Schistosomiasis Endemic Areas Research Articles

The Influence of HIV and Schistosomiasis on Renal Function: A Cross-sectional Study among Children at a Hospital in Tanzania

BackgroundSchistosomiasis and HIV are both associated with kidney disease. Prevalence and factors associated with abnormal renal function among HIV-infected children in Africa compared to uninfected controls have not been well described in a schistosomiasis endemic area.Methodology/Principal FindingsThis cross-sectional study was conducted at the Sekou Toure Regional Hospital HIV clinic in Mwanza, Tanzania. A total of 122 HIV-infected children and 122 HIV-uninfected siblings were consecutively enrolled. Fresh urine was obtained for measurement of albuminuria and Schistosoma circulating cathodic antigen. Blood was collected for measurement of serum creatinine. Estimated glomerular filtration rate (eGFR) was calculated using the modified Schwartz equation. Renal dysfunction was defined operationally as eGFR<60mL/min/1.73m2 and/or albuminuria>20mg/L in a single sample. Among 122 HIV-infected children, 61/122 (50.0%) met our criteria for renal dysfunction: 54/122 (44.3%) had albuminuria>20mg/L and 9/122 (7.4%) had eGFR<60. Among 122 HIV-uninfected children, 51/122 (41.8%) met our criteria for renal dysfunction: 48/122 (39.3%) had albuminuria>20mg/L and 6/122 (4.9%) had eGFR<60. Schistosomiasis was the only factor significantly associated with renal dysfunction by multivariable logistic regression (OR = 2.51, 95% CI 1.46–4.31, p = 0.001).Conclusions/SignificanceA high prevalence of renal dysfunction exists among both HIV-infected Tanzanian children and their HIV-uninfected siblings. Schistosomiasis was strongly associated with renal dysfunction.

Real-time PCR demonstrates high prevalence of Schistosoma japonicum in the Philippines: implications for surveillance and control.

BackgroundThe Philippines has a population of approximately 103 million people, of which 6.7 million live in schistosomiasis-endemic areas with 1.8 million people being at risk of infection with Schistosoma japonicum. Although the country-wide prevalence of schistosomiasis japonica in the Philippines is relatively low, the prevalence of schistosomiasis can be high, approaching 65% in some endemic areas. Of the currently available microscopy-based diagnostic techniques for detecting schistosome infections in the Philippines and elsewhere, most exhibit varying diagnostic performances, with the Kato-Katz (KK) method having particularly poor sensitivity for detecting low intensity infections. This suggests that the actual prevalence of schistosomiasis japonica may be much higher than previous reports have indicated.Methodology/Principal FindingsSix barangay (villages) were selected to determine the prevalence of S. japonicum in humans in the municipality of Palapag, Northern Samar. Fecal samples were collected from 560 humans and examined by the KK method and a validated real-time PCR (qPCR) assay. A high S. japonicum prevalence (90.2%) was revealed using qPCR whereas the KK method indicated a lower prevalence (22.9%). The geometric mean eggs per gram (GMEPG) determined by the qPCR was 36.5 and 11.5 by the KK. These results, particularly those obtained by the qPCR, indicate that the prevalence of schistosomiasis in this region of the Philippines is much higher than historically reported.Conclusions/SignificanceDespite being more expensive, qPCR can complement the KK procedure, particularly for surveillance and monitoring of areas where extensive schistosomiasis control has led to low prevalence and intensity infections and where schistosomiasis elimination is on the horizon, as for example in southern China.

Development and optimization of cocktail-ELISA for a unified surveillance of zoonotic schistosomiasis in multiple host species.

The zoonotic characteristic of the human parasite Schistosoma japonicum infecting a significant number of wild and domestic animals highlights the need to develop a unified surveillance in multiple host species for a strengthened schistosomiasis control. It has been shown in several studies that water buffaloes and dogs are considered important reservoirs in the transmission of the schistosome parasite to humans. Recombinant antigens like thioredoxin peroxidase-1 (SjTPx-1) and tandem repeat proteins (Sj1TR, Sj7TR) have been shown to be good diagnostic antigens individually in humans, water buffaloes, and dogs in previous studies. Mixing these antigens together in a cocktail-ELISA might not only improve their diagnostic potentials but rather produce a multi-host species detection means for zoonotic schistosomiasis. In this study, we aimed to develop and optimize cocktail-ELISA by testing different combinations of these recombinant antigens in humans, water buffaloes, and dogs. As compared with the diagnostic potential calculated for each of the three recombinant antigens used, their combination has presented improved specificities, positive predictive values, and kappa values. Using samples collected from various endemic areas in the Philippines, results showed that the combination of SjTPx-1/Sj7TR/Sj1TR has the highest sensitivity in humans (84.1 %), water buffaloes, and dogs (80 %) and specificity (100 %) in all host species. This study therefore suggests the use of cocktail-ELISA in improving the zoonotic surveillance in schistosomiasis endemic areas.

Schistosomiasis transmission and control in China

In the last 60 years, great progress has been made in controlling and preventing schistosomiasis in China. However, due to the ecosystem changes caused by the construction of the Three Gorges Dams and the South-north Water Conversion Project, the effects of climate change, the scarcity of a highly sensitive surveillance and response system, schistosomiasis is still considered as a major public health problem and is listed among the top infectious diseases in the country prioritized for control and elimination. Based on the epidemiological pattern of schistosomiasis and ecological characteristics of the vector snail, endemic areas of schistosomiasis in China were categorized into three types: (i) plain region with waterway networks, (ii) mountainous and hilly regions, and (iii) marshland and lake regions. China aims to reach the criteria of transmission control threshold of less than 1% in the lake and marshland provinces and reach transmission interruption threshold in hilly provinces of Sichuan and Yunnan by the end of 2015. The purpose of this article is to use the deterministic model proposed in our earlier study in (Chen et al., 2010) to simulate the schistosomiasis infection data from other lake and marshland provinces, including Hunan, Jiangxi and Anhui. Our simulations demonstrate that the model can reasonably mimic the schistosomiasis infection data from these lake and marshland provinces. Thus, similar control and prevention measures can be designed and proposed for these provinces. We will also try to use the model to simulate the schistosomiasis infection data from Sichuan and Yunnan provinces in the mountainous and hilly regions where cattle farming is not as popular and important as in the lake and marshland provinces and find out that different control and prevention strategies are required.

A loop-mediated isothermal amplification (LAMP) assay for early detection of Schistosoma mansoni in stool samples: a diagnostic approach in a murine model.

BackgroundHuman schistosomiasis, mainly due to Schistosoma mansoni species, is one of the most prevalent parasitic diseases worldwide. To overcome the drawbacks of classical parasitological and serological methods in detecting S. mansoni infections, especially in acute stage of the disease, development of cost-effective, simple and rapid molecular methods is still needed for the diagnosis of schistosomiasis. A promising approach is the loop-mediated isothermal amplification (LAMP) technology. Compared to PCR-based assays, LAMP has the advantages of reaction simplicity, rapidity, specificity, cost-effectiveness and higher amplification efficiency. Additionally, as results can be inspected by the naked eye, the technique has great potential for use in low-income countries.Methodology/Principal findingsA sequence corresponding to a mitochondrial S. mansoni minisatellite DNA region was selected as a target for designing a LAMP-based method to detect S. mansoni DNA in stool samples. We used a S. mansoni murine model to obtain well defined stool and sera samples from infected mice with S. mansoni cercariae. Samples were taken weekly from week 0 to 8 post-infection and the Kato-Katz and ELISA techniques were used for monitoring the infection. Primer set designed were tested using a commercial reaction mixture for LAMP assay and an in house mixture to compare results. Specificity of LAMP was tested using 16 DNA samples from different parasites, including several Schistosoma species, and no cross-reactions were found. The detection limit of our LAMP assay (SmMIT-LAMP) was 1 fg of S. mansoni DNA. When testing stool samples from infected mice the SmMIT-LAMP detected S. mansoni DNA as soon as 1 week post-infection.Conclusions/SignificanceWe have developed, for the first time, a cost-effective, easy to perform, specific and sensitive LAMP assay for early detection of S. mansoni in stool samples. The method is potentially and readily adaptable for field diagnosis and disease surveillance in schistosomiasis-endemic areas.

Cancer risks and long-term community-level exposure to pentachlorophenol in contaminated areas, China.

Widespread use of pentachlorophenol (PCP) in schistosomiasis endemic areas had led to ubiquitous exposure to PCP and its residues. Numerous studies had revealed that occupational PCP exposure probably increased risk of cancers, but whether long-term community-level exposure to PCP generates the similarly carcinogenic effect, seldom studies focused on it. This study was to explore the cancer risks of long-term community-level PCP exposure from drinking water in a Chinese general population. Incident (2009-2012) cancer records were identified by local government national registry. And PCP concentration of raw drinking water samples in each district was measured by GC-MS/MS analysis for further division of three PCP exposure categories by interquartile range (high vs. medium vs. low). Internal comparisons were performed, and standard rate ratio was calculated to describe the relationship between PCP exposure and cancer risks by using low-exposure group as the reference group. PCP was detected in all 27 raw drinking water samples ranging from 11.21 to 684.00 ng/L. A total of 6,750 cases (4,409 male and 2,341 female cases) were identified, and age-standardized rate (world) was 154.95 per 100,000 person-years. The cancer incidence for the high-exposure group was remarkably high. Internal comparisons indicated that high PCP exposure might be positively associated with high cancer risks in the community population, particularly for leukemia (SRR = 5.93, 95 % CI = 5.24-6.71), maligant lymphoma (SRR = 2.27, 95 % CI = 2.10-2.54), and esophageal cancer (SRR = 2.42, 95 % CI = 2.35-2.50). Long-term community-level exposure to PCP was probably associated with hemolymph neoplasm, neurologic tumors, and digestive system neoplasm.

A hybrid model for predicting the prevalence of schistosomiasis in humans of Qianjiang City, China.

Backgrounds/ObjectiveSchistosomiasis is still a major public health problem in China, despite the fact that the government has implemented a series of strategies to prevent and control the spread of the parasitic disease. Advanced warning and reliable forecasting can help policymakers to adjust and implement strategies more effectively, which will lead to the control and elimination of schistosomiasis. Our aim is to explore the application of a hybrid forecasting model to track the trends of the prevalence of schistosomiasis in humans, which provides a methodological basis for predicting and detecting schistosomiasis infection in endemic areas.MethodsA hybrid approach combining the autoregressive integrated moving average (ARIMA) model and the nonlinear autoregressive neural network (NARNN) model to forecast the prevalence of schistosomiasis in the future four years. Forecasting performance was compared between the hybrid ARIMA-NARNN model, and the single ARIMA or the single NARNN model.ResultsThe modelling mean square error (MSE), mean absolute error (MAE) and mean absolute percentage error (MAPE) of the ARIMA-NARNN model was 0.1869×10−4, 0.0029, 0.0419 with a corresponding testing error of 0.9375×10−4, 0.0081, 0.9064, respectively. These error values generated with the hybrid model were all lower than those obtained from the single ARIMA or NARNN model. The forecasting values were 0.75%, 0.80%, 0.76% and 0.77% in the future four years, which demonstrated a no-downward trend.ConclusionThe hybrid model has high quality prediction accuracy in the prevalence of schistosomiasis, which provides a methodological basis for future schistosomiasis monitoring and control strategies in the study area. It is worth attempting to utilize the hybrid detection scheme in other schistosomiasis-endemic areas including other infectious diseases.

A multivalent chimeric vaccine composed of Schistosoma mansoni SmTSP-2 and Sm29 was able to induce protection against infection in mice.

