Schistosomiasis

Serological diagnosis of echinococcosis: the diagnostic potential of native antigens

PURPOSE

Human alveolar (AE) and cystic echinococcosis (CE) caused by the metacestode stages of Echinococcus multilocularis and E. granulosus, respectively, lack pathognomonic clinical signs. Diagnosis therefore relies on the results of imaging and serological studies. The primary goal of this study was to evaluate the efficacy of several easy-to-produce crude or partially purified E. granulosus and E. multilocularis metacestode-derived antigens as tools for the serological diagnosis and differential diagnosis of patients suspicious for AE or CE.

METHODS

The sera of 51 treatment-naïve AE and 32 CE patients, 98 Swiss blood donors and 38 patients who were initially suspicious for echinococcosis but suffering from various other liver diseases (e.g., liver neoplasia, etc.) were analysed.

RESULTS

According to the results of enzyme-linked immunosorbent assays (ELISA), metacestode-derived antigens of E. granulosus had sensitivities varying from 81 to 97% and >99.9% for the diagnosis of CE and AE, respectively. Antigens derived from E. multilocularis metacestodes had sensitivities ranging from 84 to 91% and >99.9% for the diagnosis of CE and AE, respectively. Specificities ranged from 92 to >99.9%. Post-test probabilities for the differential diagnosis of AE from liver neoplasias, CE from cystic liver lesions, and screening for AE in Switzerland were around 95, 86 and 2.2%, respectively. Cross-reactions with antibodies in sera of patients with other parasitic affections (fasciolosis, schistosomosis, amebosis, cysticercosis, and filarioses) did occur at variable frequencies, but could be eliminated through the use of confirmatory testing.

CONCLUSIONS

Different metacestode-derived antigens of E. granulosus and E. multilocularis are valuable, widely accessible, and cost-efficient tools for the serological diagnosis of echinococcosis. However, confirmatory testing is necessary, due to the lack of species specificity and the occurrence of cross-reactions to other helminthic diseases.

Schistosoma mansoni infection in the liver graft: The impact on donor and recipient outcomes after transplantation

The increasing number of transplants performed each year has led to the identification of unusual diseases in liver grafts from asymptomatic donors that were unrecognized before liver transplantation. Here we report our experience with patients who received liver grafts infected with schistosomiasis. From September 1991 to August 2010, 482 pediatric liver transplants were performed at A. C. Camargo Hospital/Sírio-Libanês Hospital (São Paulo, Brazil). For the identification of Schistosoma mansoni infections, pathology slides for the recipients were reviewed; these included postreperfusion and follow-up liver biopsy samples. We were able to identify 6 cases of schistosomiasis transmitted through infected grafts (5 of these grafts were from living donors). All living donors were confirmed to have normal liver chemistries, negative fecal tests for parasitic diseases, and normal abdominal ultrasound findings. Liver biopsy was not performed before transplantation. In all cases, features of schistosomiasis were absent in the liver explants. The living donors were treated with praziquantel and were taught to avoid risk factors for reinfection. No specific treatment for schistosomiasis was given to the recipients. There were no perioperative deaths, but 2 recipients died after living donor liver transplantation (LDLT) because of Kaposi's sarcoma and non-Hodgkin's lymphoma. In conclusion, using liver grafts infected with S. mansoni eggs did not compromise the results of LDLT in this pediatric cohort. Because of the parasite's life cycle and the therapeutic target of praziquantel, only donors should be treated for the infection. Three years of follow-up showed an uneventful recovery for the living donors.

Efficacy of praziquantel and artemisinin derivatives for the treatment and prevention of human schistosomiasis: a systematic review and meta-analysis

Background

Praziquantel has been used as first-line drug for chemotherapy of schistosomiasis since 1984. Besides praziquantel, artemether and artesunate have also been used for the control of this infectious disease since late 1990s. In this article, we conducted a systematic review and meta-analysis to evaluate the antischistosomal efficacy of different medication strategies including monotherapy or combination therapies of these drugs.

Results

A number of 52 trials from 38 articles published in peer-reviewed journals before July 2011 were selected for analysis after searching the following literature databases: the Cochrane Library, PubMed/Medline, ISI Web of Science, Chinese Biomedicine Literature Database, and China National Knowledge Infrastructure. Our meta-analyses showed that a dosage of 30-60 mg/kg praziquantel compared with placebo produced a protection rate of about 76% (95% CI: 67%-83%) for treating human schistosomiasis, which varied from 70% to 76% with no significant differences among the subspecies S. haematobium, S. japonicum or S. mansoni. Protection rates were higher when praziquantel doses were elevated, as concluded from the nRCTs results: the protection rate of praziquantel at 40 mg/kg was 52% (95% CI: 49%-55%), and it increased to 91% (95% CI: 88%-92%) when the dosages were elevated to 60/80/100 mg/kg divided two or more doses. Multiple doses of artemether or artesunate over 1- or 2-week intervals resulted in protection rates of 65% to 97% for preventing schistosomiasis, and increased doses and shorter medication intervals improved their efficacies. Praziquantel and artemisinin derivatives (artemether or artesunate) in combination resulted in a higher protection rate of 84% (95% CI: 64%-91%) than praziquantel monotherapy for treatment. praziquantel and artesunate in combination had a great protection rate of 96% (95% CI: 78%-99%) for preventing schistosomes infection.

Conclusions

According to the results, praziquantel remains effective in schistosomiasis treatment, and multiple doses would improve its efficacy; meanwhile, praziquantel is also a good drug for preventing acute schistosomiasis morbidity. It's better to use multiple doses of artemether or artesunate with 1- or 2-week intervals for prevention against schistosome infection. Praziquantel and artemether or artesunate in combination perform better in treatment than praziquantel monotherapy, and they are especially suitable for treating the patients with repeated exposure to infected water.

[Nonbacterial colitides]

Aside from bacterial infections, viral, fungal, and parasitic infections are important differential diagnoses in inflammatory disorders of the colorectum. In contrast to bacterial infections, in which the causative organism can hardly ever be detected histologically, in non bacterial infections the germs can often be verified by either histology, immunohistochemistry, or at least by molecular pathology. This manuscript will give an overview of the spectrum of pathogenic germs, the clinical symptoms, and pathological findings of the most important infections.

Resolution of praziquantel

Background

Praziquantel remains the drug of choice for the worldwide treatment and control of schistosomiasis. The drug is synthesized and administered as a racemate. Use of the pure active enantiomer would be desirable since the inactive enantiomer is associated with side effects and is responsible for the extremely bitter taste of the pill.

Methodology/Principal Findings

We have identified two resolution approaches toward the production of praziquantel as a single enantiomer. One approach starts with commercially available praziquantel and involves a hydrolysis to an intermediate amine, which is resolved with a derivative of tartaric acid. This method was discovered through an open collaboration on the internet. The second method, identified by a contract research organisation, employs a different intermediate that may be resolved with tartaric acid itself.

Conclusions/Significance

Both resolution procedures identified show promise for the large-scale, economically viable production of praziquantel as a single enantiomer for a low price. Additionally, they may be employed by laboratories for the production of smaller amounts of enantiopure drug for research purposes that should be useful in, for example, elucidation of the drug's mechanism of action.

The drug praziquantel (PZQ) is used very widely in both animal and human medicine, where it is the mainstay of the treatment of the neglected tropical disease schistosomiasis. The drug is currently manufactured and administered as a racemate (1∶1 mixture of enantiomers) but for various reasons the large-scale production of PZQ as the single active enantiomer is very desirable. We describe here the preparation of praziquantel as a single enantiomer using classical resolution. The protocols are experimentally simple and inexpensive. One method was found and validated by an unusual research mechanism—open science—where the details of the collaboration (involving academic and industrial partners) and all research data were available on the web as they were acquired, and anyone could participate. The other route was found in parallel by a contract research organisation. Besides being possible routes by which praziquantel may be produced in large quantities for the affected communities, it is also hoped that these methods can be used for the production of smaller quantities of enantiopure PZQ for pharmacological studies.

Cercarial transformation and in vitro cultivation of Schistosoma mansoni schistosomules

Schistosome parasites are the causative agents of schistosomiasis, a chronically debilitating disease that affects over 200 million people globally and ranks second to malaria among parasitic diseases in terms of public health and socio-economic impact (1-4). Schistosome parasites are trematode worms with a complex life cycle interchanging between a parasitic life in molluscan and mammalian hosts with intervening free-swimming stages. Briefly, free-swimming cercariae infect a mammalian host by penetrating the skin with the aid of secreted proteases, during which time the cercariae lose their tails, transforming into schistosomules. The schistosomules must now evade the host immune system, develop a gut for digestion of red blood cells, and migrate though the lungs and portal circulation en route to their final destination in the hepatic portal system and eventually the mesenteric veins (for S. mansoni) where male and female worms pair and mate, producing hundreds of eggs daily. Some of the eggs are excreted from the body into fresh water, where the eggs hatch into free-swimming miracidia (5-10). The miracidia infect specific snail species and transform into mother and daughter sporocysts, which in turn, produce infective cercariae, completing the life cycle. Unfortunately, the entire schistosome life cycle cannot be cultured in vitro, but infective cercariae can be transformed into schistosomules, and the schistosomules can be cultured for weeks for the analysis of schistosome development in vitro or microarray analysis. In this protocol, we provide a visual description of cercarial transformation and in vitro culturing of schistosomules. We shed infectious cercariae from the snail host Biomphalaria glabrata and manually transform them into schistosomules by detaching their tails using an emulsifying double-ended needle. The in vitro cercarial transformation and schistosomules culture techniques described avoid the use of a mammalian host, which simplifies visualization of schistosomes and facilitates the collection of the parasite for experimental analysis. in vitro transformation and culturing techniques of schistosomes have been done for years (11, 12), but no visual protocols have been developed that are available to the entire community.

Praziquantel reverses pulmonary hypertension and vascular remodeling in murine schistosomiasis

RATIONALE

Schistosomiasis is the most common worldwide cause of pulmonary arterial hypertension. The anti-schistosome drug praziquantel has been shown to reverse the liver fibrosis associated with Schistosoma mansoni in mice.

OBJECTIVES

We sought to determine whether praziquantel reverses established pulmonary vascular remodeling and pulmonary hypertension in a mouse model of S. mansoni.

METHODS

Mice were infected percutaneously with S. mansoni. At 17 weeks after infection mice were either killed or received two doses of praziquantel or vehicle by oral gavage. Treated mice were studied at 25 weeks after infection.

MEASUREMENTS AND MAIN RESULTS

Vehicle-treated mice demonstrated significant increases in right ventricular systolic pressures (RVSP) and right ventricular hypertrophy (RVH) at 25 weeks, accompanied by pulmonary vascular remodeling. The degree of vascular remodeling correlated with proximity to granulomas. The elevation of RVSP and RVH at 25 weeks was dependent on the presence of eggs in the lung. Praziquantel eliminated the production of eggs in feces and led to clearance of eggs from the lung and to a lesser extent from liver. Praziquantel prevented the rise in RVSP and RVH seen in vehicle-treated mice and reversed established pulmonary vascular remodeling. Praziquantel significantly reduced lung mRNA expression of IL-13, IL-8, and IL-4, but did not reduce serum cytokine levels.

CONCLUSIONS

The development of pulmonary hypertension associated with S. mansoni infection can be prevented by praziquantel, and established vascular remodeling can be reversed. The mechanism involves clearance of lung eggs and reduced local expression of lung cytokines.

New insights into gastrointestinal and hepatic granulomatous disorders

Numerous diseases that involve the gastrointestinal tract reveal the presence of granulomas on histological analysis. Granulomatous diseases can be either primary or secondary to environmental factors. Granulomas are dynamic structures composed of organized collections of activated macrophages, including epithelioid and multinucleated giant cells, surrounded by lymphocytes. The formation of granulomas is usually in response to antigenic stimulation and is orchestrated through cytokines, immune cells and host genetics. In this Review, the pathogenesis and etiologies of granulomas of the gastrointestinal tract and liver are discussed, as are the available diagnostic tools to help differentiate their various underlying etiologies. In addition, the role of granulomas in harboring latent tuberculosis is reviewed. The effects of tumor necrosis factor antagonists and interferon-α on the development of granulomas are also discussed.

