results suggested that the parasite tegumental protein SVLBP was a promising candidate for further investigation as a vaccine antigen for use against Asian schistosomiasis.

Small bowel obstruction secondary to intestinal schistosomiasis

Intestinal obstruction caused by chronic schistosomiasis infection is rare, with only 12 previously recorded cases in the literature. We report the first recorded case presenting to a European hospital. A 36-year-old Caucasian man, who was born and lived in the UK, presented with small bowel obstruction. He had visited China and Indonesia 8 years previously. At laparotomy, there was an obstructing inflammatory mass close to the ileocaecal junction and several small bowel strictures. Initially he was thought to have Crohn's disease. However, subsequent histology diagnosed intestinal schistosomiasis.

Schistosoma japonicum: the design and experimental evaluation of a multivalent DNA vaccine

The aim of this study was to construct and evaluate the immunity efficacy of the DNA multivalent vaccine pVIVO(2)SjFABP-23. The vaccine was constructed and produced as follows. Forty BALB/c mice were divided into four groups designated pVIVO(2), pVIVO(2)Sj23, pVIVO(2)SjFABP and pVIVO(2)SjFABP-23. Each mouse was immunized with 100 mug of the corresponding plasmid DNA by intramuscular injection. 28 days post-vaccination, the mice were challenged with S. japonicum cercariae, and the worm and egg burdens were determined 42 days post-challenge. Serum samples were collected from all the mice before and after vaccination and at the end of the experiment, and used for antibody detection. The IFN-gamma and IL-4 levels were quantified in the supernatants of specifically stimulated spleen cells. The number of worms was reduced by 52%, 40% and 42% in mice respectively immunized with pVIVO(2)SjFABP-23, pVIVO(2)Sj23 or pVIVO(2)SjFABP. A respective 61%, 38% and 39% egg reduction was determined relative to those mice that only received the empty pVIVO2 plasmid. pVIVO(2)SjFABP-23 immunization increased IgG levels against SWAP and SEA. Increased IFN-gamma levels were detected in the supernatant of specific stimulated spleen cells from mice immunized with the 3 different constructs. The multivalent DNA vaccine developed induced higher levels of protection than the two monovalent tested vaccines.

The effect of a mutagen (N-methyl-N-nitro-N-nitrosoguanidine) on cultured cells from adult Schistosoma japonicum

The transforming effect of N-methyl-N-nitro-N-nitrosoguanidine (MNNG) on cultured cells from Schistosoma japonicum (S. japonicum) was studied using mono-factor and orthogonal tests. Under the influence of MNNG, cultured cells grew well, and cell survival time was more than 246 days in low-serum medium. When treated with 3 mug/ml MNNG for 48 h, the number of dividing cells increased significantly as determined by bright-field and scanning electron microscopy (SEM). Under these conditions, abundant microvilli, ruffles, microridges, papillae and blebs were observed on the surface of the induced cells. Treatment with MNNG may overcome existing limitations to get continually proliferating schistosome cells and open the possibility to immortalize isolated cells.

Bilharzioses invasives

Schistosomiasis is a tropical helminthic infection, observed in travelers as well as local populations. It is most often due to Schistosoma mansoni or Schistosoma haematobium and can be diagnosed at the invasive phase. Migration of the schistosomulae (larvae) in the body leads to acute parasitic toxemia, which includes a hypersensitivity reaction and circulating immune complexes. The invasive stage occurs generally 2 to 6 weeks after the exposure and combines fever, asthenia, faintness and headaches. Other signs include diarrhea, dry cough, dyspnea, urticarial rash, arthralgia, myalgia, and enlargement of liver and spleen. Although rare, neurological and cardiac complications may be fatal. This diagnosis should be considered in travelers returning from the tropics with compatible clinical signs and delayed hypereosinophilia, if they report exposure in an endemic area. It is later confirmed by seroconversion for schistosomiasis and then by observation of schistosome eggs in stool or urine (according to species). The standard treatment of acute schistosomiasis with praziquantel is ineffective and can aggravate clinical outcome during this phase. Corticosteroid treatment is recommended for serious forms with neurological or cardiac manifestations.