Schistosoma mansoni is a blood fluke parasite responsible for schistosomiasis. The best long-term strategy to control schistosomiasis is through immunization combined with drug treatment. In this study, we cloned, expressed and purified SmTSP-2 fused to the N- and C-terminal halves of Sm29 and tested these chimeras as vaccine candidates using an adjuvant approved to be used in humans. The results demonstrated that vaccination with SmTSP-2 fused to N- or C-terminus of Sm29-induced reduction in worm burden and liver pathology when compared to control animals. Additionally, we detected high levels of mouse-specific IgG, IgG1 and IgG2a against both chimeras and significant amounts of IFN-γ and TNF-α and no IL-4. Finally, studies with sera from patients resistant to infection and living in schistosomiasis endemic areas revealed high levels of specific IgG to both chimeras when compared to healthy individuals. In conclusion, SmTSP-2/Sm29 chimeras tested here induced partial protection against infection and might be a potential vaccine candidate.

A cross-sectional study on urogenital schistosomiasis in children; haematuria and proteinuria as diagnostic indicators in an endemic rural area of Nigeria.

Rapid and accurate diagnosis is necessary for the management of schistosomiasis in endemic areas. To assess the burden of urogenital schistosomiasis and the diagnostic efficiency of morbidity indicators of the disease in an endemic rural community of Nigeria. A cross-sectional school-based study was conducted. Urine samples of 487 pupils were screened microscopically for S. haematobium and tested for haematuria and proteinuria using chemical reagent strips. The prevalence and intensity of infection were 57.1% and 45.0 eggs/10 mL urine respectively. Prevalence of infection in male (54.1%) and female (60.3%) individuals showed no significant variation (P>0.05). However, prevalence of infection was age dependent with those in age groups 3-5 and 12-14 years having the least and highest prevalence of infection respectively (P<0.05). Microhaematuria and proteinuria varied significantly with ages of the pupils with least (14.0, 40.0%) and highest (60.0, 80.0%) prevalence recorded in age groups 3-5 and 15-19 years respectively (P<0.05). Proteinuria showed higher sensitivity (80.3%) compared to microhaematuria (73.3%). Schistosomiasis is highly endemic in the study area and the use of microhaematuria and proteinuria for mapping the infected population prior treatment could be adopted.

Chlamydia Trachomatis and Neisseria Gonorrhoeae prevalence among women of reproductive age living in urogenital schistosomiasis endemic area in Ghana.

BackgroundMany studies have shown an overlap in the epidemiology of sexually transmitted infections (STIs) and urogenital schistosomiasis among young women living in schistosomiasis endemic areas. Yet we found no study assessing the prevalence of STI infections in urogenital schistosomiasis endemic areas in Ghana. As part of an epidemiological study on urogenital schistosomiasis and HIV, we sought to assess the prevalence of both Chlamydia trachomatis (CT) and Neisseria gonorhoeae (NG) infections among women living in schistosomiasis endemic communities and explore the relationship between the sexually transmitted infections (STIs) and demographic characteristics, sexual behaviour and self-reported symptoms.MethodsThis was a cross-sectional study in which endocervical samples were collected from 191 women aged 15–49 years from October 2005 to March 2006. Samples were examined for CT and NG using Polymerase Chain Reaction (PCR). A structured questionnaire was also used to elicit information on study participant’s gynaecological and obstetric history and symptoms for genital infection. Chi-square test and binary logistic regression were used to assess association between CT and NG and other variables such as age, sexual behaviour and self-reported symptoms.ResultsThe overall prevalence of CT and NG were 6.3% and 2.6% respectively.The highest prevalence rates of CT were in the 15 to 19 year group while only individuals between 15 and 39 years were positive for NG. There was no association between CT and age, contraceptive use and the other variables assessed. NG on the other hand was found to be associated with age, number of births and number of sexual partners only by chi-square test.ConclusionsOur research revealed higher prevalence of CT and NG infections when compared to previous studies conducted among higher risk groups in non-urogenital schistosomiasis areas in Ghana. We therefore recommend further studies of these STIs in urogenital schistosomiasis endemic areas in the country.

