Ultrasonographical investigation of periportal fibrosis in children with Schistosoma mansoni infection: evaluation of morbidity

High burden of Schistosoma mansoni infection in school-aged children in Marolambo District, Madagascar

Background

A school-based survey was undertaken to assess prevalence and infection intensity of schistosomiasis in school-aged children in the Marolambo District of Madagascar.

Methods

School-aged children from six purposively selected schools were tested for Schistosoma haematobium by urine filtration and Schistosoma mansoni using circulating cathodic antigen (CCA) and Kato-Katz stool analysis. The investigators did not address soil-transmitted helminths (STH) in this study.

Results

Of 399 school-aged children screened, 93.7% were infected with S. mansoni based on CCA analysis. Kato-Katz analysis of stool revealed S. mansoni infection in 73.6% (215/ 292). Heavy infections (> 400 eggs per gram) were common (32.1%; 69/ 215), with a mean of 482 eggs per gram of stool. Moderate infection intensities were detected in 31.2% (67/ 215) and light infection intensities in 36.7% (79/ 215) of infected participants. No infection with S. haematobium was detected by urine filtration.

Conclusions

Intestinal schistosomiasis appears a considerable public health issue in this remote area of Madagascar where there is a pressing need for mass drug administration.

Human schistosomiasis

Human schistosomiasis--or bilharzia--is a parasitic disease caused by trematode flukes of the genus Schistosoma. By conservative estimates, at least 230 million people worldwide are infected with Schistosoma spp. Adult schistosome worms colonise human blood vessels for years, successfully evading the immune system while excreting hundreds to thousands of eggs daily, which must either leave the body in excreta or become trapped in nearby tissues. Trapped eggs induce a distinct immune-mediated granulomatous response that causes local and systemic pathological effects ranging from anaemia, growth stunting, impaired cognition, and decreased physical fitness, to organ-specific effects such as severe hepatosplenism, periportal fibrosis with portal hypertension, and urogenital inflammation and scarring. At present, preventive public health measures in endemic regions consist of treatment once every 1 or 2 years with the isoquinolinone drug, praziquantel, to suppress morbidity. In some locations, elimination of transmission is now the goal; however, more sensitive diagnostics are needed in both the field and clinics, and integrated environmental and health-care management will be needed to ensure elimination.

Cytokine and Chemokine Profile in Individuals with Different Degrees of Periportal Fibrosis due to Schistosoma mansoni Infection

Periportal fibrosis in schistosomiasis has been associated to the host immune response to parasite antigens. We evaluated the immune response in S. mansoni infected individuals with different degrees of periportal fibrosis. Cytokine and chemokines were measured in serum and in supernatants of PBMC cultures stimulated with the soluble adult worm (SWAP) or egg (SEA) antigens, using a sandwich ELISA. The levels of IL-5 in response to SEA were higher in individuals with moderate to severe fibrosis (310.9 pg/mL) compared to individuals without fibrosis (36.8 pg/mL; P = 0.0418). There was also a higher production of TNF-α in cultures stimulated with SWAP in patients with insipient fibrosis (1446 pg/mL) compared to those without fibrosis (756.1 pg/mL; P = 0.0319). The serum levels of IL-13 and MIP-1α were higher in subjects without fibrosis than in those with moderate to severe fibrosis. However a positive association between serum levels of IL-13, TNF-α, MIP-1α, and RANTES and S. mansoni parasite burden was found. From these data we conclude that IL-5 and TNF-α may participate in liver pathology in schistosomiasis. The positive association between IL-13, TNF-α, MIP-1α, and RANTES with parasite burden, however, might predict the development of liver pathology.

Comparison between clinical and ultrasonographic findings in cases of periportal fibrosis in an endemic area for schistosomiasis mansoni in Brazil

INTRODUCTION: Abdominal palpation and ultrasound findings among patients from an endemic area for schistosomiasis in Brazil who had been followed up for 27 years were compared. METHODS: In 2004, 411 patients from Brejo do Espírito Santo, in the State of Bahia, were selected for the present investigation after giving their written informed consent. Based on clinical data, they were divided into three groups: 41 patients with evidence of liver fibrosis in 2004 (Group 1); 102 patients with evidence of liver fibrosis in the past (1976-1989) but not in 2004 (Group 2); and 268 patients without evidence of liver fibrosis at any time during the 27-year follow-up (Group 3). All of the patients underwent abdominal ultrasound in which the examiner did not know the result from the clinical examination. The data were stored in a database. RESULTS: The prevalence of periportal fibrosis on ultrasound was 82.9%, 56.9% and 13.4% in Groups 1, 2 and 3, respectively. In the presence of hard, nodular liver or prominent left lobe and a hard palpable spleen, ultrasound revealed periportal fibrosis in 70.9%. However, periportal fibrosis was diagnosed using ultrasound in 25.4% of the patients in the absence of clinical evidence of liver involvement. Thus, ultrasound diagnosed periportal fibrosis 3.1 times more frequently than clinical examination did. CONCLUSIONS: Although clinical examination is important in evaluating morbidity due to Manson's schistosomiasis in endemic areas, ultrasound is more accurate in diagnosing liver involvement and periportal fibrosis.

Evaluation of schistosoma mansoni morbidity one year after praziquantel treatment in rhino cAMP and obongi in west nile, Uganda

An evaluation study on reversibility of Schistosoma mansoni induced periportal fibrosis (PF) morbidity following treatment with praziquantel, 40mg/kg body weight after one year, was carried out in Rhino Camp and Obongi all are West Nile districts in northern Uganda. To assess the reversibility of Schistosoma (S) mansoni induced PFs morbidity following treatment with praziquantel, 40mg/kg body weight after one year. The design was a Prospective cohorts study; and the setting was a busy canoe landing sites along Albert Nile in Schistosoma (S) mansoni hyperendemic areas of Rhino Camp and Obongi fishing village were selected for the study. Previously in 2005, 1562 people including fishermen and women, school pupils, teachers, and civil servants were studied in both fishing villages for S. mansoni using Kato/Katz stool smear method. Abdominal ultrasonography and sonomorphological abnormalities of periportal fibrosis were performed with Aloka portable ultrasound machine (Hellige, Freiburg, Germany) fitted with a convex probe of 3.5 mega Hertz was also performed in the field clinic on all patients who had S. mansoni eggs in their faeces. The sonomorphological abnormalities of periportal fibrosis were categorised and organomorphometry of liver and spleen was done. One thousand two hundred and seventy three 1273 (81.5%) patients in Rhino Camp and Obongi fishing villages were found to be excreting from 100 to ≥ 500 eggs per gram (epg) of faeces of S. mansoni eggs. Two hundred and eighty nine (18.5%) did not have eggs of S.mansoni in their faeces. All the 1273 patients secreting eggs of S.mansoni in their stool in Rhino Camp and Obongi fishing villages had abdominal ultrasonography and sonomorphological abnormalities of periportal fibrosis. Eight hundred and forty 840 (66%) although excreted S. mansoni eggs in their stool had Pf (0); Pf grade (I), n=259 (20.3%); Pf grade (II) n =147 (11.5%); and Pf grade (III) n=27 (2.1%) were observed.

Schistosoma mansoni morbidity among adults in two villages along Lake Victoria shores in Mwanza District, Tanzania

The study aimed to describe morbidity patterns due to intestinal schistosomiasis in adults living in two villages along the southern shores of Lake Victoria, Mwanza District, Tanzania. Nine hundred and fifty persons from Msozi and 497 from Sangabuye, aged between 14 and 87 years, were examined by abdominal ultrasound according to the Niamey protocol. Liver image patterns (LIP) A and B were considered normal and C-F as distinct periportal fibrosis (PPF). The frequency of PPF was higher in Msozi (41.5%) than in Sangabuye (16.7%) (P<0.001) and was associated with high prevalence and intensity of Schistosoma mansoni infection. PPF was shown to be more common in males than females. Abnormal increase of segmental branch wall thickness (SBWT) and dilated portal vein diameter (PVD) were also more common among males than females. Hepatomegaly and splenomegaly were frequently encountered in both villages. The LIPs were positively correlated to size of SBWT and PVD but not to size of left liver lobe or spleen. In the study communities the risk of developing PPF differed greatly among individuals depending on various risk factors especially alcohol consumption.

[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.

ASPECTOS ULTRA-SONOGRÁFICOS DA ESQUISTOSSOMOSE HEPATOESPLÊNICA

A ultra-sonografia representa uma importante contribuição no diagnóstico da forma hepatoesplênica da esquistossomose. A ultra-sonografia permite a identificação das principais alterações, como espessamento periportal, perivesicular, aumento do lobo hepático esquerdo, redução do lobo hepático direito e esplenomegalia. Adicionalmente, os padrões hemodinâmicos podem ser avaliados com o Doppler, sendo possível a análise das veias porta, mesentérica superior e esplênica, além de facilitar o estudo dos vasos venosos colaterais. Em áreas endêmicas, a ultra-sonografia assume papel de destaque, sendo superior à avaliação clínica na identificação da hepatoesplenomegalia e possibilitando o acompanhamento dos pacientes submetidos a tratamento clínico. Neste trabalho, os autores apresentam uma revisão dos principais achados sonográficos e ao Doppler da esquistossomose hepatoesplênica, sendo demonstrada, também, a relação destes achados com os aspectos clínico-patológicos desta doença.

Efficacy of praziquantel against Schistosoma mansoni with particular consideration for intensity of infection

Chemotherapy with praziquantel is the cornerstone of schistosomiasis control. In view of recent concern about tolerance or resistance to praziquantel, monitoring its efficacy in different epidemiological settings is required. We report a study among 253 schoolchildren in an area highly endemic for Schistosoma mansoni in western Côte d'Ivoire. After examining four consecutive stool specimens from each child, the first praziquantel treatment at 60 mg/kg divided into two doses was administered. