Schistosomiasis mansoni -- clinical features

An overview of qualitative and quantitative platelet abnormalities in schistosomiasis

Schistosomiasis is a neglected tropical disease referring to the infection with blood parasitic trematodes of the genus Schistosoma. It impacts millions of people worldwide, primarily in low-to-middle-income countries. Patients infected with schistosomiasis often exhibit a distinct hematological profile, including anemia, eosinophilia, thrombocytopenia, and coagulopathy. Platelets, essential components of the hemostatic system, play a crucial role in the pathogenesis of schistosomiasis. Schistosomes secrete serine proteases and express ectoenzymes, such as calpain protease, alkaline phosphatase (SmAP), phosphodiesterase (SmNPP5), ATP diphosphohydrolase (SmATPDase1), serine protease Sk1, SmSP2, and Sm22.6, which can interfere with platelet normal functioning. This report provides comprehensive, up-to-date information on platelet abnormalities observed in patients with schistosomiasis, highlighting their importance in the disease progression and complications. It delves into the interactions between platelets and schistosomes, including the impact of platelet dysfunction on hemostasis and immune responses, immune-mediated platelet destruction, and the potential mechanisms by which schistosome tegumental ectoenzymes affect platelets. Furthermore, the report clarifies the relationship between platelet abnormalities and clinical manifestations such as thrombocytopenia, coagulation disorders, and the emergence of portal hypertension and gastrointestinal bleeding. Understanding the complex interplay between platelets and schistosomes is crucial for improving patient management and outcomes in schistosomiasis, particularly for those with platelet alterations. This knowledge contributes to improved diagnostic methods, innovative treatment strategies, and global efforts to control and eliminate schistosomiasis.

Schistosoma mansoni Infections and Morbidities Among School Children in Hotspot Areas of Jimma Town, Southwest Ethiopia: A Cross-Sectional Study

BACKGROUND

Schistosoma mansoni is endemic in all regions of Ethiopia. School-age children are highly vulnerable to schistosomiasis-related morbidities. This study aimed to determine the prevalence of S. mansoni and morbidities among schoolchildren in schistosomiasis hotspot areas of Jimma Town.

METHODS

Cross-sectional study was conducted among schoolchildren in Jimma Town. Stool sample was examined using Kato-Katz for the detection of S. mansoni.

RESULTS

A total of 332 schoolchildren were included in the study. The prevalence of S. mansoni and STHs was 20.2% and 19.9%, respectively. Males (adjusted odds ratio (AOR) = 4.9; 95% CI: 2.4-10.1; p = .001), swimming habits (AOR = 3.0; 95% CI: 1.1-8.3; p = .033) and schools attended (AOR = 4.3; 95% CI: 1.4-13.6; p = .012, AOR = 3.8; 95% CI: 1.3-10.9; p = .014) were associated factors for S. mansoni infections. Blood in stool (AOR = 2.0; CI: 1.0-4.1; p = .045) and feeling general malaise (AOR = 4.0; CI: 1.4-11.3; p = .007) were significantly associated with S. mansoni infection-related morbidities. Moreover, prevalence of stunting among schoolchildren 6 to 11 years of age was 29.7% (71/239).

CONCLUSION

The transmission of S. mansoni among schoolchildren is moderate. Sex, swimming habits and schools attended were associated with S. mansoni infections. Blood in stool and general malaise were clinical characteristics associated with S. mansoni infections. Integration of health promotion is needed to achieve control and elimination goals. Attention should also be given to stunted growth of the children.

Natural History of Hepatosplenic Schistosomiasis (HSS) Non–Cirrhotic Portal Hypertension (NCPH): Influence of Gastrointestinal Bleeding and Decompensation in Prognosis

Background: Hepatosplenic schistosomiasis (HSS) is a peculiar form of non-cirrhotic portal hypertension (NCPH). Although HSS patients present normal hepatic function, some evolve signs of hepatocellular failure and features of decompensated cirrhosis. The natural history of HSS-NCPH is unknown. Methods: A retrospective study was conducted that evaluated patients who fulfilled clinical-laboratorial criteria for HSS. Results: A total of 105 patients were included. Eleven patients already presented with decompensated disease and had lower transplant-free survival at 5 years than those without (61% vs. 95%, p = 0.015). Among 94 patients without prior decompensation, the median follow-up was 62 months and 44% of them had varicose bleeding (two or more episodes in 27%). Twenty-one patients presented at least one episode of decompensation (10-year probability 38%). Upon multivariate analysis, varicose bleeding and higher bilirubin levels were associated with decompensation. The 10-year probability of survival was 87%. Development of decompensation and age were predictive of mortality. Conclusion: HSS is characterized by multiple episodes of GI bleeding, a high probability of decompensation and reduced survival at the end of the first decade. Decompensation is more common in patients with varicose esophageal bleeding and is associated with lower survival.

