Schistosoma mansoni infection in a recently exposed community in Senegal: lack of correlation between liver morphology in ultrasound and connective tissue metabolites in serum

The role of point-of-care ultrasound in the assessment of schistosomiasis-induced liver fibrosis: A systematic scoping review

BACKGROUND

Abdominal ultrasound imaging is an important method for hepatic schistosomiasis diagnosis and staging. Several ultrasound staging systems have been proposed, each attempting to standardise schistosomal periportal fibrosis (PPF) diagnosis. This review aims to establish the role of ultrasound in the diagnosis and staging of schistosomal PPF, and to map the evolution of ultrasound staging systems over time, focusing on internal validation and external reproducibility.

METHODS

A systematic search was undertaken on 21st December 2022 considering the following databases: PubMed/MEDLINE (1946-present), Embase (1974-present), Global Health (1973-present), Global Index Medicus (1901-present), and Web of Science Core Collection-Science Citation Index Expanded (1900-present) and the Cochrane Central Register of Controlled Trials (1996-present). Case reports, systematic reviews and meta-analyses, and studies exclusively using transient or shear-wave elastography were excluded. Variables extracted included study design, study population, schistosomal PPF characteristics, and diagnostic methods. The PRISMA-ScR (2018) guidelines were followed to inform the structure of the scoping analysis.

RESULTS

The initial search yielded 573 unique articles, of which 168 were removed after screening titles and abstracts, 43 were not retrieved due to full texts not being available online or through inter-library loans, and 170 were excluded during full text review. There were 192 remaining studies eligible for extraction. Of the extracted studies, 61.8% (76/123) of studies that reported study year were conducted after the year 2000. Over half of all extracted studies (59.4%; 114/192) were conducted in Brazil (26.0%; 50/192), China (18.8%; 36/192) or Egypt (14.6%; 28/192). For the species of schistosome considered, 77.6% (149/192) of studies considered S. mansoni and 21.4% (41/192) of studies considered S. japonicum. The ultrasound staging systems used took on three forms: measurement-based, feature-based and image pattern-based. The Niamey protocol, a measurement and image pattern-based system, was the most used among the staging systems (32.8%; 63/192), despite being the most recently proposed in 1996. The second most used was the Cairo protocol (20.8%; 40/192). Of the studies using the Niamey protocol, 77.8% (49/63) only used the image patterns element. Where ultrasound technology was specified, studies after 2000 were more likely to use convex transducers (43.4%; 33/76) than studies conducted before 2000 (32.7%; 16/49). Reporting on ultrasound-based hepatic diagnoses and their association with clinical severity was poor. Just over half of studies (56.2%; 108/192) reported the personnel acquiring the ultrasound images. A small number (9.4%; 18/192) of studies detailed their methods of image quality assurance, and 13.0% (25/192) referenced, discussed or quantified the inter- or intra-observer variation of the staging system that was used.

CONCLUSIONS

The exclusive use of the image patterns in many studies despite lack of specific acquisition guidance, the increasing number of studies over time that conduct ultrasound staging of schistosomal PPF, and the advances in ultrasound technology used since 2000 all indicate a need to consider an update to the Niamey protocol. The protocol update should simplify and prioritise what is to be assessed, advise on who is to conduct the ultrasound examination, and procedures for improved standardisation and external reproducibility.

Clinico-epidemiology, malacology and community awareness of Schistosoma mansoni in Haradenaba and Dertoramis kebeles in Bedeno district, eastern Ethiopia

Background:

Schistosoma mansoni is a major public health problem. Different studies reported unidentified sites in Ethiopia with variable prevalence and intensity, but there is no report from this study area.

Objective:

To assess the clinico-epidemiology, malacology, risk factors, and community awareness of S. mansoni in Haradenaba and Dertoramis kebeles in the Bedeno district, eastern Ethiopia.

Methods:

A cross-sectional study was conducted among 1011 study participants in 413 systematically selected households from Haradenaba and Dertoramis kebeles from 30 June 2016 to 30 July 2017. Data were collected by using pretested, structured questionnaires, clinical examinations, and stool examinations. Stool samples were processed by the Kato-Katz method and examined microscopically. Snails were collected by scooping from water contact points. Data were analyzed using SPSS, version 16 statistical software.