Knowledge of, attitudes towards, and practice relating to schistosomiasis in two subtypes of a mountainous region of the People's Republic of China.

BackgroundSchistosomiasis japonica is still endemic in the People’s Republic of China (P.R. China) in five provinces of lake and marshland regions and in two provinces of mountainous regions. Studies elucidated that individual and community perception, attitudes towards schistosomiasis, and hygiene behaviors were crucial factors for preventing schistosomiasis. This study sought to assess the knowledge of, attitudes towards, and practices (KAP) relating to schistosomiasis in two subtypes of a mountainous region in Eryuan County, Yunnan Province, P.R. China. The study’s aim is to make suggestions for establishing more specific and effective control measures for disease transmission and interruption in two subtypes of a mountainous region with low-level infection rates.MethodsA cross-sectional study of 3,000 inhabitants was carried out in the Yongle (plateau basin) and Xinzhuang (plateau canyon) communities of Eryuan County, Yunnan Province in November and December 2011. Stratified cluster random sampling was undertaken using a uniform set of quantitative questionnaires administered by trained assistants. This was further supported with qualitative data from in-depth interviews (IDIs) conducted with ten farmers and ten students. All participants were examined for schistosomiasis using both a serological test (indirect hemagglutination assay [IHA]) and a stool examination (Kato-Katz).ResultsThe total schistosomiasis knowledge rate in Yongle (83.4%) was significantly lower than that in Xinzhuang (95.5%). In both communities, among the respondents aged 15 years or below, more than one third didn’t know the name, endemic areas, and animal reservoirs of schistosomiasis. The majority of respondents in Eryuan acquired their schistosomiasis knowledge from doctors, followed by handouts and hearing from others. The infection rate was once the highest in Yongle, but is now the highest in Xinzhuang, where there are more risk factors for schistosomiasis, such as frequently grazing cattle, digging vegetables or cutting grass in the field, as well as raising cattle by free grazing.ConclusionIn short, Eryuan County’s overall knowledge rate of schistosomiasis was found to be high. Due to various dominating risk factors, different control strategies should be designed keeping in mind the two different subtypes of endemic areas for schistosomiasis in mountainous regions, namely plateau basins and plateau canyons.

Thrombocytopenia as a surrogate marker of hepatosplenic schistosomiasis in endemic areas for Schistosomiasis mansoni.

This study aimed to evaluate whether a low platelet count is a good surrogate marker of hepatosplenic schistosomiasis (HSS) in a rural area of Brazil. A small district in southeastern Brazil, with a population of 1,543 individuals and a 23% prevalence of schistosomiasis, was selected for this investigation. In July 2012, 384 volunteers were subjected to clinical, ultrasonography (US), and laboratory examinations, including stool sample analysis. The HSS patients were classified into four groups: Group 1 consisted of patients with a spleen >13cm and liver fibrosis; Group 2 consisted of patients with a palpable spleen and spleen>13cm measured by US; Group 3 consisted of patients with a spleen >13cm measured by US; and Group 4 consisted of patients with a palpable spleen. Eight patients were in Group 1 (2.1%), twenty-one were in Group 2 (5.5%), eight were in Group 3 (2.1%), and eighteen were in Group 4 (4.7%). A significant difference in the mean platelet counts was observed between the patients with and without HSS (p<0.01). Based on the receiver operating characteristic (ROC) curve (platelet count <143,000/mm3), the sensitivity was greater than 92% in all groups, and the specificity varied from 44.4% to 75%. We concluded that in endemic areas, thrombocytopenia demonstrates good sensitivity for detecting HSS and may be used as a screening tool to identify patients with HSS.