Misdiagnosis of Hepatosplenic Schistosomiasis as Hepatic Tuberculosis: A Case Report

We report a case of a 38-year-old woman who was initially misdiagnosed with hepatic tuberculosis and was managed as such before being correctly diagnosed with hepatosplenic schistosomiasis on liver biopsy. The patient had a five-year history of jaundice which over time was accompanied by polyarthritis and then abdominal pain. A diagnosis of hepatic tuberculosis was made clinically and supported by radiographic evidence. She underwent an open cholecystectomy for gallbladder hydrops with the liver biopsy taken revealing chronic hepatic schistosomiasis and was eventually started on praziquantel with good recovery. This case demonstrates a diagnostic issue with the radiographic presentation of the patient and the important role of tissue biopsy in providing definitive care.

The prevalence of Schistosoma mansoni infection among adults with chronic non-communicable diseases in Malawi

Background

Schistosomiasis is a parasitic infectious disease caused by flatworms of the Schistosoma genus. The global burden of schistosomiasis is high. In Malawi, schistosomiasis is among the top 20 causes of outpatient department visits in health facilities. Schistosomiasis is among the most important but neglected causes of non-communicable diseases (NCD) peculiar to tropical endemic settings. While much is known about the contribution of S. haematobium to the NCD burden in Malawi, the role of S. mansoni remains largely unknown.

Methods

We conducted a cross-sectional study at Mangochi District Hospital. Adults over 18 years diagnosed with NCDs (n = 414), admitted or attending weekly outpatient clinics were recruited between August 2021 and February 2022. Data were collected on sociodemographic characteristics, medical history, body weight, blood pressure, and fasting blood glucose. Stool and midstream urine were collected for Kato–Katz (KK) microscopy and urine point of care-circulating cathodic antigen (POC-CCA) tests, respectively. We computed prevalence of S. mansoni as number of positive KK and CCA tests, each divided by total submitted samples. Univariate and multivariable logistic regression were done to evaluate risk factors of NCDs and association between S. mansoni infection and NCDs.

Results

We recruited 414 participants, mean age 57 years (SD 16), 67% of whom were female. Prevalence of S. mansoni based on urine CCA was 15% (95% CI: 11–19) and 0% on KK microscopy. Hypertension was the most common condition with a prevalence of 85% (95% CI: 81–89), followed by diabetes mellitus with a prevalence of 42% (95% CI: 37–46) and heart disease with a prevalence of 3% (95% CI: 2–5). S. mansoni infection was not significantly associated with hypertension (OR: 1.2, 95% CI: 0.5–3.1), diabetes (OR: 0.6, 95% CI: 0.3–1.10) or heart disease (OR: 2.0, 95% CI: 0.4–10).

Conclusions

We observed moderate prevalence of S. mansoni infection among adults in the study per WHO classification of endemicity. This is within the range observed in children in Mangochi from 10 to 56.7%.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41182-022-00450-3.

Prevalence of Schistosoma mono- and co-infections with multiple common parasites and associated risk factors and morbidity profile among adults in the Taabo health and demographic surveillance system, South-Central Côte d'Ivoire

Background

Schistosomiasis remains an important public health problem, also among adults, and infected individuals not treated serve as a reservoir for continued transmission. Despite this fact, evidence on the epidemiology of schistosomiasis in adults in Côte d’Ivoire is scanty. This study aimed to determine the prevalence and risk factors of Schistosoma infection and co-infection with other helminth species and Plasmodium among adults in the Taabo region in the south-central part of Côte d’Ivoire.