A double-blind field trial on the effects of artemether on Schistosoma japonicum infection in a highly endemic focus in southern China

To further strengthen the evidence-base of artemether for the control of schistosomiasis japonica, a randomised controlled trial was carried out in the Poyang Lake region, a highly endemic area in southern China. A total of 783 individuals, aged 6-60 years, were enrolled. They were first given a single oral dose of praziquantel (50 mg/kg). Then, they were randomly assigned oral artemether (6 mg/kg) or placebo, administered once every 2 weeks for 9-11 doses, covering the entire transmission season for Schistosoma japonicum in 2004. Stool examination 1 month after the final dosing revealed eggs of S. japonicum in 3/373 (0.8%) of the artemether recipients and 56/361 (15.0%) in placebo recipients (chi2=53.69, P<0.001). Compared to the baseline, the geometric mean intensity of S. japonicum infection had decreased by 96.1% in the artemether group, and increased by 50.8% in the placebo group. No acute cases of schistosomiasis japonica were observed in the artemether group, whereas three such cases were reported from the placebo group. Compliance with regard to multi-doses of artemether and placebo was 84.9, and 77.9%, respectively. This study confirms that repeated oral artemether produces no drug-related adverse effects, significantly reduces incidence and intensity of patent S. japonicum infection and results in high compliance. Hence it can be used as an additional tool for the control of schistosomiasis japonica in the lake regions of China.

Schistosomiasis

Schistosomiasis is a disease that is relatively rare in the United States but has become an endemic in more than 74 countries. This disease has infected some 200 million people worldwide, particularly in developing countries. The disease is caused by parasitic worms, or flukes, which reside in contaminated or poorly sanitized fresh water. The most common effects of the disease are urinary tract and abdominal/intestinal disorders. Sonography has become an invaluable tool in detecting the clinical presentation of schistosomiasis, although lab studies of fecal and urine contents are the required to confirm infection. Although there is no current vaccine available for schistosomiasis, advances in drugs such as praziquantel, oxamniquine, and metrifonate have led to highly effective treatment. These drugs have led to a substantial reduction in morbidity in many areas. Mortality rates have also declined, but when present, it is usually due to intestinal bleeding or bladder cancer.

Effects of praziquantel and artesunate on the tegument of adult Schistosoma mekongi harboured in mice

The effects of praziquantel and artesunate on the tegument of adult Schistosoma mekongi harboured in mice were compared using scanning electron microscopy (SEM). Forty-two mice infected with S. mekongi for 49 days were treated intragastrically with either 300 mg/kg praziquantel or 300 mg/kg artesunate. Mice were sacrificed 1 or 3 days post-treatment. Worms were collected by perfusion and examined by SEM. One to 3 days after administration of artesunate, the tegument of S. mekongi showed severe swelling, vacuolization, fusion of the tegumental ridges and loss or shortening of the spines on the trabeculae, collapse and peeling. Praziquantel induced similar tegumental alterations as those observed after administration of artesunate, but they were less severe. Three days post-treatment, there was evidence of recovery only in the case of praziquantel. The results of our study suggest that artesunate is more effective than praziquantel in causing tegumental damage in adult S. mekongi, and provides a basis for subsequent clinical trials.

A novel nonsteroidal antifibrotic oligo decoy containing the TGF-beta element found in the COL1A1 gene which regulates murine schistosomiasis liver fibrosis

Schistosomiasis mansoni disseminated worm eggs in mice and humans induce granulomatous inflammations and cumulative fibrosis causing morbidity and possibly mortality. In this study, intrahepatic and I.V. injections of a double-stranded oligodeoxynucleotide decoy containing the TGF-beta regulatory element found in the distal promoter of the COL1A1 gene into worm-infected mice suppressed TGF-beta1, COL1A1, tissue inhibitor of metalloproteinase-1, and decreased COL3A1 mRNAs to a lesser extent. Sequence comparisons within the mouse genome found homologous sequences within the COL3A1, TGF-beta1, and TIMP-1 5' flanking regions. Cold competition gel mobility shift assays using these homologous sequences with 5' and 3' flanking regions found in the natural COL1A1 gene showed competition. Competitive gel mobility assays in a separate experiment showed no competition using a 5-base mutated or scrambled sequence. Explanted liver granulomas from saline-injected mice incorporated 10.45 +/- 1.7% (3)H-proline into newly synthesized collagen, whereas decoy-treated mice showed no collagen synthesis. Compared with the saline control schistosomiasis mice phosphorothioate double-stranded oligodeoxynucleotide treatment decreased total liver collagen content (i.e. hydroxy-4-proline) by 34%. This novel molecular approach has the potential to be employed as a novel antifibrotic treatment modality.