An Immunomics Approach to Schistosome Antigen Discovery: Antibody Signatures of Naturally Resistant and Chronically Infected Individuals from Endemic Areas

Schistosomiasis is a neglected tropical disease that is responsible for almost 300,000 deaths annually. Mass drug administration (MDA) is used worldwide for the control of schistosomiasis, but chemotherapy fails to prevent reinfection with schistosomes, so MDA alone is not sufficient to eliminate the disease, and a prophylactic vaccine is required. Herein, we take advantage of recent advances in systems biology and longitudinal studies in schistosomiasis endemic areas in Brazil to pilot an immunomics approach to the discovery of schistosomiasis vaccine antigens. We selected mostly surface-derived proteins, produced them using an in vitro rapid translation system and then printed them to generate the first protein microarray for a multi-cellular pathogen. Using well-established Brazilian cohorts of putatively resistant (PR) and chronically infected (CI) individuals stratified by the intensity of their S. mansoni infection, we probed arrays for IgG subclass and IgE responses to these antigens to detect antibody signatures that were reflective of protective vs. non-protective immune responses. Moreover, probing for IgE responses allowed us to identify antigens that might induce potentially deleterious hypersensitivity responses if used as subunit vaccines in endemic populations. Using multi-dimensional cluster analysis we showed that PR individuals mounted a distinct and robust IgG1 response to a small set of newly discovered and well-characterized surface (tegument) antigens in contrast to CI individuals who mounted strong IgE and IgG4 responses to many antigens. Herein, we show the utility of a vaccinomics approach that profiles antibody responses of resistant individuals in a high-throughput multiplex approach for the identification of several potentially protective and safe schistosomiasis vaccine antigens.

Schistosoma mansoni in schoolchildren in a Madagascan highland school assessed by PCR and sedimentation microscopy and Bayesian estimation of sensitivities and specificities

Madagascar is an endemic area for schistosomiasis, but recent prevalence data are scarce. We investigated stool samples of 410 children aged 4–18 years from a combined primary and secondary school in a Madagascan highland village near Ambositra in order to assess the prevalence of Schistosoma mansoni using microscopy and real-time polymerase chain reaction (PCR). A high prevalence of S. mansoni of 77.1% was detected by PCR, while only 15.2% of microscopic examinations of sedimentation-enriched stools were positive. We estimated the sensitivity and specificity of stool sedimentation microscopy (19.7% and 98.8%) and of PCR (98.9% and 89.3%) using a Bayesian approach for two dependant tests in one population without a reference standard. Our Bayesian posterior estimate of the prevalence is 80.2%. Simple sedimentation technique misses about 4/5 of all PCR-confirmed infections and is insufficient to determine the prevalence of S. mansoni. A survey comparing PCR with a classical standard technique (KatoKatz) is desirable.

Serodiagnosis of Schistosoma japonicum infection: genome-wide identification of a protein marker, and assessment of its diagnostic validity in a field study in China

Schistosomiasis remains a highly prevalent and serious parasitic disease. A major factor preventing its effective management is the scarcity of effective diagnostic tools. We did a genome-wide identification of diagnostic protein markers for schistosome infection and assessed their diagnostic validity in a field study. We predicted putative secreted proteins of Schistosoma japonicum (SjSPs) and expressed them as glutathione S-transferase (GST)-fusion proteins. The fusion proteins were arrayed on glutathione (GSH)-immobilised microplates and screened with serum samples from patients with schistosomiasis diagnosed by the Kato-Katz method. We further assessed an identified protein marker for sensitivity and specificity, first in infected serum samples collected from Jiangxi and Hunan Provinces, China, and then through a field study, done in two villages located in a high schistosomiasis-endemic area of the southeast of China. Of 204 recombinant proteins, 35 yielded seropositive reactions, eight showed strong immunoreactivity, and only one (SjSP-13) reacted to the entire panel of 14 archived samples. The reactivity of SjSP-13 to 476 serum samples showed 90·4% (95% CI 86·5-93·5) sensitivity and 98·9% (95% CI 95·9-99·9) specificity. Of 1371 residents enrolled in a field study from Dec 6, 2010, to June 23, 2011, only 74 individuals were identified as being egg-positive, whereas 465 were diagnosed as positive by the SjSP-13-based ELISA kit (rSP13-ELISA). Of the 394 individuals found egg-negative but rSP13-ELISA-positive, 363 (92·4%) were confirmed to be positive for schistosome infection by PCR detection of S japonicum SjR2 retrotransposon. The application of this sensitive, specific, and affordable rSP13-ELISA method should help reduce schistosomiasis transmission through targeted treatment of individuals, particularly with low intensity infections, and therefore support schistosomiasis control and elimination strategies. National 973 project in China.