Methods

A cross-sectional survey was carried out in April and May 2017 in the frame of the “Côte d’Ivoire Dual Burden of Disease Study” (CoDuBu). A total of 901 randomly selected individuals, aged 18–90 years, provided blood, stool and urine samples for the diagnosis of malaria and helminth infections. Stool samples were subjected to the Kato-Katz technique for detection of Schistosoma mansoni and soil-transmitted helminth eggs, while urine samples were examined for eggs of Schistosoma haematobium and circulating cathodic antigen of S. mansoni. Risk factors and morbidity profiles were assessed using health examination and questionnaires. Multinomial logistic regressions were employed to identify risk factors and morbidity patterns associated with S. mansoni mono- and co-infections.

Results

The prevalence of S. mansoni and S. haematobium was 23.2% and 1.0%, respectively. Most S. mansoni were mono-infections (81.3%). Independent determinants of S. mansoni infection were young age, low socioeconomic status (mono- and co-infection) and poor hygiene practices (co-infection) (P < 0.05). S. mansoni infection was independently associated with higher pain and symptom scores (mono-infection), poor self-rated health and low healthcare use (co-infection) (P < 0.05).

Conclusions

This study showed that adults represent a substantial reservoir of S. mansoni. To sustain schistosomiasis control and improve people’s wellbeing, it is important to expand preventive chemotherapy from school-aged children to adults, coupled with hygiene and health education.

High schistosomiasis-related mortality in Northeast Brazil: trends and spatial patterns

Background:

We analyzed the trends and spatial patterns of schistosomiasis-related mortality in Northeast Brazil in 2000-2019.

Methods:

A mixed population-based ecological study was conducted, using information on the underlying or associated causes of death. We used Joinpoint regression analysis to calculate the trends. The spatial analysis included rates, spatial moving averages, and standardized mortality rates. The spatial dependence analysis was based on Getis-Ord's G and Gi* indices (Gi star) and local Moran’s index to check for autocorrelation.

Results:

A total of 5,814,268 deaths were recorded, of which 9,276 (0.16%) were schistosomiasis-related; 51.0% (n=4,732, adjusted rate 0.90/100,000 inhabitants [95% confidence interval (CI) 0.88-0.93]) were males; 40.0% (n=3,715, adjusted rate 7.40/100.000 inhabitants [95%CI: 7.16-7.64]) were ≥70 years old; 54.8% (n=5,087, crude rate 0.80/100,000 inhabitants) were of mixed/Pardo-Brazilian ethnicity; and 77.9% (n=7,229, adjusted rate 0.86/100,000 inhabitants [95%CI: 0.84-0.88]) lived outside state capitals. The highest proportion of deaths was in the state of Pernambuco (53.9%, n=4,996, adjusted rate 2.72/100,000 inhabitants [95%CI: 2.64-2.79]). Increasing mortality rate was verified in the state of Sergipe. On the coast of the state of Rio Grande do Norte and Bahia, there was spatial dependence of spatio-temporal risk patterns with clusters. Throughout the study period, we found positive spatial autocorrelation and cluster formation.

Conclusions:

In Northeast Brazil, schistosomiasis persists with a high mortality rate, especially in the coastal region, with heterogeneous spatial and temporal patterns. To eliminate schistosomiasis by 2030, it is necessary to strengthen the financing and management of the unified health system (SUS).

Why do few drug delivery systems to combat neglected tropical diseases reach the market? An analysis from the technology's stages

INTRODUCTION

Many drugs used to combat schistosomiasis, Chagas disease, and leishmaniasis (SCL) have clinical limitations such as: high toxicity to the liver, kidneys and spleen; reproductive, gastrointestinal, and heart disorders; teratogenicity. In this sense, drug delivery systems (DDSs) have been described in the literature as a viable option for overcoming the limitations of these drugs. An analysis of the level of development (TRL) of patents can help in determine the steps that must be taken for promising technologies to reach the market.

AREAS COVERED

This study aimed to analyze the stage of development of DDSs for the treatment of SCL described in patents. In addition, we try to understand the main reasons why many DDSs do not reach the market. In this study, we examined DDSs for drugs indicated by WHO and treatment of SCL, by performing a search for patents.

EXPERT OPINION

In this present work we provide arguments that support the hypothesis that there is a lack of integration between academia and industry to finance and continue research, especially the development of clinical studies. We cite the translational research consortia as the potential alternative for developing DDSs to combat NTDs.