Prospects for development of a transmission blocking vaccine against Schistosoma japonicum

Despite intensive long-term control programmes, schistosomiasis japonica remains a serious public health problem in China and the Philippines. The termination of mass praziquantel-treatment has seen a dramatic recent rebound in both its prevalence and associated morbidity. Schistosomiasis japonica is a zoonosis but, despite complicating control efforts, this feature provides a practical method for attacking Schistosoma japonicum through development and deployment of a transmission blocking veterinary vaccine. A recently completed bovine drug intervention trial and mathematical modelling of the transmission of S. japonicum underpin the concept that such a vaccine, targeting water buffalo, would have major implications for future integrated schistosomiasis control in China. A major block to success is the low ceiling efficacy achieved with current vaccine molecules. To solve this challenge, an antigen discovery pipeline needs to be established for identification of new vaccine targets that induce greater potency than the current anti-S. japonicum candidate vaccines. Excretory-secretory products and molecules exposed on epithelial surfaces (including receptors) which interact directly with the host immune system warrant especial attention. Extensive schistosome genomics programmes currently underway coupled with new advances in proteomics and microarray technology provide an unparalleled opportunity to identify new molecules exploitable as vaccine targets. These will then need to be produced in quantity and rigorously tested first in the laboratory and then the field. If a transmission blocking veterinary vaccine developed for bovines can be put into practice in combination with other control strategies such as human chemotherapy, elimination of S. japonicum from China may be achievable.

The cellular distribution and stage-specific expression of two dynein light chains from the human blood fluke Schistosoma japonicum

Schistosomes are pathogenic helminth parasites of human portal veins. Their body wall is a highly active syncytial tegument involved in an array of host interactions. The cytoskeletal organization and dynamics of this syncytium are poorly understood, but predominant motor components are the LC8 class of cytoplasmic dynein light chains (DLC). Four LC8 members occur in schistosomes, two of which are expressed in the tegument. Here, we describe the cytoplasmic distribution, stage-specific expression and cellular location of two diverse LC8 molecules of Schistosoma japonicum. SjDLC1 was detected in surface-membrane specific extracts of adult worms and was shown by quantitative immuno-electron microscopy to predominate along heptalaminate membranes of the worm surface. SjDLC3 also occurs in the tegument, but was shown to be present in basal layers of the tegument and did not preferentially co-localize with particular membrane components. SjDLC3 was also detected in the gastrodermis. SjDLC1 is expressed only in mammalian-parasitic stages, whereas SjDLC3 is expressed throughout the life-cycle. The data suggest that SjDLC1 is preferentially located to the host-interactive distal parasite membrane, and plays a role in surface membrane dynamics, while SjDLC3 is a ubiquitous motor component of schistosome epithelia of all stages.

Schistosomiasis in einem uterinen Leiomyom

This case report deals with an, in our regions, unusual diagnosis of coincidence of a genital schistosomiasis of a 30-year-old woman, coming from Africa. The female patient presented herself by a specialist because of longer lasting hypermenorrhoe. After clinical examination the patient underwent an operation because of an uterus myomatosus. The histopathological evaluation showed beside a leimyoma an expanded infestation with schistosomiasis haematobium. After pathological diagnosis the patient underwent the standard therapy with a single injection of praziquantel. We report about the clinic, epidemiology, morphology and diagnostic.

Schistosomiasis mansoni -- clinical features

In the present review, we will discuss the Schistosoma mansoni form, which is the most widely distributed schistosome in humans and is found both in the Old and New Worlds. The main features of the natural history of mansonic schistosomiasis are reviewed, with emphasis on the clinical forms of the disease, their diagnosis and treatment.