Genital schistosomiasis and its unacknowledged role on HIV transmission in the STD intervention studies

Treatment of sexually transmitted infections (STIs) has been hypothesised to decrease HIV transmission. Although observational studies show an association between STIs and HIV, only one prospective randomised controlled trial (RCT) has confirmed this. Female genital schistosomiasis can cause genital lesions, accompanied by bloody discharge, ulcers or malodorous discharge. Genital schistosomiasis is common, starts before puberty and symptoms can be mistaken for STIs. Three observational studies have found an association between schistosomiasis and HIV. Genital lesions that develop in childhood are chronic. This paper sought to explore the possible effects of schistosomiasis on the RCTs of STI treatment for HIV prevention. In the study sites, schistosomiasis was a likely cause of genital lesions. The studies recruited women that may have had genital schistosomal lesions established in childhood. Schistosomiasis endemic areas with different prevalence levels may have influenced HIV incidence in intervention and control sites differently, and some control group interventions may have influenced the impact of schistosomiasis on the study results. Schistosomiasis is a neglected cause of genital tract disease. It may have been an independent cause of HIV incidence in the RCTs of STI treatment for HIV prevention and may have obscured the findings of these trials.

Evaluation of the use of C-terminal part of the Schistosoma mansoni 200 kDa tegumental protein in schistosomiasis diagnosis and vaccine formulation

Schistosoma mansoni tegument is involved in essential functions for parasite survival and represents a target for screening candidates for vaccine and diagnosis. Our group using reverse vaccinology selected six candidates, previously demonstrated by proteomics studies to be expressed in the parasite tegument, among them was Sm200. In this work we have cloned and expressed a recombinant form of Sm200 C-terminal (1069–1520) region. The efficacy of rSm200 (1069–1520) in the diagnosis of schistosomiasis and in the formulation of a vaccine against S. mansoni was assessed respectively in an ELISA based diagnostic assay and immunization protocols in mice. Significant differences between non-infected and acutely infected or chronically infected animals were observed and no cross-recognition was observed with sera from Ascaris suum or Ancylostoma ceylanicum infected mice. rSm200-ELISA test could also discriminate infected individuals from healthy donors not living in endemic area for schistosomiasis but failed to discriminate between individuals from a low endemic area for schistosomiasis known to have positive or negative stools after examination. Recombinant Sm200 also failed to induce protection against schistosomiasis, demonstrating that the C-terminal part of Sm200 is unable to induce protective immune response in mice. Therefore rSm200 (1069–1520)-ELISA represents an important tool to be used in the diagnosis of schistosomiasis.