Result:

The overall prevalence of S. mansoni was 35.7%. Heavy-intensity infection was detected in 8.9% of the study participants. Results included: participants who were unaware about the possible source of infection (adjusted odds ratio: 2.95; 95% confidence interval: 1.25, 7.95), modes of transmission (adjusted odds ratio: 5.51; 95% confidence interval: 3.52, 12.51), prevention (adjusted odds ratio: 4.01; 95% confidence interval: 2.00, 8.75) about schistosomiasis/bilharziasis were more likely infected with S. mansoni than those who were aware. Participants who swim or bathe in the river were more likely infected with S. mansoni than those who do not (adjusted odds ratio: 6.41; 95% confidence interval: 3.15, 11.25). Biomphalaria pfeifferi snails were collected from all water bodies in Haradenaba and Dertoramis, but they did not shed schistosome cercaria in the laboratory.

Conclusion:

S. mansoni infection is found in high magnitude in these study areas, despite not being previously reported. A majority of the study participants had low awareness about the source of infection, mode of transmission, and prevention methods of schistosomiasis. Efforts should be made to improve community awareness about transmission and prevention of schistosomiasis.

New index for the diagnosis of liver fibrosis in Schistosomiasis mansoni

BACKGROUND

- Periportal fibrosis is the major pathological consequence of the Schistosoma mansoni infection.

OBJECTIVE

- To evaluate the accuracy of serum markers and to construct an index to assess fibrosis.

METHODS

- Patients (n=116) with schistosomiasis were evaluated by ultrasound scan and measurements of serum levels of aminotransferases, γ-glutamyl transferase, alkaline phosphatase, hyaluronic acid, cytokines and platelets. Ultrasound images were used to evaluate the fibrosis using Niamey's classification and identified 19 patients without periportal fibrosis (patterns A and B), 48 with mild to moderate fibrosis (C and D) and 49 with advanced fibrosis (E and F).

RESULTS

- Using multivariate analysis, a model was created, which involved alkaline phosphatase and platelets and could separate patients with different patterns of fibrosis. This index showed a better performance in separating patients without fibrosis from with advanced periportal fibrosis. The biological index showed an area under the ROC curve of 1.000. Using values below the lowest or above the highest cut-off point, the presence or absence of advanced fibrosis could be predicted in all patients.

CONCLUSION

- The index constructed can be used to separate patients with different patterns of periportal fibrosis, specially to predict advanced fibrosis in schistosomiasis patients.

Ultrasonography of gallbladder abnormalities due to schistosomiasis

After malaria, schistosomiasis remains the most important tropical parasitic disease in large parts of the world. Schistosomiasis has recently re-emerged in Southern Europe. Intestinal schistosomiasis is caused by most Schistosoma (S.) spp. pathogenic to humans and leads to chronic inflammation and fibrosis of the colon as well as to liver fibrosis. Gallbladder abnormalities usually occur in patients with advanced hepatic portal fibrosis due to Schistosoma mansoni infection. Occasionally, gallbladder abnormalities have been seen also in children and occurring without associated overt liver abnormalities.The specific S. mansoni-induced gallbladder abnormalities detectable by ultrasound include typical hyperechogenic wall thickening with external gallbladder wall protuberances. The luminal wall surface is smooth. The condition is usually clinically silent although some cases of symptomatic cholecystitis have been described. The ultrasonographic Murphy response is negative. Gallbladder contractility is impaired but sludge and calculi occur rarely. Contrary to other trematodes such as liver flukes, S. mansoni does not obstruct the biliary tract. Advanced gallbladder fibrosis is unlikely to reverse after therapy.

The chronic enteropathogenic disease schistosomiasis

Schistosomiasis is a chronic enteropathogenic disease caused by blood flukes of the genus Schistosoma. The disease afflicts approximately 240 million individuals globally, causing approximately 70 million disability-adjusted life years lost. Chronic infections with morbidity and mortality occur as a result of granuloma formation in the intestine, liver, or in the case of Schistosoma haematobium, the bladder. Various methods are utilized to diagnose and evaluate liver fibrosis due to schistosomiasis. Liver biopsy is still considered the gold standard, but it is invasive. Diagnostic imaging has proven to be an invaluable method in assessing hepatic morbidity in the hospital setting, but has practical limitations in the field. The potential of non-invasive biological markers, serum antibodies, cytokines, and circulating host microRNAs to diagnose hepatic fibrosis is presently undergoing evaluation. This review provides an update on the recent advances made with respect to gastrointestinal disease associated with chronic schistosomiasis.