The Schistosoma mansoni Src kinase TK3 is expressed in the gonads and likely involved in cytoskeletal organization

Cytoplasmic protein tyrosine kinases of the Src family play a pivotal role in the regulation of cellular processes including proliferation and differentiation. Among other functions, Src kinases are involved in regulating the cell architecture. In an approach to identify protein tyrosine kinases from the medically important parasite Schistosoma mansoni, we isolated the TK3 gene by degenerate primer PCR and cDNA library screening. Sequencing of the complete cDNA and data-base analyses indicated that TK3 is a Src family kinase. Its predicted size of 71 kDa was confirmed by Western blot analysis. Southern blot analysis showed that TK3 is a single-copy gene, and Northern blot and RT-PCR experiments indicated its expression in both sexes and throughout development. Localization studies by in situ hybridization and immunolocalization revealed that TK3 is predominantly expressed in the reproductive organs such as the testes of the male and the ovary as well as the vitellarium of the female. Its enzymatic activity was confirmed by functional analyses. In transient transfection experiments with HEK293 cells, TK3 phosphorylated the well-known Src-kinase substrate p130 Cas, an intracellular scaffolding protein. Yeast two-hybrid screenings in a heterologous invertebrate system identified dAbi, vinculin and tubulin as binding partners, representing molecules that fulfill functions in the cell architecture of many organisms. These findings suggest that TK3 may play a role in signal transduction pathways organizing the cytoskeleton in the gonads of schistosomes.

Retroviral Foxp3 gene transfer ameliorates liver granuloma pathology in Schistosoma mansoni infected mice

Schistosomiasis mansoni, a tropical helminthic disease, is caused by disseminated worm eggs that induce CD4(+) T-cell mediated granulomatous inflammation and fibrosis. T suppressor cell activity has been proposed as one of the mechanisms active in the down-modulation of the murine disease during the chronic stage (16-20 weeks of the infection). In recent years a new category of the CD4(+) CD25(+) T regulatory (Treg) lymphocyte has been identified that maintains immune tolerance to self, and also functions in the regulation of parasite-induced immunopathology. The Foxp3 gene which encodes the transcription factor Scurfin was found to be expressed by and required for the generation of CD4(+) CD25(+) T reg. At 8 weeks of the infection Foxp3 gene expression of splenocytes was similar to that of naive mice, but increased fourfold by 16 weeks. In contrast, granulomatous livers at 8 and 16 weeks showed 10- and 30-fold increases, respectively, in gene expression compared with normal liver. The percentage of granuloma CD4(+) CD25(+) T cells rose from 12% at 8 weeks to 88% at 16 weeks of the infection. Foxp3 expression was 3.5-fold higher in the CD4(+) CD25(+) versus the CD4(+) CD25(-) T cells in the 8 week infection granulomas. As a novel observation neuropilin-1 membrane expression, a recently identified marker for Treg, was correlated with Foxp3 expression in the granuloma CD4(+) CD25(+) but not the CD25(-) cells. Co-incubation with polyclonal stimulation of CD4(+) CD25(+) splenic cells with CD4(+) CD25(-) cells suppressed proliferation of the latter. Retroviral transfer of the Foxp3 gene at the onset of granuloma formation enhanced fourfold Foxp3 expression in the granuloma CD4(+) CD25(+) T cells and strongly suppressed full granuloma development. Gene transfer also significantly enhanced transforming growth factor-beta, interferon-gamma and interleukin-4 but not interleukin-10 expression. It is concluded, that CD4(+) CD25(+), Foxp3(+) Treg cells also regulate schistosome egg-induced immunopathology.

Granulomatous diseases of the central nervous system

Infectious diseases of the central nervous system (CNS), particularly those accompanied by the formation of granulomas, are a constant diagnostic challenge in some specific regions of the world, above all in developing countries. The pattern of image seen on CT or MR scan is the result of the inter-relations between the individual characteristics of the infectious agent and the capacity of each host to mount an appropriate inflammatory response to that specific type of aggression, inside one particular compartment of the CNS. Taking these parameters into account we will discuss the several patterns of image found in parasitic, bacterial, and fungal granulomatous infections.