Chronic hepatitis B and liver schistosomiasis: a deleterious association

Chronic hepatitis B (CHB) and schistosomiasis are prevalent in several countries, but the impact of this association is unknown. We aimed to investigate the prevalence and morbidity of this co-infection in Minas Gerais, an endemic area of schistosomiasis in Brazil. In total, 406 adults with CHB (HBsAg positive >6 months) were included in a cross-sectional study. CHB was classified as replicative (HBV DNA ≥ 2.000 IU/ml), and low replicative or inactive hepatitis B carriers (HBV DNA <2.000 IU/ml). Schistosomiasis was confirmed by epidemiological and clinical records. Liver biopsies were scored by METAVIR. The risk of severe fibrosis was estimated by multivariate analysis. Of the 406 patients, 64.8% (263) were male, and the median age was 45 years (IQR 35-54). In total, 57.9% (235) had replicative CHB, and 31.5% (128) had cirrhosis. Schistosoma mansoni was confirmed in 30.5% (124) patients, 81.5% (101) of which were male with a median age of 47 years (IQR 39.5-54). Of the co-infected patients, 61.3% (76) and 38.7% (48) had replicative and inactive CHB, respectively. Schistosomal portal fibrosis (PF) was detected in 69.4% (86/124) patients. Patients with replicative CHB and schistosomal PF had more advanced fibrosis and severe inflammation compared with patients without schistosomal PF (80.8% vs 43.6% for METAVIR F3-F4, p<0.01; 64.0% vs 39.8% for METAVIR A2-A3, p < 0.01). Age >50 years (OR = 1.10; 95% CI 1.06-1.14, p<0.001), male gender (OR = 2.61, 95% CI 1.12-6.09, p = 0.03), schistosomal PF (OR = 4.56, 95% CI 2.10-9.91, p<0.001) and alcoholism (OR = 2.46, 95% CI 1.16-5.19, p = 0.02) were independently associated with cirrhosis. The association between replicative CHB and schistosomal PF can be a risk factor for more severe liver disease, which can result in deleterious outcomes for patients from endemic areas.

Freshwater gastropods of the Baixada Maranhense Microregion, an endemic area for schistosomiasis in the State of Maranhão, Brazil: I - qualitative study

The Baixada Maranhense Microregion currently has the highest prevalence of schistosomiasis in the State of Maranhão, likely because this parasitosis is characterized as an occupational disease, and increased contact with water increases the risk of infection by Schistosoma mansoni. This paper reports the results of the first comprehensive freshwater malacological survey performed in the Baixada Maranhense Microregion. Freshwater mollusks were collected from the twenty-one municipalities of the Baixada Maranhense Microregion and from Bacurituba and Cajapió and were evaluated for infection by trematodes. A total of 9,129 mollusks were collected (sixteen species), which included the first records of six species in the State of Maranhão: Gundlachia radiata, G. ticaga, Hebetancylus moricandi, Plesiophysa guadeloupensis, Pomacea bridgesii diffusa and Omalonyx sp. Biomphalaria glabrata was found in five municipalities, whereas B. straminea was found in nine. Biomphalaria glabrata and B. straminea were observed in syntopy in Pinheiro and São Bento. Of the 990 specimens of B. glabrata and the 2,109 specimens of B. straminea that were exposed to and/or analyzed for the presence of larval trematodes, only a single specimen of B. glabrata (0.1%) from São Bento shed S. mansoni. Other larval trematodes were first observed in mollusks from the State of Maranhão. These results indicate that the study area is epidemiologically important due to the presence of two natural vectors of schistosomiasis and the active transmission of schistosomiasis, which was confirmed in the infected specimen that was collected in this study.

Proteinuria as a Morbidity Marker of Urinary Schistosomiasis in School Children Living in Onchocerciasis Endemic Areas of Benue State, Nigeria

Proteinuria is an indirect marker of urinary schistosomiasis in endemic areas but cases of misdiagnosis could occur in areas where other diseases that produce proteinuria overlap with urinary schistosomiasis. The study was conducted to assess whether proteinuria measured by urine reagent strips could be used as a rapid screening technique of urinary schistosomiasis in onchocerciasis endemic areas. Urine reagent strips and filtration technique were used to screen proteinuria and to determine Schistosoma haematobium eggs in 1,124 school children respectively. Our findings demonstrate that proteinuria positively correlated with intensity of infection (rho=0.71, p<0.01), highly sensitive (95.7%) and moderately specific (67.7%). We suggest that measuring proteinuria using urine reagent strips may be useful for diagnostic purposes, monitoring and evaluating urinary schistosomiasis in onchocerciasis endemic areas. Furthermore, we recommend that additional research should be done to further elucidate the relationship between proteinuria and pathological changes of the urinary tract that may be attributed to infection with Schistosoma haematobium in onchocerciasis endemic areas.