Sonographic response in the liver and urinary bladder of children 14 months after treatment for schistosomiasis

After praziquantel treatment for schistosomiasis, parasitological cure rates of 60%–90% are usual. Does this response to treatment correlate with the improvement in liver and bladder changes seen on ultrasound in children? This study shows that ultrasound is an effective way to evaluate liver and bladder changes caused by schistosomiasis infection in children and to assess treatment effects after mass treatment programmes.

Ultrasound versus biological markers in the evaluation of periportal fibrosis in human Schistosoma mansoni

In this paper, the authors review the literature and share their experience of the principal biological markers of fibrosis for the evaluation of periportal fibrosis (PPF) caused by mansoni schistosomiasis. These biological markers are compared to diagnostic ultrasound (US) scans as means of grading PPF. We also review procollagen type I and III, collagen type IV, laminin, hyaluronic acid (HA), immunoglobulin G, platelets, aspartate aminotransferase to platelet ratio index (APRI) and gamma-glutamyl transpeptidase as markers of the disease. Although there are several good markers for evaluating PPF and portal hypertension, such as HA, platelets or APRI, none can yet replace US. These markers may, however, be used to identify patients at greater risk of developing advanced disease in endemic areas and determine who will need further care and US studies.

Schistosomiasis mansoni: ultrasound-evaluated hepatic fibrosis and serum concentrations of hyaluronic acid

Schistosomiasis mansoni is a fibrogenic liver disease that constitutes a major health problem in north-eastern Brazil. Although one common manifestation of the disease, periportal fibrosis (PPF), can be assessed by ultrasonography by well-trained physicians, the necessary equipment and personnel are not always readily available. Serum markers, including hyaluronic acid (HA), have been used as alternative means of measuring fibrosis. Recently serum concentrations of HA have been evaluated in 77 Brazilians (61 cases of schistosomiasis mansoni and 16 healthy controls) and compared against the ultrasound-evaluated PPF in the same subjects. The HA was measured using a non-competitive fluorescence-based assay, while the PPF was explored using a portable ultrasound scanner (SSD-500; Aloka, Tokyo) and graded, as patterns A-F, according to the World Health Organization's 'Niamey protocol'. In general, the serum concentrations of HA were found to be positively correlated with the severity of the PPF. The mean concentration of HA in the sera of the 16 controls was significantly lower than that recorded in the schistosomiasis cases who showed PPF of patterns D or E (P<0·001 for each). The cases who showed pattern-C PPF also had significantly less HA in their sera than the cases with PPF of patterns D or E (P<0·001 for each), and the cases with pattern-D fibrosis had significantly lower HA concentrations in their sera than the cases with PPF of pattern E (P<0·001). In an analysis based on a receiver-operating-characteristic (ROC) curve, an HA concentration of 20·2 μg/litre of serum was identified as a threshold that could be used to distinguish moderate cases of PPF (i.e. patterns C or D) from the more advanced cases (i.e. patterns E or F), with a sensitivity of 60% and specificity of 65%. In conclusion, it appears that serum concentrations of hyaluronic acid could be used as markers for periportal fibrosis in patients with schistosomiasis mansoni.

Familial aggregation of human helminth infection in the Poyang lake area of China with a focus on genetic susceptibility to schistosomiasis japonica and associated markers of disease

Human helminthiases are common in China, especially in rural areas where sanitation conditions are poor. Soil-transmitted helminths (STHs) are predominantly found in the southern provinces. Schistosoma japonicum is also endemic to southern China. Here we review the prevalence of helminth infections and polyparasitism in China, and discuss the interactions between helminth parasites in the co-infected host. It is clear that STHs are more prevalent in rural China than previously suggested emphasizing the need for systematic control of STHs. Further, the need for improved sanitation and hygiene conditions to prevent parasite transmission is highlighted. We provide supporting evidence for human genetic susceptibility to both single helminth infection and polyparasitism, and suggest that susceptibility to helminths infections may not be independent of one or the other. We demonstrate an association between single nucleotide polymorphism (SNP) variants in IL-5 and symptomatic S. japonicum infection and discuss the potential role of IL-5 in other helminth infections. Fundamental to disease and morbidity control is adequate and effective diagnosis and surveillance of disease. We discuss the role of sICAM-1 and TNFR-I and -II as candidate markers for schistosome-induced hepatomegaly and fibrosis, and their potential for assessing disease stage and progression in schistosomiasis.