Persistent Colonic Schistosomiasis among Symptomatic Rural Inhabitants in the Egyptian Nile Delta

BACKGROUND AND AIMS

Human schistosomiasis is one of the most important and unfortunately neglected tropical diseases. The aim of the current study was to investigate the prevalence and characteristics of colonic schistosomiasis among symptomatic rural inhabitants of the Middle Northern region of the Egyptian Nile delta.

PATIENTS AND METHODS

This study recruited 193 inhabitants of the rural community in the Egyptian Nile Delta referred for colonoscopy because of variable symptoms. After giving written informed consent, they were exposed to thorough history, clinical examination, stool analysis, abdominal ultrasonography, and pan-colonoscopy with biopsies.

RESULTS

Twenty-four cases out of the 193 patients had confirmed active schistosomiasis with a prevalence rate of 12.4%. Bleeding with stool was the predominant manifestation of active Schistosoma infection among the cases either alone or in combination with abdominal pain. On clinical examination, most patients (n=17; 70.8%) did not have organomegaly, and 25% had clinically palpable splenomegaly as far as 75% of them had sonographically detected hepatic periportal fibrosis. Also, 66.6% of patients have significant endoscopic lesions (polyps, ulcers, mass-like lesions), and 16.6% of them had colonic affection beyond the recto-sigmoid region.

CONCLUSION

Colonic schistosomiasis is still prevalent among the Egyptian Nile Delta's symptomatic rural inhabitants at a rate of 12.4%. Of them, 66.6% had significant endoscopic colorectal lesions. This persistent transmission of schistosomiasis in the Egyptian Nile Delta's rural community sounds the alarm for continuing governmental efforts and plans to screen the high-risk groups. The prevalence rate reported in the current study is lower than the actual prevalence rate of schistosomiasis due to focusing only on a subgroup of individuals.

Hepatosplenic schistosomiasis in Zambian adults is characterized by increased liver stiffness: A nested case-control study

Cirrhosis commonly complicates portal hypertension worldwide but in Zambia hepatosplenic schistosomiasis (HSS) dominates as the cause of portal hypertension. We need easier and non-invasive ways to assess HSS. Transient elastography (TE), a measure of liver stiffness can diagnose liver cirrhosis. TE remains unexplored in HSS patients, who generally have normal liver parenchyma. We aimed to explore liver stiffness in HSS. This nested case control study was conducted at the University Teaching Hospital, Lusaka, Zambia between January 2015 and January 2016. We enrolled 48 adults with HSS and 22 healthy controls. We assessed liver stiffness using TE while plasma hyaluronan was used to assess liver fibrosis. Plasma tumor necrosis factor receptor 1 (TNFR1) and soluble cluster of differentiation 14 (sCD14) were used to assess inflammation. The median (interquartile range) liver stiffness was higher in patients, 9.5 kPa (7.8, 12.8) than in controls, 4.7 kPa (4.0, 5.4), P < 0.0001. We noted linear correlations of hyaluronan and TNFR1 with the liver stiffness, P = 0.0307 and P = 0.0003 respectively. HSS patients seem to have higher liver stiffness than healthy controls. TE may be useful in identifying fibrosis in HSS. The positive correlations of inflammatory markers with TE suggest that HSS has both periportal and parenchymal pathophysiology.

Screening a repurposing library, the Medicines for Malaria Venture Stasis Box, against Schistosoma mansoni

Background

The development of new treatments against schistosomiasis is imperative but lacks commercial interest. Drug repurposing represents a suitable strategy to identify potential treatments, which have already unblocked several essential steps along the drug development path, hence reducing costs and timelines. Promoting this approach, the Medicines for Malaria Venture (MMV) recently distributed a drug repurposing library of 400 advanced lead candidates (Stasis Box).

Methods

All 400 compounds were initially tested in vitro against the larval stage of Schistosoma mansoni at 10 μM. Hits progressed to screening on adult worms and were further characterised for IC_50, cytotoxicity and selectivity. Ten lead compounds were tested in mice harbouring a chronic S. mansoni infection.