Paeoniflorin attenuates schistosomiasis japonica-associated liver fibrosis through inhibiting alternative activation of macrophages

Interleukin (IL)-13 and alternatively activated macrophages (AAMs) play an important role in liver granuloma and fibrosis of schistosomiasis. Paeoniflorin (PAE, C23H28O11) has been reported to have an anti-hepatic fibrosis effect in schistosomiasis; however, the mechanism has not been fully elucidated. In this study, we measured serum hyaluronic acid (HA) concentrations, liver granuloma diameter and volume density, fibrosis degree and expressions of IL-13, arginase-1 (ARG-1), nitric oxide synthase-2 (NOS-2), and phosphorylated signal transducer and activator of transcription 6 (p-STAT6) in mice liver of schistosomiasis. Then we detected expressions of specific biomarkers of AAMs and activity of Arg-1 in Kupffer cells (KCs) from infected and PAE-treated mice, or in KCs from uninfected mice, but exposed to rIL-13 in vitro. Finally, we observed expression of IL-13 signalling molecules in KCs and secretion of IL-13 from lymphocytes of infected and PAE-treated mice. Our results showed that during schistosomiasis, IL-13 expression and secretion increased with liver macrophages activated alternatively. PAE not only directly inhibited alternative activation of macrophages via reducing the phosphorylations of janus-activated kinase 2 (JAK2) and/or STAT6, leading to reduction of AAMs-related markers and Arg-1 activity, but also indirectly suppressed alternative activation of macrophages through decreasing secretion of IL-13. PAE might be a promising prophylactic agent for hepatic granuloma and fibrosis of schistosomiasis japonica.

Ultrasound in austere settings: a case report from a field hospital in Haiti

This case report from a field hospital in post-earthquake Haiti underscores the utility of portable ultrasound in austere environments. An 8-year-old boy was evaluated for several weeks of fevers and chills, general malaise, and increasing abdominal girth. He appeared ill with mild tachypnea, decreased breath sounds at bilateral lung bases, a distended abdomen with a palpable fluid wave, and bilateral pitting edema. This clinical picture was concerning for advanced schistosomiasis and ultrasound findings supported this presumptive diagnosis and helped direct treatment. Images from this case demonstrated several classic ultrasound findings described by the WHO including hepatosplenomegaly and diffuse fibrotic changes in the hepatobiliary and urogenital tracts. This case report demonstrates the effective use of portable ultrasound in making an accurate diagnosis and forming a definitive treatment plan for a patient in a resource-limited environment.

Effects of protein extract from head-foot tissue of Oncomelania hupensis on the growth and gene expression of mother sporocysts of Schistosoma japonicum

Oncomelania hupensis is the intermediate host of Schistosoma japonicum. In the present study, we investigated the effects of protein extracts from head-foot or gland tissue of O. hupensis on mother sporocysts of S. japonicum cultured in vitro. In the presence of head-foot protein extract of snails from the native province Hunan, in-vitro-transformed mother sporocysts presented not only a longer survival time and stronger motility, but also a bigger size than parasites cultured with protein extracts of glands of the same snail or head-foot tissue of a non-native snail from the Hubei province. Using suppression subtractive hybridization, two subtractive libraries were constructed on the basis of RNA of sporocysts cultured with or without native snail head-foot protein extract. A number of 31 transcripts were found to be up-regulated. Sequence analyses revealed that they represented genes involved among others in metabolic process, electron transport chain, response to chemical stimulus, and oxidation-reduction processes. Opposite to that 20 down-regulated transcripts were among others related to pseudouridine synthesis, RNA processing, and ribosome biogenesis. The differential expression of three of these transcripts, encoding cytochrome c oxidase subunit 2 (Cox2), NADH-ubiquinone oxidoreductase (ND1), and dyskeratosis congenita 1 protein (DKC1), were confirmed by real-time PCR. The promoted development and the differential gene expression of cultured sporocysts under the influence of head-foot protein extract of native O. hupensis implied not only its ability to improve in vitro culture conditions for intramolluscan stages, it may also represent a priming result with respect to the identification and characterization of factors involved in the parasite-host interplay between S. japonicum and O. hupensis.

False positive circumsporozoite protein ELISA: a challenge for the estimation of the entomological inoculation rate of malaria and for vector incrimination

Background

The entomological inoculation rate (EIR) is an important indicator in estimating malaria transmission and the impact of vector control. To assess the EIR, the enzyme-linked immunosorbent assay (ELISA) to detect the circumsporozoite protein (CSP) is increasingly used. However, several studies have reported false positive results in this ELISA. The false positive results could lead to an overestimation of the EIR. The aim of present study was to estimate the level of false positivity among different anopheline species in Cambodia and Vietnam and to check for the presence of other parasites that might interact with the anti-CSP monoclonal antibodies.

Methods

Mosquitoes collected in Cambodia and Vietnam were identified and tested for the presence of sporozoites in head and thorax by using CSP-ELISA. ELISA positive samples were confirmed by a Plasmodium specific PCR. False positive mosquitoes were checked by PCR for the presence of parasites belonging to the Haemosporidia, Trypanosomatidae, Piroplasmida, and Haemogregarines. The heat-stability and the presence of the cross-reacting antigen in the abdomen of the mosquitoes were also checked.

Results

Specimens (N = 16,160) of seven anopheline species were tested by CSP-ELISA for Plasmodium falciparum and Plasmodium vivax (Pv210 and Pv247). Two new vector species were identified for the region: Anopheles pampanai (P. vivax) and Anopheles barbirostris (Plasmodium malariae). In 88% (155/176) of the mosquitoes found positive with the P. falciparum CSP-ELISA, the presence of Plasmodium sporozoites could not be confirmed by PCR. This percentage was much lower (28% or 5/18) for P. vivax CSP-ELISAs. False positive CSP-ELISA results were associated with zoophilic mosquito species. None of the targeted parasites could be detected in these CSP-ELISA false positive mosquitoes. The ELISA reacting antigen of P. falciparum was heat-stable in CSP-ELISA true positive specimens, but not in the false positives. The heat-unstable cross-reacting antigen is mainly present in head and thorax and almost absent in the abdomens (4 out of 147) of the false positive specimens.