sTNFR-II and sICAM-1 are associated with acute disease and hepatic inflammation in schistosomiasis japonica

Soluble intracellular adhesive molecule 1 (sICAM-1) and tumour necrosis factor receptors I (TNFR-1) and II (TNFR-II) have been shown to be associated with numerous liver disorders. Shedding of these membrane proteins can be triggered by the Th1 cytokines, TNF-alpha and IFN-gamma, which are associated with susceptibility or resistance to hepatic schistosomiasis, respectively. Further, TNF-alpha receptors and sICAM-1 have been implicated in periportal fibrosis in advanced human schistosomiasis mansoni and correlate with schistosome granuloma formation in the murine model. We measured serum levels of sICAM-1, TNFR-I and TNFR-II in Chinese patients with different clinically defined stages of schistosomiasis japonica and controls; these included 35 patients with acute schistosomiasis, 45 patients with chronic schistosome infections, 34 advanced patients with evidence of severe morbidity and 20 patients with no known history of exposure to infection. Markedly elevated levels of soluble TNFRs (sTNFRs) and sICAM-1 were observed in the acute and advanced patients compared with the chronic and control groups. Mean sTNFR-II levels were significantly higher in acute patients compared with advanced (P < 0.00001) and chronic patients (P < 0.00001) and showed the strongest association of the markers with acute disease (odds ratio (OR) = 1.099). sTNFR-II and sICAM-1 levels both correlated with infection intensity and there were significant positive correlations observed between eosinophil count and infection intensity (P = 0.0072) and sICAM-1 (P = 0.0014). Although there were significantly higher levels of antigen-specific IgG4 and total IgG in infected individuals compared with controls, none correlated with infection intensity. Further, no differences in IgG4 and total IgG levels were observed between the acute and chronic groups. The results suggest sTNFRs and sICAM-1 are associated with liver inflammation and disease progression. Measurement of sTNFR-II and sICAM-1 levels in serum could serve as additional markers for the diagnosis of acute stage disease and the monitoring of hepatic inflammation in human schistosomiasis japonica.

Clinical and ultrasound findings before and after praziquantel treatment among Venezuelan schistosomiasis patients

Abdominal ultrasound can be a useful tool for diagnosing periportal fibrosis related to Schistosoma mansoni infection, and also for planning and monitoring the evolution of hepatic morbidity following control measures. We evaluated the standardized ultrasound methodology proposed by the World Health Organization for detecting periportal fibrosis and portal hypertension, among patients from an endemic area in Venezuela, and the impact of praziquantel treatment 3-5 years later. After chemotherapy, complete reversal of periportal lesions was observed in 28.2% of the cases and progression of the disease in 5.1%. Improvement in the hepatic disease started with a reduction in the periportal thickening followed by a decrease in the size of the left hepatic lobe, spleen and mesenteric and spleen veins. Ultrasound confirmed the clinical findings after chemotherapy among the patients with reversal of the disease. However, in patients with more advanced disease, these findings were contradictory. There was no correlation between evolution of the disease seen on ultrasound and age, intensity of infection or serological findings.

Serum laminin assayed by Slot-Blot-ELISA in patients with combined viral hepatitis C and schistosomiasis

OBJECTIVES

Hepatic schistosomiasis and chronic hepatitis C virus (HCV) are the most prevalent agents causing hepatic fibrosis in humans. Laminin (LA) has been related to liver fibrosis and subsequent development of portal hypertension in chronic liver disease. There are no available data describing the pattern of laminin in combined HCV and schistosoma-infected patients, thus the rationale of this study was to assess the serum LA as an index of liver fibrosis in patients with schistosomiasis and/or chronic viral hepatitis C and to evaluate a developed Slot-Blot Enzyme-Linked Immunosorbant Assay (Slot-Blot-ELISA) as a method of estimation.