Results

Eleven of the 37 compounds active on the larval stage were also highly active on adult worms in vitro (IC₅₀ = 2.0–7.5 μM). IC₅₀ values on adult S. mansoni decreased substantially in the presence of albumin (7.5–123.5 μM). Toxicity to L6 and MRC cells was moderate. A moderate worm burden reduction of 51.6% was observed for MMV690534, while the other 9 compounds showed low activity. None of the in vivo results were statistically significant (P > 0.05).

Conclusions

Phenotypic screening of advanced lead compounds is a simple and resource-low method to identify novel anthelminthics. None of the promising hits of the Stasis Box identified in vitro against S. mansoni yielded acceptable worm burden reductions in vivo, which might be due to the high plasma protein binding. Since the in vitro hits interfere with different drug targets, they might provide a starting point for target based screening and structure-activity relationship studies.

Ratio of platelet count/spleen diameter predicted the presence of esophageal varices in patients with schistosomiasis liver cirrhosis

AIM

To examine the platelet count (PC)/spleen diameter (SD) ratio in predicting the presence of esophageal varices (EV) in patients with schistosomiasis liver cirrhosis.

MATERIALS AND METHODS

A total of 95 consecutive patients with EV induced by schistosomiasis liver cirrhosis were enrolled in this trial. A total of 141 schistosomiasis liver cirrhosis patients without EV were enrolled as controls. All patients were diagnosed by endoscopy. Demographic, laboratory, and Doppler ultrasound parameters were collected and analyzed. Binary logistic regression analysis was carried out to identify independent risk factors associated with EV occurrence. Receiver operating curves were generated to obtain the PC/SD ratio cutoff values for the optimal sensitivity and specificity with respect to EV.

RESULTS

The accuracy was increased in diagnosing for EV using the ratio of PC/SD compared with the SD alone [area under the curve: 0.891 95% confidence interval (CI): 0.844-0.928 vs. 0.764 95% CI: 0.705-0.817; P<0.01]. The optimal cutoff value was 1004, with a 77.1% (95% CI: 67.9-84.8%) positive-predictive value and an 89.3% (95% CI: 82.7-94.0%) negative-predictive value. Using a cutoff of 1004, it was determined that 117/141 (83.0%) patients without EV could avoid undergoing unnecessary endoscopy, whereas 14/95 (14.7%) patients with EV would be misdiagnosed. In contrast, when the ratio was set at 909, the positive-predictive and negative-predictive values were 79.5% (95% CI: 69.5-87.4%) and 83.1% (95% CI: 76.1-88.8%), respectively. A ratio of 909 would accurately predict the absence of EV in 123/141 (87.2%) patients; however, 24/95 (25.3%) patients with EV would miss the necessary screening endoscopy.

CONCLUSION

The ratio of PC/SD was a useful marker in predicting the presence of EV in patients with schistosomiasis liver cirrhosis.

Trends in schistosomiasis-related mortality in Brazil, 2000-2011

Schistosomiasis is an important public health problem, with high morbidity and mortality in endemic countries. We analysed the epidemiological characteristics and time trends of schistosomiasis-related mortality in Brazil. We performed a nationwide study based on official mortality data obtained from the Brazilian Mortality Information System. We included all deaths in Brazil between 2000 and 2011, in which schistosomiasis was mentioned on the death certificate as an underlying or associated cause of death (multiple causes of death). We calculated crude and age-adjusted mortality rates (per 100,000 inhabitants), and proportional mortality rates. Trends over time were assessed using joinpoint regression models. Over the 12-year study period, 12,491,280 deaths were recorded in Brazil. Schistosomiasis was mentioned in 8,756 deaths, including in 6,319 (72.2%) as an underlying cause and in 2,437 (27.8%) as an associated cause. The average annual age-adjusted mortality rate was 0.49 deaths/100,000 inhabitants (95% confidence interval: 0.46-0.52) and proportional mortality rate was 0.070% (95% confidence interval: 0.069-0.072). Males (0.53 deaths/100,000 inhabitants), those aged ⩾70years (3.41 deaths/100,000 inhabitants), those of brown race/colour (0.44 deaths/100,000 inhabitants), and residents in the Northeast region of Brazil (1.19 deaths/100,000 inhabitants) had the highest schistosomiasis-related death rates. Age-adjusted mortality rates showed a significant decrease at a national level (Annual Percent Change: -2.8%; 95% confidence interval: -4.2 to -2.4) during the studied period. We observed decreasing mortality rates in the Northeast (Annual Percent Change: -2.5%; 95% confidence interval: -4.2 to -0.8), Southeast (Annual Percent Change: -2.2%; 95% confidence interval: -3.6 to -0.9), and Central-West (Annual Percent Change: -7.9%; 95% confidence interval: -11.3 to -4.3) regions, while the rates remained stable in the North and South regions. Despite the reduced mortality, schistosomiasis is still a neglected cause of death in Brazil, with considerable regional differences. Sustainable control measures should focus on increased coverage, and intensified and tailored control measures, to prevent the occurrence of severe forms of schistosomiasis and associated deaths.

Clinical and epidemiological aspects of hepatocellular carcinoma in Brazil

The global hepatocellular carcinoma (HCC) incidence is widely variable, depending on geographic region and the prevalence of major risk factors. In Brazil, two large multicentre retrospective studies were performed to investigate clinical and epidemiological aspects of HCC. In the first study, performed in 1997, HCC was found in cirrhotic livers in 71% of cases. Chronic alcoholism was present in 36% of cases, chronic hepatitis B in 35% and hepatitis C in 25%. In a 2010 survey, cirrhosis was present in 98% of cases and HCV was the main aetiology (54%). Differences in HBV prevalence were found among regions. Selection of HCC treatment depends on tumour burden, liver function and performance status. Liver transplantation (LT) is the best available curative treatment for HCC in its early stage and with compromised liver function. After modifications in priority policy, the number of patients with early HCC submitted for LT has increased in the past 5 years in Brazil. Chemoembolization is the most common initial HCC therapy in early and intermediate stages of HCC in Brazil.

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.

Use of the platelet count/spleen diameter ratio for the noninvasive diagnosis of esophageal varices in patients with schistosomiasis

BACKGROUND/AIM

In patients with liver cirrhosis, the platelet count/spleen diameter ratio has been validated as a parameter for the noninvasive diagnosis of esophageal varices. Schistosoma infection is a frequent cause of portal hypertension in Middle Eastern countries, and is associated with the development of esophageal varices. In this study we aimed to evaluate the platelet count/spleen diameter ratio as a noninvasive tool for the prediction of the presence of esophageal varices in patients with schistosoma-related chronic liver disease.

PATIENTS AND METHODS

Forty-three patients with hepatosplenic schistosomiasis underwent upper digestive endoscopy to check for the presence of esophageal varices. Furthermore, all patients underwent abdominal ultrasonography, and maximum spleen diameter (in mm) was measured. The platelet count/spleen diameter ratio was calculated in all patients.

RESULTS

Esophageal varices were found in 31 patients (72%). Age and gender were not significantly different between patients with and without varices. In patients with varices, median platelet count (82,000/μL versus 172,000/μL, P < 0.0001) and platelet count/spleen diameter ratio (571 versus 1651, P < 0.0001) were significantly lower, while spleen diameter (147 mm versus 109 mm, P = 0.0006) was significantly larger. In multivariate analysis, the platelet count/spleen diameter ratio was the only parameter independently associated with the presence of varices (P < 0.0001).

CONCLUSIONS

In this study we have validated the use of the platelet count/spleen diameter ratio for the noninvasive diagnosis of esophageal varices in patients with portal hypertension caused by schistosoma infection. In these patients, the platelet count/spleen diameter ratio might be used to allow better rationalization of medical resources and use of endoscopy.

Relationship between intestinal parasitic infection in children and soil contamination in an urban slum

PURPOSE

Urban slums are well known for their high infant mortality and morbidity rates, and parasitic infections seem to be a common problem among these children. The aim of the present study was to determine protozoa and nematodes prevalence among children of a selected community located in São Paulo, Brazil, and access the relation between soil and children infection.

METHODS

Soil contamination samples from 15 strategic locations in the slum area as well as stool samples (examined for protozoa and nematodes through five different methods) from 120 children aged 2-14 years (49% M: 51% F, mean +/- SD = 7.9 +/- 3.8 years) were assessed in a cross-sectional study. Children's domicile locations were determined, and a comparative analysis was undertaken to correlate children and soil infection.