Conclusion

The CSP-ELISA can considerably overestimate the EIR, particularly for P. falciparum and for zoophilic species. The heat-unstable cross-reacting antigen in false positives remains unknown. Therefore it is highly recommended to confirm all positive CSP-ELISA results, either by re-analysing the heated ELISA lysate (100°C, 10 min), or by performing Plasmodium specific PCR followed if possible by sequencing of the amplicons for Plasmodium species determination.

Hepatic schistosomiasis

Praziquantel is the treatment of choice for schistosomiasis because of its efficacy, ease of administration, limited side effects, and low cost. Praziquantel has been so effective that alternative therapies are increasingly difficult to obtain, and the development of novel medications has been limited. The possibility of praziquantel resistance is a grave concern. Low cure rates for praziquantel have been reported in several countries, but despite widespread use, no significant loss of efficacy has occurred to date. The primary goal of antischistosomal therapy is parasite eradication, which reduces the likelihood of chronic complications, including advanced hepatic fibrosis. Mild to moderate hepatic fibrosis results from the immune response to schistosome eggs deposited in the portal venules and reverses with successful treatment. Most individuals clear schistosomiasis with a single course of therapy. Repeat doses cure the majority of patients in whom eradication does not occur after the initial dose. A secondary goal of therapy for patients with persistent or recurrent infection is egg burden reduction, which also reduces the risk of hepatic fibrosis and lowers community spread. Community eradication programs in highly endemic regions use periodic retreatment to limit chronic schistosomiasis' morbidity. Advanced liver fibrosis and portal hypertension due to chronic schistosomiasis are irreversible. Variceal bleeding is the primary cause of death in hepatic schistosomiasis. The bleeding risk is best reduced through use of beta-blocker prophylaxis or endoscopic banding or sclerotherapy. Surgical management of varices, including splenectomy with esophagogastric devascularization or selective shunts such as the distal splenorenal, is effective in patients with recalcitrant bleeding. Because hepatic synthetic function is normal in patients with schistosomiasis, procedures that reduce portal pressures may lower hepatic perfusion and cause hepatic impairment. The risk of encephalopathy after shunt surgery is higher in patients with schistosomiasis than in those with cirrhosis. For these reasons, nonselective shunt surgery such as the proximal splenorenal or the transjugular intrahepatic portosystemic shunt should not be performed in patients with advanced hepatic schistosomiasis.

Neuroschistosomiasis

Schistosomiasis (bilharzia) is a neglected tropical disease caused by digenetic trematode platyhelminths of the genus Schistosoma. Neuroschistosomiasis is one of the most severe clinical outcomes associated with schistosome infection. Neurological complications early during the course of infection are thought to occur through in situ egg deposition following aberrant migration of adult worms to the brain or spinal cord. The presence of eggs in the CNS induces a cell-mediated Th2-driven periovular granulomatous reaction. The mass effect of thousands of eggs and the large granulomas concentrated within the brain or spinal cord explain the signs and symptoms of increased intracranial pressure, myelopathy, radiculopathy and subsequent clinical sequelae. Myelopathy (acute transverse myelitis and subacute myeloradiculopathy) of the lumbosacral region is the most common neurological manifestation of S. mansoni or S. haematobium infection, whereas acute encephalitis of the cortex, subcortical white matter, basal ganglia or internal capsule is typical of S. japonicum infection. Cerebral complications include encephalopathy with headache, visual impairment, delirium, seizures, motor deficits and ataxia, whereas spinal symptoms include lumbar pain, lower limb radicular pain, muscle weakness, sensory loss and bladder dysfunction. The finding of eggs in the stool or a positive serology, provides supportive but not direct evidence of neuroschistosomiasis. A definitive diagnosis can only be made with histopathological study showing Schistosoma eggs and granulomas. Schistosomicidal drugs (notably praziquantel), steroids and surgery are currently used for the treatment of neuroschistosomiasis. During the 'acute phase' of the disease, neuroschistosomiasis is treated with corticosteroids which are augmented with a course of praziquantel once female worm ovipositioning commences. Surgery should be reserved for special cases such as in those with evidence of medullary compression and in those who deteriorate despite clinical management.

Association of HLA and post-schistosomal hepatic disorder: a systematic review and meta-analysis

Several human genetic variants, HLA antigens and alleles are reportedly linked to post-schistosomal hepatic disorder (PSHD), but the results from these reports are highly inconclusive. In order to estimate overall associations between human genetic variants, HLA antigens, HLA alleles and PSHD, we systematically reviewed and performed a meta-analysis of relevant studies in both post-schistosomal hepatic disorder and post-schistosomal non-hepatic disorder patients. PubMed, Scopus, Google Scholar, The HuGE Published Literature database, Cochrane Library, and manual search of reference lists of articles published before July 2009 were used to retrieve relevant studies. Two reviewers independently selected articles and extracted data on study characteristics and data regarding the association between genetic variants, HLA antigens, HLA alleles and PSHD in the form of 2×2 tables. A meta-analysis using fixed-effects or random-effects models to pooled odds ratios (OR) with corresponding 95% confidence intervals were calculated only if more than one study had investigated particular variation. We found 17 articles that met our eligibility criteria. Schistosoma mansoni and Schistosoma japonicum were reported as the species causing PSHD. Since human genetic variants were only investigated in one study, these markers were not assessed by meta-analysis. Thus, only HLA-genes (a total of 66 HLA markers) were conducted in the meta-analysis. Our meta-analysis showed that human leucocyte antigens HLA-DQB1*0201 (OR=2.64, P=0.018), DQB1*0303 (OR=1.93, P=0.008), and DRB1*0901 (OR=2.14, P=0.002) alleles and HLA-A1 (OR=5.10, P=0.001), A2 (OR=2.17, P=0.005), B5 (OR=4.63, P=0.001), B8 (OR=2.99, P=0.02), and B12 (OR=5.49, P=0.005) serotypes enhanced susceptibility to PSHD, whereas HLA-DQA1*0501 (OR=0.29, P≤0.001) and DQB1*0301 (OR=0.58, P=0.007) were protective factors against the disease. We further suggested that the DRB1*0901-DQB1*0201, DRB1*0901-DQB1*0303 and A1-B8 haplotypes enhanced susceptibility to PSHD, whereas DQA1*0501-DQB1*0301 linkage decreased the risk of PSHD. The result improved our understanding of the association between the HLA loci and PSHD with regard to pathogenic or protective T-cells and provided novel evidence that HLA alleles may influence disease severity.