DESIGNS AND METHODS

This study included four groups: group I included 34 patients with schistosomiasis, group II included 58 patients infected with HCV, group III included 68 patients with combined chronic viral hepatitis C and schistosomiasis and group IV included 50 healthy individuals who served as a control group. Serum LA was measured in the different groups quantitatively by ELISA and semi-quantitatively by Slot-Blot-ELISA.

RESULTS

Significantly higher serum LA concentrations measured by ELISA were found in patients with combined chronic viral hepatitis C and schistosomiasis than in patients with either chronic HCV (P = 0.005) or schistosomiasis (P < 0.001) alone. Serum LA was significantly higher in the patient groups than the control group (P < 0.001). Serum LA concentration was positively correlated with fibrosis grading scores. Semi-quantitative results of serum LA using the developed SB-ELISA were found to have approximately the same power of ELISA results in different groups. The overall sensitivity, specificity, positive predictive value, negative predictive value and efficiency of ELISA for estimation of serum LA were 85.6%, 84.0%, 94.5%, 64.6% and 90%, respectively and for SB-ELISA were 87.5%, 82.0%, 94%, 67.2% and 88%, respectively.

CONCLUSIONS

Serum LA was significantly increased in patients coinfected with HCV and Schistosoma mansoni. The newly developed Slot-Blot-ELISA is a simple, rapid and highly sensitive assay for detection of LA in hepatic fibrosis. Moreover, all steps were performed at room temperature without the need to use expensive equipment, and this may enhance the application of this assay in screening programs. Further study is warranted for confirmation of SB-ELISA reproducibility in a large population.

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

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

[Sonographic evaluation of periportal fibrosis in children living in a Schistosoma mansoni endemic region]

PURPOSE

To assess with ultrasound periportal fibrosis due to chronic Schistosoma mansoni infection in children living in an endemic region. Materials and methods. A total of 441 children underwent two stool examinations and abdominal sonography. Liver echotexture was assessed by two observers and compared to pre-defined image patterns and a fibrosis score was assigned ranging from 0 to 8. Ultrasound features were correlated to age, sex, and parasitologic findings.

RESULTS

Prevalence of Schistosoma mansoni infestation was 63%. Two cases of advanced fibrosis (E pattern or fibrosis score of 6) were observed. Fibrosis correlated with age. No correlation existed between fibrosis and intensity of egg-output. A correlation between the two examinors was noted in 84% of examinations with a kappa coefficient of 0.7.

CONCLUSION

Although severe periportal fibrosis is a rare finding in this endemic region, follow-up sonography must be performed because it is the only non invasive and reliable tool for detection of periportal fibrosis.

Low awareness of intestinal schistosomiasis in northern Senegal after 7 years of health education as part of intense control and research activities

We evaluated the awareness of and knowledge about intestinal schistosomiasis in a highly infected rural community of northern Senegal where a variety of health information and education activities had taken place for 7 years as a component of different research and control programmes. As the infection had been introduced only recently, an initial 'zero' knowledge can be assumed. Most of the health education activities had been performed with adapted messages through local health and community workers. By a questionnaire, 566 individuals were asked simple questions on symptoms, mode of transmission, the sources of information and health-seeking behaviour. About 86% of the respondents stated that they knew what schistosomiasis was, and 92% that in case of illness they would seek treatment at the health centre. However, only half of the people accurately quoted symptoms associated with intestinal schistosomiasis: diarrhoea, abdominal pain and bloody stools. The majority of respondents realized that the disease was somehow linked with water and (lack of) hygiene, but only 44% of respondents reported water contact as the source of infection. Ultimately, only 30% of the respondents gave adequate answers about both symptoms and mode of transmission. We conclude that even intense and long-lasting education efforts for a specific and straightforward problem as schistosomiasis are not enough to have profound impact on the knowledge of rural traditional communities.

The impact of chemotherapy on morbidity due to schistosomiasis

Current knowledge on the impact of chemotherapy on schistosomiasis-related morbidity is still fragmentary. In urinary schistosomiasis, reversal of organ pathology follows cure after 6 months and resurgence takes place after at least another 6 months. Retreatment after less than 1 year is, therefore, unnecessary. Also, intestinal schistosomiasis appears to regress promptly after chemotherapy. For the reversal of hepatic morbidity, more than one chemotherapy round appears necessary at least in foci of intense transmission of schistosomiasis. The earlier chemotherapy is given, the higher the chances of reversal of schistosomal pathology, but pathology may regress to some extent also in adults. The regression and resurgence of periportal fibrosis, as detected by ultrasonography, occurs with a delay of 7 months to more than 2 years after therapy. Retreatment after less than 1 year may not permit full assessment of the impact of the first round on hepatic morbidity. Children and adolescents should be the major target population, taking into account that in many foci, children out-of-school must be covered because they are at the highest risk. Repeated treatment during childhood may prevent the development of urinary tract disease in adulthood. However, no data are available on the prevention of genital pathology. Repeated chemotherapy may have a long term effect on re-infection intensities and the development of severe morbidity, even in foci where control has been interrupted for many years. Severe hepatic fibrosis may be prevented even in foci of intense transmission provided more than two rounds of chemotherapy have been given in childhood and that chemotherapy is available on demand. Chemotherapy has an important impact on child development, physical fitness and working capacity. Its effect on growth and anemia is improved by simultaneous treatment of intestinal parasites and the provision of adequate iron supplementation. The impact of chemotherapy on many of the multifaceted manifestations of schistosomiasis has not been assessed systematically. More data are needed on gallbladder pathology, neuroschistosomiasis, endocrinologic disorders, bladder cancer and co-infections with other pathogens. In areas where control has been achieved, the overall morbidity and mortality has decreased with a delay of many years or even decades.

Schistosomiasis mansoni in low transmission areas: abdominal ultrasound

In endemic areas with low prevalence and low intensity of infection, the diagnosis of hepatic pathology due to the Schistosoma mansoni infection is very difficult. In order to establish the hepatic morbidity, a double-blind study was achieved in Venezuelan endemic areas, with one group of patients with schistosomiasis and the other one of non-infected people, that were evaluated clinically and by abdominal ultrasound using the Cairo classification. Schistosomiasis diagnosis was established based on parasitologic and serological tests. The increase of the hepatic size at midclavicular and midsternal lines (in hepatometry) and the hard liver consistency were the clinical parameters able to differentiate infected persons from non infected ones, as well as the presence of left lobe hepatomegaly detected by abdominal ultrasound. The periportal thickening, especially the mild form, was frequent in all age groups in both infected and uninfected patients. There was not correlation between the intensity of infection and ultrasound under the current circumstances. Our data suggest that in Venezuela, a low endemic area of transmission of schistosomiasis, the hepatic morbidity is mild and uncommon. The Cairo classification seems to overestimate the prevalence of periportal pathology. The specificity of the method must be improved, especially for the recognition of precocious pathology. Other causes of hepatopathies must be investigated.

Serum hyaluronic acid as a comprehensive marker to assess severity of liver disease in schistosomiasis

Schistosomiasis mansoni is a non-cirrhotic fibrogenic disease model. The mild form shows normal liver function with slight or no liver fibrosis whereas in the periportal fibrosis form the manifestations of portal hypertension prevail over hepatocellular failure. We assessed serum hyaluronic acid as a marker of the course of the disease. We studied 24 patients presenting with pure chronic forms of schistosomiasis and seven with cirrhosis. In order to measure serum hyaluronic acid we developed a sandwich fluorescent ELISA-like assay. alpha2-Macroglobulin, prothrombin index, gamma-glutamyltransferase, platelets and ultrasound parameters were also assessed. The 20 micro g/l (ROC plot) hyaluronic acid level differentiated patients with the mild form (with no portal hypertension) from those with the severe form of schistosomiasis with 78% diagnostic efficacy. The 80 micro g/l cut-off value differentiated patients with the severe form of schistosomiasis from the cirrhotic group with similar diagnostic efficacy. alpha2-Macroglobulin provided no distinction between the groups studied. The hyaluronic acid serum concentration correlated positively with the splenic vein diameter (P=0.004) and marginally with alpha2-macroglobulin (P=0.059). Serum hyaluronic acid is a good marker for the initial phase of hepatic fibrosis and it was able to assess severity of liver disease in schistosomiasis.

Evaluation of staff performance and material resources for integrated schistosomiasis control in northern Senegal

BACKGROUND

A project to improve integrated control of schistosomiasis in the primary health care system of northern Senegal was implemented from February 1995 until September 1999, shortly after a Schistosoma mansoni outbreak. The activities included additional training of doctors and nurses in symptom-based treatment and making praziquantel (PZQ) available for an affordable price.