Helminthic Infections of the Liver

Human helminthic infestation is exceedingly common on a global scale, with as many as 1.5 to 2 billion people affected worldwide. Helminths (parasitic worms) that infect the liver and hepatobiliary system include nematodes (roundworms), cestodes (tapeworms), and trematodes (flatworms or flukes). The majority of morbidity and mortality from these infestations is caused by the host immune response to the larvae or adult worm. Helminthic disease manifestations vary from the extremes of asymptomatic carriage to cirrhosis and decompensated liver disease. Current basic science and clinical research focus on improvements in medical therapy, mass screening and chemoprophylaxis, and the development of preventative vaccine strategies.

Expression, purification, and human antibody response to a 67 kDa vaccine candidate for schistosomiasis japonica

Schistosomiasis remains a leading cause of morbidity and mortality in the developing tropical world, and vaccines to prevent these infections remain a scientific and public health priority. Sj67 is a 67 kDa Schistosoma japonicum surface membrane protein homologous to a family of actin-binding proteins. Sj67 is recognized by a mouse monoclonal antibody (mAb 6) that confers resistance to challenge infection in passive transfer experiments. These data support Sj67 as a potential vaccine candidate for schistosomiasis japonica. In the present study, we report the ligation-independent cloning of a cDNA encoding thioredoxin/elastin-like polypeptide (ELP)/rSj67 into a pET-32 Xa/LIC vector. Soluble recombinant fusion protein (Thio-ELP-rSj67) was expressed and purified using anion-exchange and size exclusion chromatography. rSj67 was cleaved from the Thio-ELP fusion partner by digestion with Factor Xa protease and purified using hydroxyapatite column chromatography. Endotoxin was reduced by absorption to a polymyxin support. Purified rSj67 had a molecular weight of 67 kDa and N-terminal sequencing confirmed that the first five amino acids of the recombinant protein matched the predicted sequence for the Sj67 gene. In Western blot analysis, rSj67 was recognized by the Sj67 specific mAb 6 antibody. IgG antibodies in sera from schistosomiasis infected volunteers living in an endemic area of the Philippines (n = 13) recognized rSj67 with 4.7-fold greater median fluorescence compared to uninfected North American controls (n = 5) (p < 0.009). Together, these data confirm the expression and purification of recombinant Sj67 and its immuno-reactivity with sera from S. japonicum infected humans.

Mapping fucosylated epitopes on glycoproteins and glycolipids ofSchistosoma mansonicercariae, adult worms and eggs

The developmental expression of the antigenic fucosylated glycan motifs Fucα1-3GalNAcβ1-4GlcNAc (F-LDN), Fucα1-3GalNAcβ1-4(Fucα1-3)GlcNAc (F-LDN-F), GalNAcβ1-4(Fucα1-3)GlcNAc (LDN-F), Galβ1-4(Fucα1-3)GlcNAc (Lewis X), and GalNAcβ1-4(Fucα1-2Fucα1-3)GlcNAc (LDN-DF) inSchistosoma mansonicercariae, adult worms and eggs, was surveyed using previously defined anti-carbohydrate monoclonal antibodies (mAbs). Lewis X was found both on glycolipids and glycoproteins, yet with completely different expression patterns during the life-cycle: on glycolipids, Lewis X was mainly found in the cercarial stage, while protein-conjugated Lewis X was mainly present in the egg stage. Also protein-conjugated LDN-F and LDN-DF were most highly expressed in the egg-stage. On glycolipids LDN-DF was found in all three examined stages, whereas LDN-F containing glycolipids were restricted to adult worms and eggs. The motifs F-LDN and F-LDN-F were found both on glycoproteins and glycolipids of the cercarial and egg stage, while in the adult stage, they appeared to occur predominantly on glycolipids. Immunofluorescence assays (IFA) showed that these F-LDN and F-LDN-F containing glycolipids were localized in a yet undefined duct or excretory system of adult worms. Murine infection serum showed major reactivity with this adult worm duct-system, which could be fully inhibited by pre-incubation with keyhole limpet haemocyanin (KLH). Clearly, the use of defined mAbs provides a quick and convenient way to map expression profiles of carbohydrate epitopes.