Genital schistosomiasis in European women

Female genital schistosomiasis (FGS) is an isolated chronic form of schistosomiasis. Although most infections occur in residents of endemic areas, it has been clearly documented that brief freshwater exposure is sufficient to establish infection; thus, travellers may also be infected. The clinical manifestations of FGS are nonspecific, and lesions may mimic any neoplastic or infectious process in the female genital tract. It is important to take a careful history and physical examination, making sure to consider travel history in endemic areas. The diagnosis is confirmed by microscopy with egg identification or by serology. The standard of care for treatment is a single dose of oral praziquantel which avoids complications and substantial morbidity. Herein, we report a rare and original case of FGS in a European woman.

A role for peroxisome proliferator-activated receptors in the immunopathology of schistosomiasis?

Peroxisome proliferator-activated receptors (PPARs) have been demonstrated to have a role in immune regulation. In general, they are anti-inflammatory and promote Th2 type responses, and they are associated with the alternative activation of macrophages. Interestingly, helminth infections, such as the schistosome blood flukes that cause schistosomiasis, are characterised by a Th2 response and the accumulation of alternative activated macrophages. This would suggest that at some level, PPARs could have a role in the modulation of the immune response in schistosomiasis. This paper discusses possible areas where PPARs could have a role in this disease.

Total synthesis of the cyanolide A aglycon

The synthesis of the potent molluscicide cyanolide A has been achieved in 10 steps without the use of protecting groups. The synthesis features a key Sakurai macrocyclization/dimerization reaction that simultaneously forms both tetrahydropyran rings and the macrocycle of the natural product.

Characterization and expression of a novel cystatin gene from Schistosoma japonicum

Cystatins are a family of cysteine protease inhibitors that play a crucial role in the immune evasion from their host and in the adaptation to host defence. Here, we isolated a full-length cDNA sequence inferred to encode a novel cystatin gene from a blood fluke, Schistosoma japonicum. The cDNA, designated SjCystatin, comprised an open reading frame (ORF) of 306 bp, and encoded 101 amino acids with a predicted molecular weight of 11.3 kDa. This predicted protein shared a significant degree of sequence identity with the type I cystatin (stefin) of Schistosoma mansoni and Homo sapiens. These proteins exhibited a typical cystatin topology, including the absence of disulfide bonds and three conserved catalytic motifs, Gly at the N-terminus (Gly(6)), Gln-X-Val-X-Gly motif (Q(49)VVAG(53)) and an LP pair at the C-terminus (L(76)P(77)). The SjCystatin gene spanned 376 bp and contained three exons. The positions of two introns were conserved between the cystatin genes of trematodes and their vertebrate hosts. Reverse transcription polymerase chain reaction confirmed the transcription of SjCystatin in the egg, schistosomula and adult stages of S. japonicum. The encoding ORF region was cloned into pET-28a (+) prokaryotic expression vector. After purification, the recombinant protein SjCystatin (recSjCystatin), expressed in Escherichia coli, was used to immunize animals and produce its specific polyclonal antibody. Western blot analysis revealed that the native SjCystatin was expressed in the egg and adult stages. The enzyme activity assay of the recSjCystatin showed that it inhibited the proteolytic activity of papain. SjCystatin protein was mainly localized on the miracidium within eggs. Immunohistochemistry revealed that SjCystatin mainly localized in the epithelial cells lining the gut as well as the tegument on the surface of adult worms. The conserved genomic DNA structure among cystatin homologues of trematode and their vertebrate host emphasized the characteristics of compatibility between parasites and their hosts. This study provides the first insight into the gene and protein of S. japonicum cystatin and a basis for a further understanding the functions of this gene.

Pulmonary vascular disease associated with parasitic infection--the role of schistosomiasis

Parasitic diseases have been known to cause pulmonary vascular lesions. Schistosomiasis is the most common parasitic disease associated with pulmonary arterial hypertension, although other trematodes have been implicated. Systematic evaluation of and interest in this problem have been rekindled because of the current availability of pulmonary arterial hypertension treatment.

Pulmonary vascular disease associated with schistosomiasis

In this article we focus on the pathogenesis and clinical characteristics of schistosomiasis infection on the lung vasculature. Overall, the basic biology and understanding of Schistosoma immune responses and their effect on the cardiopulmonary system is limited in both animal and human models, which hinders clinical care and drug development. The inflammatory response to the eggs in the lung appears to contribute to the remodeling of the pulmonary vessels. Portal hypertension caused by parasitemia also appears to contribute to the development of pathophysiologic alterations of the pulmonary vascular bed. Antischistosomal therapy, praziquantel, used for pulmonary hypertension secondary to schistosomiasis usually has no effect, but it is given to prevent further progression of disease. Currently, there are no clinical trials for the treatment of pulmonary vascular disease secondary to schistosomiasis. Specialty drugs such as phosphodiesterase type 5 or tyrosine kinase inhibitors exhibit some interesting activity, yet are prohibitively expensive, lack safety and efficacy studies in schistosomiasis endemic populations, and tend to be limited by safety, efficacy, route of administration and compliance problems.

A rare case of hematuria

ABSTRACT The infestation by Schistosoma haematobium is common in African countries and West Asia. Its chronic phase is characterized by the deposition of eggs of the parasite in various tissues of the body causing inflammatory response, formation of granulomas and fibrosis. The disease often affects the urinary tract, presenting with hematuria and, in the terminal stage, renal failure by urinary obstruction and bladder squamous neoplasia. Since chronic infection can lead to significant morbidity, it is imperative that the physicians who serve this immigrant population become familiar with this disease. A case of an immigrant boy from Guinea-Bissau seen in a Nephrology appointment for monosymptomatic terminal hematuria is presented. The diagnosis of urinary schistosomiasis was confirmed by parasitological examination of urine and the pathological examination of bladder biopsies. After therapy with praziquantel, the patient became asymptomatic.