OBJECTIVE

To investigate staff performance and the availability and costs of diagnostic materials and PZQ at the end of this intervention project.

METHODS

We performed structured interviews with staff from 55 health care facilities in five districts.

RESULTS

Respondents from 23 health care facilities reported both S. haematobium and S. mansoni in the coverage area, 32 reported only S. haematobium and three only S. mansoni. The average cost to patients for consultation, diagnosis, treatment and transportation to a referral health care facility was approximately 1.60 Euro. Fifty-seven per cent of the health care facilities with reported S. haematobium in the coverage area treated patients presenting with haematuria on symptoms; 56% of the health care facilities with reported S. mansoni in the coverage area treated patients presenting with blood in stool on symptoms. Thirteen per cent performed a diagnostic test for patients presenting with haematuria and 12% for patients presenting with blood in stool. The remainder, approximately one-third of the health care facilities, referred their patients to another facility for a diagnostic test. Implementation of symptom-based treatment in all health care facilities will reduce the total costs by 0.43 Euro (29%) for patients infected with S. haematobium and 0.78 Euro (46%) for patients infected with S. mansoni. Of the 53 health care facilities with schistosomiasis in their area, 37 had PZQ in stock of which 33 (88%) sold PZQ for the recommended retail price of 0.15 Euro per tablet (or 0.60 Euro per course of four tablets) or lower.

CONCLUSION

Four years after the start of the intervention project, patients presenting with schistosomiasis related symptoms can generally expect proper diagnosis and treatment at all levels of the health care system in Northern Senegal, either at the initial visited health care facility or after referral. However, a further reduction of the total costs of treatment is still possible by a better implementation of symptom-based treatment and further reduction of the costs of PZQ.

Evolution of schistosomiasis-induced pathology after therapy and interruption of exposure to schistosomes: a review of ultrasonographic studies

Ultrasonography (US) is suitable for diagnosing schistosomiasis-related organic pathology and is particularly useful to assess its evolution after therapy and/or interruption of exposure to the Schistosoma parasites. Evolution of pathology after treatment: Regression of hepatic abnormalities in Schistosma mansoni-infected children and adolescents has been observed already from 7 months post-therapy on. This does, however, not occur in all cases: individual differences are great ranging from spontaneous regression of pathology without treatment to persistence of pathology lasting for years after therapy even without re-infection. Intensity and duration of exposure, different parasite strains, patients' age and genetic background all influence the evolution of pathology. In communities at continuous exposure to S. mansoni infection, repeated re-treatment is required to control hepatosplenic morbidity. In Schistosoma japonicum infection, changes around the portal tree may regress, but characteristic diffuse abnormalities described as 'network pattern' abnormalities do not resolve. In Schistosoma haematobium infection bladder abnormalities and urinary tract obstruction frequently resolve after treatment. Clinically relevant pathology may resurge from 1 year after therapy on if exposure continues. Subjects with more advanced pathology before therapy, appear to be at higher risk of pathology re-appearance. Evolution of pathology after interruption of exposure to schistosomiasis: Knowledge on the evolution of pathology induced by S. mansoni is limited to some reports in emigrants and to the experience of ultrasonographists working in areas, where transmission has been partially interrupted. Due to the longevity of the parasite, infection may last for many years. Even after elimination of the parasites severe pathology may persist for long. In S. haematobium infection spontaneous healing after interruption of re-exposure may occur, but cases have been reported where urogenital lesions led to complications many years after exposure. Contrary to hepatosplenic and urinary pathology, knowlegde on the evolution of other organic abnormalities is very limited: studies on the evolution of biliary abnormalities or intestinal pathology have not been published. Genital pathology may be induced by all Schistosoma spp. Post-therapy evolution of genital schistosomiasis is largely ignored. In some European travellers partial regression of prostatic fibrosis has been described. Schistosomal adnexitis leading to infertility and/or ectopic pregnancy has been reported occurring many years after interruption of exposure. Ultrasonography (US) has never been used to study the influence of schistosomiasis on pregnancy. Concluding, current knowlegde on the evolution of pathology after treatment and/or interruption of exposure is still fragmentary. Frequently, fibrosis reverses after therapy, but advanced pathology may persist for long. Therefore, the possibility of severe clinical complications has to be taken into account, even if the infection is inactive since many years. In interventions aimed at controlling schistosomiasis-related morbidity, evolution of pathology must be monitored by US in representative patient cohorts. Further systematic US-studies are needed not only on the evolution of hepatosplenic and urinary pathology but also on that of intestinal, biliary and genital pathology induced by schistosomiasis, as well as on the influence of schistosomiasis on the outcome of pregnancy.