Helminthic infections of the liver

Human helminthic infestation is exceedingly common on a global scale, with as many as 1.5 to 2 billion people affected worldwide. Helminths (parasitic worms) that infect the liver and hepatobiliary system include nematodes (roundworms), cestodes (tapeworms), and trematodes (flatworms or flukes). The majority of morbidity and mortality from these infestations is caused by the host immune response to the larvae or adult worm. Helminthic disease manifestations vary from the extremes of asymptomatic carriage to cirrhosis and decompensated liver disease. Current basic science and clinical research focus on improvements in medical therapy, mass screening and chemoprophylaxis, and the development of preventative vaccine strategies.

Hematologic problems in immigrants from Southeast Asia

An increasing number of Southeast Asian immigrants have come to North America. Physicians who care for this population should be aware of the high prevalence of hematologic disorders and develop an approach to their diagnosis and management. Malaria and the hematologic sequelae, glucose-6-phophate dehydrogenase deficiency, the thalassemia syndromes, Southeast Asian ovalocytosis, visceral leishmaniasis, HIV infection, and iron-deficiency anemia, all of which may pertain to these patients, are reviewed in this article.

Schistosomiasis--an unusual cause of ureteral obstruction: a case history and perspective

A male, 32 years of age, presented with dysuria and abdominal pain, but no gross hematuria. He emigrated three years earlier from Somalia, East Africa, and was currently employed as a poultry processor in a rural Wisconsin community. The patient denied any trauma, sexual activity, or family history of significant illness. Abdominal and genitourinary exams were normal with negative tests for gonococcus and chlamydia. Urinalysis demonstrated microhematuria. A urogram and retrograde pyelogram revealed a mildly dilated right ureter down to the ureterovesical junction. Cystoscopy showed punctate white lesions on the bladder urothelium. Ureteroscopy was used to biopsy abnormal tissue in the distal ureter and bladder. Biopsy tissue demonstrated deposits of Schistosoma haematobium eggs. No ova were seen in collected urine specimens. The patient was successfully treated with praziquantel and will be monitored for sequelae of the disease. Schistosomiasis (Bilharziasis) can be expected to be seen with increasing frequency in the United States with the continuing influx of immigrants and refugees, as well as the return of travelers and soldiers from endemic areas. While no intermediate snail host exists for the transmission of Schistosoma sp. in the United States, the continued importation of exotic animals including snails from Africa, as well as the ability of schistosomes to shift host species warrants concern. Additionally, increasing disease associated with non-human bird schistosomes of the same genus seen in the midwestern United States is occurring throughout Europe. One should be aware that praziquantel may not always be available or effective in the treatment of schistosomiasis. It behooves the practicing clinician to remain updated on the status of this widespread zoonosis.

Childhood stunting in Northeast Brazil: the role of Schistosoma mansoni infection and inadequate dietary intake

OBJECTIVE

To evaluate the relationship between stunting, Schistosoma mansoni infection and dietary intake in schoolchildren.

DESIGN

This is a cross-sectional study. Two stool samples were obtained from each child and examined quantitatively for the presence of S. mansoni, Ascaris lumbricoides and Trichuris trichiuria eggs. Information on dietary intake, and demographic, biologic and socioeconomic variables was elicited during the in-home survey. Logistic regression was used to evaluate the association between stunting (height for age < -2s.d.), parasitic infection and food consumption.

SETTING

The study was carried out in the city of Nazaré, located in the Recôncavo region of the State of Bahia, Northeastern Brazil.

SUBJECTS

The sample consisted of 461 children 7-14 y old, 228 boys and 233 girls, recruited from public schools.

RESULTS

Of the children studied, 55.1% presented with S. mansoni infection and 22.1% were stunted. The median protein, lipid and carbohydrates intake were 47.8, 36.0 and 248.2 g/day, respectively. The median caloric consumption was 1527.0 kcal (6388.97 kJ/day). The analysis indicated that children heavily infected (> or = 400 eggs/g of stool) with S. mansoni had a 2.74-fold (95% CI: 1.32-5.67) higher risk of stunting than uninfected children, and those with inadequate intake of lipid (< 36 g/day) had a 1.83-fold (95% CI: 1.05-3.20) increased risk of stunting compared to those with adequate diets.