Field detection of Schistosoma japonicum cercariae in environmental water samples by quantitative PCR

A species-specific quantitative PCR (qPCR) assay was combined with two novel water-sampling methods and compared with the mouse bioassay for the quantitative detection of S. japonicum in surface waters. The novel methods were capable of capturing cercariae and, with subsequent analysis through qPCR, detecting the presence of a minimum of 1 cercaria.

The efficacy of NP11-4-derived immunotoxin scFv-artesunate in reducing hepatic fibrosis induced by Schistosoma japonicum in mice

Schistosomiasis is one of the most prevalent parasitic diseases in China, and hepatic fibrosis caused by schistosome infection is the principal cause of death. The aim of this study was to evaluate the efficacy of NP11-4-derived immunotoxin scFv-artesunate on Schistosoma japonicum-induced hepatic fibrosis. A single-chain variable fragment (scFv) was generated from the murine anti-Schistosoma japonicum (S. japanicum) monoclonal antibody NP11-4. The scFv was expressed as a soluble protein and purified by Ni-affinity chromatography. After conjugation with artesunate, the binding ability with soluble egg antigens (SEA) was determined by an enzyme-linked immunosorbent assay (ELISA). The biological activity of purified scFv, scFv-artesunate (immunotoxin), and artesunate was detected in vivo. Image-Pro Plus software was used to analyze the size of egg granuloma and the extent of liver fibrosis. The recombinant scFv expession vector was constructed and expressed successfully. After purification by a His-trap Ni-affinity column, the scFv yield was approximately 0.8 mg/L of culture medium. ELISA results showed that chemical conjugation did not affect the binding activity of the immunotoxin. Our animal experiments indicated that the immunotoxin could significantly reduce the size of egg granuloma in the liver and inhibit hepatic fibrosis. The immunotoxin could be used as a promising candidate in the targeted therapy of S. japonicum-induced hepatic fibrosis.

Oriental schistosomiasis with neurological complications: case report

We describe a case of cerebral schistosomiasis, caused by Asian (oriental) Schistosoma japonicum trematode blood flukes, in a young Chinese patient and its management. We also provide a brief update for physicians on the clinical features, diagnosis and treatment of schistosomiasis, with particular emphasis on neuroschistosomiasis, the most severe clinical outcome associated with this parasitic infection.

A catecholamine transporter from the human parasite Schistosoma mansoni with low affinity for psychostimulants

The trematode Schistosoma mansoni is the primary cause of schistosomiasis, a devastating neglected tropical disease that affects 200 million individuals. Identifying novel therapeutic targets for the treatment of schistosomiasis is therefore of great public interest. The catecholamines norepinephrine (NE) and dopamine (DA) are essential for the survival of the parasite as they cause muscular relaxation and a lengthening in the parasite and thereby control movement. Here we characterize a novel dopamine/norepinephrine transporter (SmDAT) gene transcript, from S. mansoni. The SmDAT is expressed in the adult form and in the sporocyst form (infected snails) of the parasite, and also in the egg and miracidium stage. It is absent in the cercariae stage but curiously a transcript missing the exon encoding transmembrane domain 8 was identified in this stage. Heterologous expression of the cDNA in mammalian cells resulted in saturable, dopamine transport activity with an apparent affinity for dopamine comparable to that of the human dopamine transporter. Efflux experiments reveal notably higher substrate selectivity compared with its mammalian counterparts as amphetamine is a much less potent efflux elicitor against SmDAT compared to the human DAT. Pharmacological characterization of the SmDAT revealed that most human DAT inhibitors including psychostimulants such as cocaine were significantly less potent in inhibiting SmDAT. Like DATs from other simpler organisms the pharmacology for SmDAT was more similar to the human norepinephrine transporter. We were not able to identify other dopamine transporting carriers within the completed parasite genome and we hypothesize that the SmDAT is the only catecholamine transporter in the parasite and could be responsible for not only clearing DA but also NE.

Schistosoma mansoni infection: an immune complex disease presenting with polyarthritis

Schistosomiasis or bilharzia is a parasitic disease found in tropical countries. Most infections are subclinical but may progress to chronic form characterized most frequently by the presence of liver involvement and portal hypertension. We report a patient that presented chronic polyarthritis with positive rheumatoid factor. During investigation, increased liver enzymes, negative hepatitis serologies and signs of portal hypertension on an ultrasound examination raised suspicion of S. mansoni infection. We will discuss pathophysiology and clinical manifestations of S. mansoni infection with special attention to articular involvement.

Non-cirrhotic intrahepatic portal hypertension: associated gut diseases and prognostic factors

BACKGROUND/AIMS

Non-cirrhotic intrahepatic portal hypertension (NCIPH) is generally regarded to have a benign prognosis. We have studied a cohort followed-up at a tertiary referral center and postulate that gut-derived prothrombotic factors may contribute to the pathogenesis and prognosis of NCIPH.

METHODS

We retrospectively analyzed prognostic indicators in 34 NCIPH patients. We also searched for associated gut diseases.

RESULTS

Transplant-free survival in NCIPH patients from first presentation with NCIPH at 1, 5, and 10 years was 94% (SE: 4.2%), 84% (6.6%), and 69% (9.8%), respectively. Decompensated liver disease occurred in 53% of patients. Three (9%) patients had ulcerative colitis while five of 31 (16%) tested had celiac disease and on Kaplan-Meier analysis, celiac disease predicted reduced transplant-free survival (p=0.018). On multivariable Cox regression analysis, independent predictors of reduced transplant-free survival were older age at first presentation with NCIPH, hepatic encephalopathy, and portal vein thrombosis. Prevalence of elevated initial serum IgA anticardiolipin antibody (CLPA) was significantly higher in NCIPH (36% of patients tested), compared to Budd-Chiari syndrome (6%) (p=0.032, Fisher's exact test) and celiac disease without concomitant liver disease (0%) (p=0.007).