[A case of hepatic Loeffler's syndrome]

INTRODUCTION

During nematode infection transit of the microorganism in the lung may be associated with transient infiltration lesions accompanied by marked eosinophilia. In the invasion stage of the disease maturation and sexual differentiation of schistosomules is restricted to portal vessels. Liver ultrasonography may show concomitant abnormalities.

EXEGESIS

Eosinophilia was diagnosed in a 36-year-old man residing in Central Africa. Clinical examination, chest X-ray and biology were normal. Liver ultrasonography showed numerous hypoechoic lesions, up to 3 cm in diameter. Ultrasonography-directed biopsy demonstrated infiltration of both portal vessels and liver sinusoids, with sometimes microabcesses. No parasite was found in either blood, stool, or rectal biopsy. Immunoelectrophoresis and hemagglutination showed positive bilharziosis serology, whereas serology for other helminthiases was negative. Four months after treatment eosinophilia was still high, liver ultrasonography was normal, and hemagglutination was negative.

CONCLUSION

The transient shistosomules maturation-related liver abnormalities detected by ultrasonography should be differentiated from the laying phase of the disease.

Hyaluronate levels and markers of oxidative stress in the serum of Sudanese subjects at risk of infection with Schistosoma mansoni

We showed previously that infection by Schistosoma mansoni not only triggers the production of reactive oxygen species in mouse liver but also leads to the alteration of antioxidant defences. To determine whether such events occur in humans, we measured the serum markers of oxidative stress, i.e., lipid peroxides and protein carbonyl, as well as hyaluronate levels in subjects in the Managil area of the Sudan. Grades of fibrosis were determined by ultrasonographic examination. Two groups were used as controls, one Sudanese and the other European. We found that Sudanese subjects in the endemic area differed from the control groups, both Sudanese and European, insofar as they had higher levels of the serum metabolites measured. The latter increased with the grade of fibrosis. Moreover, protein carbonyl and hyaluronic acid levels correlated positively with lipid peroxide levels. These findings indicate that oxidative stress might contribute to S. mansoni-associated pathology in man. The serum markers considered in our study, obtained by relatively simple techniques, may provide a useful biochemical index for the identification of almost asymptomatic patients who, however, are at risk of developing severe schistosomiasis.

Diagnostic value of connective tissue metabolites in Schistosoma mansoni related liver disease

Reliable non-invasive markers of hepatosplenic involvement in schistosomiasis are needed for determination of morbidity levels in endemic populations and for diagnosis and follow-up of affected individuals. Serum levels of connective tissue metabolites have been investigated as fibrosis markers in various hepatic disorders, but their accuracy in the detection of hepatosplenic schistosomiasis under endemic conditions has not been fully elucidated. 206 adult inhabitants of a Tanzanian village highly endemic for schistosomiasis mansoni (prevalence 88%) underwent clinical, parasitological and sonographic work-up; sera were tested for aminoterminal procollagen III-peptide (PIIIP), carboxyterminal procollagen IV peptide (NC1) and laminin. Connective tissue marker levels did not correlate with the presence or intensity of infection. NC1 levels were significantly correlated with periportal liver fibrosis (P < 0.001), splenomegaly (P < 0.002), portal vein dilatation (P < 0.004) and the presence of portosystemic collaterals (P < 0.001); for PIIIP and laminin, none of the respective relationships was significant. Due to wide overlap of NC1 levels between individuals with normal sonography findings and those with advanced periportal fibrosis and portal hypertension, the sensitivity and positive predictive value of this markers to detect these individuals were low (< 40%), although specificity and overall accuracy in the given setting were good (80-90%). It is concluded that PIIIP and laminin are not useful as diagnostic serum markers of hepatosplenic schistosomiasis at the community level; NC1 was significantly related to various indices of hepatosplenic involvement, but its low sensitivity precludes its use as a screening tool under endemic conditions.