CONCLUSION

Heavy S. mansoni infection and inadequate dietary intake of fat in schoolchildren play a significant and independent role in the development of stunting. This meaning that nutritional interventions in this age group in S. mansoni endemic areas must include the diagnosis and treatment of the infection associated with dietary measures.

SPONSORSHIP

This study was supported by the Thrasher Foundation. Sandra Maria Conceição Pinheiro is a National Council on Technological Development Scholarship Awardee (CNPq), #302228/81-0.

Avaliação hepática e esplênica por ressonância magnética em pacientes portadores de esquistossomose mansônica crônica

OBJETIVO: Avaliar, qualitativa e quantitativamente, as alterações morfológicas hepáticas e esplênicas por ressonância magnética (RM) em pacientes portadores de esquistossomose mansônica crônica, e a reprodutibilidade do método na avaliação hepatoesplênica destes pacientes. MATERIAIS E MÉTODOS: Realizou-se estudo prospectivo em 28 pacientes esquistossomóticos submetidos à RM de abdome superior. Os exames foram realizados em equipamento com alto campo (1,5 T), utilizando-se bobina de corpo e bomba injetora para a administração do contraste endovenoso, e interpretados por dois examinadores independentes, que avaliaram a presença de alterações morfológicas hepáticas e esplênicas. A concordância interobservador e intra-observador foram medidas pelo teste kappa e pelo teste do coeficiente de correlação intraclasses. RESULTADOS: As variáveis qualitativas e quantitativas apresentaram boa concordância interobservador e intra-observador (kapa > 0,65 e r > 0,66, respectivamente). A maior concordância interobservador foi obtida para o diâmetro ântero-posterior do baço (r = 0,98). Os observadores identificaram redução do lobo hepático direito, aumento do lobo hepático esquerdo e caudado associado a esplenomegalia em quase todos os pacientes, e alargamento de fissuras, heterogeneidade do parênquima hepático, irregularidade de contornos, vasos periféricos hepáticos e fibrose periportal em mais de 82% dos pacientes. CONCLUSÃO: As alterações morfológicas hepáticas caracterizam-se pela redução do lobo direito e aumento dos lobos caudado e esquerdo, e as esplênicas, pela presença de esplenomegalia e nódulos sideróticos. A RM apresenta elevada reprodutibilidade na avaliação dessas alterações em pacientes com esquistossomose mansônica crônica.

Ultrasound organometry: the importance of body height adjusted normal ranges in assessing liver and spleen parameters among Chinese subjects with Schistosoma japonicum infection

Hepatosplenic measurements among 550 Chinese subjects, aged 3-59 years from Yueyang city--a nonendemic area for schistosomiasis in Hunan province, China--were performed to define normal ranges of ultrasound organometry for assessing hepatosplenic morbidity in Schistosoma japonicum infection. Measurements included the size of the liver (left lobe and right lobe), the main portal vein stem, the peripheral periportal vein branches, and spleen length and thickness. The results document the significant relationship between body height and organometric parameters. The reference values stratified by body height improve the accuracy of assessment. Thus, height-based normal ranges established in this study can be applied in hospital routine and in field studies of patients infected with S. japonicum in Hunan province and in other endemic areas of China.

Schistosome transcriptome analysis at the cutting edge

We live in the era of post-genomics, a term that was, until recently, inappropriate when considering the blood flukes of humans because of the relative lack of knowledge of the schistosome genome. The position has, however, changed dramatically following the recent publication of two landmark papers on transcriptome analysis of Schistosoma japonicum and Schistosoma mansoni. In a quantum leap, both studies report on the identification of many novel genes and genes not previously known from schistosomes. The datasets provide new insights into the biology of the schistosomes and offer an opportunity for identification of potential antischistosome vaccine candidates and drug targets. Remarkable recent progress has also been achieved in genomic sequencing, and completed genomes for both species can be expected shortly.