RESULTS

Overall infection rate was 30.8% (n = 37), without difference between genders. The most frequent intestinal protozoa were Endolimax nana (20.8%), Entamoeba coli (15.8%) and Giardia lamblia (16.7%). Frequencies of Ascaris lumbricoides and Enterobius vermicularis in stool samples were 2.5 and 1.7%, respectively. No cases of hookworms, Schistosoma mansoni or Tricuris trichiura were identified. Polyparasitism occurred in 10.8% of the children, while 69.2% were free of parasitic infections. Out of the 15 soil samples analyzed, Ascaris sp. eggs were found in 20% and hookworm eggs in 6.7%.

CONCLUSION

Helminth infection is not as prevalent as previously reported in urban slums in São Paulo, neither as clinical disease nor in soil samples. Protozoa intestinal infection, however, is still frequent in some marginalized populations in São Paulo. Improvement in living standards, mostly sanitation might decrease the prevalence of these diseases.

Cytokines, chemokine receptors, CD4+CD25HIGH+ T-cells and clinical forms of human schistosomiasis

Previous studies have demonstrated that distinct immune response profiles can be correlated with the development/maintenance of different clinical forms of human schistosomiasis. We have previously shown that individuals with the more severe clinical forms of the disease such as those presenting different levels of fibrosis or with the hepatosplenic (HS) clinical form of the disease show significantly different immune response when compared with those with the intestinal clinical form (INT). To better understand the immune mechanisms associated with the clinical form of the schistosomiasis, in this study, we present the results of the evaluation, at a single cell level, of the cytokine patterns as well as the chemokine receptors expression by T-cell subsets after in vitro short-term stimulation with soluble egg antigens as well as the ex vivo frequency analysis of putative regulatory CD4+CD25HIGH+ T-cell subset in the peripheral blood mononuclear cells. We observed an increase on IL-4+, IL-5+ and IL-10+ cells both in the CD4+ and CD8+ lymphocytes in INT and a significant decrease on the number of IL-4+, IL-5+ and IL-10+ T-lymphocytes for HS. However, patients with detectable fibrosis presented decrease on IL-10+ (both CD4+ and CD8+ lymphocytes) and basal levels of IL-4 and IL-5. These data suggested that although INT group is under the influence of an effective immunoregulated immune response, mainly due to the high percentage of IL-10+ cells, it presents a mixed type (Type1/Type-2) immune profile. Moreover, the chemokine receptors expression demonstrated that CXCR3 and CXCR4 by CD4+ T-cells in INT may dictate the selective profile of IL-10 associated with the immunomodulatory events in human schistosomiasis. Additionally, the ex vivo analysis also suggests that higher levels of CD4+CD25HIGH+ T-cells may play a role in controlling morbidity in chronic human schistosomiasis. Taken together, these data suggest a major role of IL-10-producing CXCR4+ CD4+ T-cell subset for the asymptomatic outcome of the disease.

Decrease of type IV collagen and TIMP-1 serum levels after splenectomy in patients with schistosomiasis mansoni

The role of the spleen in the process of liver fibrosis in schistosomiasis still needs clarification. The aim of this study was to assess the effect of splenectomy on serum levels of two markers of fibrosis, type IV collagen and TIMP-1, in patients with schistosomiasis mansoni. Twenty-four patients with hepatosplenic schistosomiasis mansoni participated in the study. Type IV collagen and TIMP-1 serum levels were measured preoperatively, and after 2 (POD-1) and 60 days (POD-2) of spleen removal. Before splenectomy, both type IV collagen and TIMP-1 serum levels were elevated in the majority of patients. After splenectomy, the levels of type IV collagen showed a significant decrease in relation to the preoperative values both in POD-1 (median pre-splenectomy: 143.7 ng/ml versus 77.01 ng/ml; p=0.04) and POD-2 (103.3 ng/ml; p=0.015). Serum levels of TIMP-1 also showed a significant decrease in relation to the preoperative values both in POD-1 (pre-splenectomy: 585.9 ng/ml versus 196.4 ng/ml; p=0.008) and POD-2 (97.4 ng/ml; p<0.001). There was no difference between POD-1 and POD-2 values for each serum marker. In conclusion, splenectomy in schistosomotic patients was associated with a decrease in serum markers of fibrosis levels, which persisted for at least 60 days. These results suggest that the spleen may play a role in the extra cellular matrix production, and therefore may contribute to liver fibrosis in schistosomiasis mansoni.