CONCLUSIONS

We have identified prognostic factors and report progression to liver failure in 53% of NCIPH patients followed-up at our center. Our data supports a role for intestinal disease in the pathogenesis of intrahepatic portal vein occlusion leading to NCIPH.

Synthesis of molluscicidal agent cyanolide a macrolactone from D-(-)-pantolactone

An efficient synthesis of potent molluscicidal agent cyanolide A, a glycosidic 16-membered macrolide, starting from D-(-)-pantolactone is reported. Highly stereoselective aldol, oxa-Michael addition, and Yamaguchi macrolactonization are the key steps in the present synthesis.

Schistosomiasis japonica control and research needs

Schistosomiasis japonica, a chronic and debilitating disease caused by the blood fluke Schistosoma japonicum, is still of considerable economic and public health concern in the People's Republic of China, the Philippines, and Indonesia. Despite major progress made over the past several decades with the control of schistosomiasis japonica in the aforementioned countries, the disease is emerging in some areas. We review the epidemiological status and transmission patterns of schistosomiasis japonica, placing it into a historical context, and discuss experiences and lessons with national control efforts. Our analyses reveal that an integrated control approach, implemented through intersectoral collaboration, is essential to bring down the prevalence and intensity of Schistosoma japonicum infections and disease-related morbidity, and to sustain these parameters at low levels. The need for innovation and a sufficiently flexible control approach to adapt interventions in response to the changing nature and challenges of schistosomiasis control from the initial phase of morbidity control to the final state of elimination is emphasised. The aim of the presentation and the analyses is to inspire researchers and disease control managers elsewhere in Asia, Africa, and the Americas to harness the experiences gained and the lessons presented here to improve the control and eventual elimination of schistosomiasis and parasitic diseases.

Helminth infections of the central nervous system occurring in Southeast Asia and the Far East

Although helminth infections of the central nervous system (CNS) are rare, their public health implications must not be neglected. Indeed, several helminth species can cause cerebrospinal infections, especially if humans serve as intermediate or non-permissive host. The diagnosis of cerebrospinal helminthiases is difficult, and the detection of parasites in cerebrospinal fluid is rarely successful. Cerebrospinal helminth infections therefore often remain undetected, and hence prognosis is poor. Increases in tourism and population movements are risk factors for cerebrospinal helminthiases and infections pose particular challenges to clinicians in non-endemic areas. In this review, we focus primarily on food-borne helminthiases that are endemic and often emerging in Southeast Asia and the Far East, namely angiostrongyliasis, gnathostomiasis, sparganosis, paragonimiasis and cysticercosis. Additionally, we discuss neuroschistosomiasis, a disease that is transmitted through human-water contact. For each disease, we describe the pathogen, its transmission route and possible mechanisms for entering the CNS. We also summarise common signs and symptoms, challenges and opportunities for diagnosis, treatment, clinical management, geographical distribution and epidemiology. The adoption of a comprehensive set of diagnostic criteria for different cerebrospinal helminthiases is proposed, including epidemiological history, typical signs and symptoms, neuroimaging and laboratory findings. Finally, risk factors, and research needs for enhanced patient management and population-based control measures are discussed.

Genome-wide analyses reveal a role for peptide hormones in planarian germline development

Genomic/peptidomic analyses of the planarian Schmidtea mediterranea identifies >200 neuropeptides and uncovers a conserved neuropeptide required for proper maturation and maintenance of the reproductive system.

Bioactive peptides (i.e., neuropeptides or peptide hormones) represent the largest class of cell-cell signaling molecules in metazoans and are potent regulators of neural and physiological function. In vertebrates, peptide hormones play an integral role in endocrine signaling between the brain and the gonads that controls reproductive development, yet few of these molecules have been shown to influence reproductive development in invertebrates. Here, we define a role for peptide hormones in controlling reproductive physiology of the model flatworm, the planarian Schmidtea mediterranea. Based on our observation that defective neuropeptide processing results in defects in reproductive system development, we employed peptidomic and functional genomic approaches to characterize the planarian peptide hormone complement, identifying 51 prohormone genes and validating 142 peptides biochemically. Comprehensive in situ hybridization analyses of prohormone gene expression revealed the unanticipated complexity of the flatworm nervous system and identified a prohormone specifically expressed in the nervous system of sexually reproducing planarians. We show that this member of the neuropeptide Y superfamily is required for the maintenance of mature reproductive organs and differentiated germ cells in the testes. Additionally, comparative analyses of our biochemically validated prohormones with the genomes of the parasitic flatworms Schistosoma mansoni and Schistosoma japonicum identified new schistosome prohormones and validated half of all predicted peptide-encoding genes in these parasites. These studies describe the peptide hormone complement of a flatworm on a genome-wide scale and reveal a previously uncharacterized role for peptide hormones in flatworm reproduction. Furthermore, they suggest new opportunities for using planarians as free-living models for understanding the reproductive biology of flatworm parasites.

Flatworms cause diseases affecting hundreds of millions of people, so understanding what influences their reproductive activity is of fundamental importance. Neurally derived signals have been suggested to coordinate sexual reproduction in free-living flatworms, yet the neuroendocrine signaling repertoire has not been characterized comprehensively for any flatworm. Neuropeptides are a large diverse group of cell-cell signaling molecules and play many roles in vertebrate reproductive development; however, little is known about their function in reproductive development among invertebrates. Here we use biochemical and bioinformatic techniques to identify bioactive peptides in the genome of the planarian flatworm Schmidtea mediterranea and identify 51 genes encoding >200 peptides. Analysis of these genes in both sexual and asexual strains of S. mediterranea identified a neuropeptide Y superfamily member as important for the normal development and maintenance of the planarian reproductive system. We suggest that understanding peptide hormone function in planarian reproduction could have practical implications in the treatment of parasitic flatworms.

Detection of early and single infections of Schistosoma japonicum in the intermediate host snail, Oncomelania hupensis, by PCR and loop-mediated isothermal amplification (LAMP) assay

Polymerase chain reaction (PCR) with the specific primer set amplifying 28S ribosomal DNA (rDNA) of Schistosoma japonicum was able to detect genomic DNA of S. japonicum, but not S. mansoni, at 100 fg. This procedure enabled us to detect the DNA from a single miracidium and a snail infected with one miracidium at just 1 day after infection. We compared these results with those from loop-mediated isothermal amplification (LAMP) targeting 28S rDNA and found similar results. The LAMP could amplify the specific DNA from a group of 100 normal snails mixed with one infected snail A PCR screening of infected snails from endemic regions in Anhui Province revealed schistosomal DNA even in snails found negative by microscopy. PCR and LAMP show promise for monitoring the early infection rate in snails, and they may be useful for predicting the risk of infection in the endemic places.

Survival in schistosomiasis-associated pulmonary arterial hypertension

OBJECTIVES

The objective of this study was to evaluate the natural history of untreated schistosomiasis-associated pulmonary arterial hypertension (Sch-PAH) patients as compared to idiopathic pulmonary arterial hypertension (IPAH) with respect to hemodynamics recorded at presentation and 36 months survival.

BACKGROUND

Schistosomiasis (Sch) is one of the most prevalent chronic infectious diseases in the world. Nevertheless data regarding one of its most severe clinical complications, pulmonary arterial hypertension (PAH), is scarce.

METHODS

We retrospectively analyzed case notes of all consecutive patients diagnosed of Sch-PAH and IPAH referred to the Heart Institute in São Paulo, Brazil, between 2004 and 2008. None of the Sch-PAH received PAH specific treatment whereas all IPAH patients did.

RESULTS

Sch-PH patients (n = 54) had less severe pulmonary hypertension as evidenced by lower levels of pulmonary vascular resistance (11.3 +/- 11.3 W vs. 16.7 +/- 10.6 W; p = 0.002) and mean pulmonary artery pressure (56.7 +/- 18.7 mm Hg vs. 64.6 +/- 17.4 mm Hg; p = 0.01) and higher cardiac output (4.62 +/- 1.5 l/min vs. 3.87 +/- 1.5 l/min; p = 0.009) at presentation than IPAH patients (n = 95). None of the Sch-PAH patients demonstrated a positive response to acute vasodilator testing, whereas 16.2% of IPAH patients did (p = 0.015). Survival rates at 1, 2, and 3 years were 95.1%, 95.1%, and 85.9% and 95%, 86%, and 82%, for Sch-PAH and IPAH, respectively (p = 0.49). Both groups had a higher survival rate when compared to IPAH survival as estimated by the NIH equation (71%, 61%, and 52%, respectively).

CONCLUSIONS

Sch-PAH has a more benign clinical course than IPAH despite a lack of demonstrable acute vasoreactivity at hemodynamic evaluation.

Construction, purification, and evaluation of multivalent DNA vaccine against Schistosoma japonicum

DNA vaccine encoding a multivalent antigen is a novel approach of protective immunization. Four Schistosoma japonicum candidate antigen genes, glyceraldehyde-3-phosphate dehydrogenase (SjGAPDH), 23 kDa transmembrane protein (Sj23), 14 kDa fatty-acid binding protein (SjFABP) and 26 kDa glutathione-S-transferase (Sj26), are recombined into two pieces of fusion genes SjFABP.Sj23 and Sj26.SjGAPDH, respectively. Tetravalent DNA vaccine pVIVO2-SjFABP.Sj23/Sj26.SjGAPDH is constructed by co-expressing these two fusion genes. The super-coiled DNA vaccines for large-scale clinic application were purified by sequential chromatographies including group separation chromatography and affinitive chromatographies. The purified DNA vaccines were evaluated for in vivo and in vitro transfection assay. The immunoprotective properties of the different kinds of constructed DNA vaccines were appraised by pharmacological trials. The pharmacological trials results showed that tetravalent DNA vaccine has higher protective efficiency than other tested DNA vaccines.

Metabolic changes reveal the development of schistosomiasis in mice

Schistosomiasis is a parasitic zoonosis caused by small trematode worms called schistosomes, amongst which Schistosoma japonicum (S. japonicum) is endemic in Asia. In order to understand the schistosome-induced changes in the host metabolism so as to facilitate early diagnosis of schistosomiasis, we systematically investigated the dynamic metabolic responses of mice biofluids and liver tissues to S. japonicum infection for five weeks using ¹H NMR spectroscopy in conjunction with multivariate data analysis. We were able to detect schistosomiasis at the third week post-infection, which was one week earlier than “gold standard” methods. We found that S. japonicum infection caused significant elevation of urinary 3-ureidopropionate, a uracil catabolic product, and disturbance of lipid metabolism, stimulation of glycolysis, depression of tricarboxylic acid cycle and disruption of gut microbiota regulations. We further found that the changes of 3-ureidopropionate and overall metabolic changes in both urinary and plasma samples were closely correlated with the time-course of disease progression. Furthermore, such changes together with liver tissue metabonome were clearly associated with the worm-burdens. These findings provided more insightful understandings of host biological responses to the infection and demonstrated that metabonomic analysis is potentially useful for early detection of schistosomiasis and comprehension of the mechanistic aspects of disease progression.

Schistosomiasis is an infectious disease resulting from the infection of parasitic trematode worms called schistosomes. About 600 million people are currently exposed to schistosomiasis and 200 million people are infected in about 76 countries. Current diagnostic methods are unable to detect schistosomiasis at its early stages and thus are incapable of preventing disease causing further complications. In order to understand the effects of schistosome infection on hosts' biochemistry associated with disease progression in a holistic fashion and detect the infection at the early stage, we systematically investigated the metabolite composition (metabonome) changes in mice biofluids and liver tissues induced by Schistosoma japonicum using NMR spectroscopy. We detected infection-induced mice metabonomic alterations at three weeks post-infection, a week earlier than traditional methods. We found that the infection-caused elevation of urinary 3-ureidopropionate was not only associated with disease progression but also worm burden. We further found that overall metabonomic changes were also closely associated with disease progression, and our methods were capable of distinguishing different levels of worm burden at week five post-infection. Our findings provided further understandings in host responses to the infection and demonstrated metabonomics as a potentially useful tool for early diagnosis of S. japonicum infections.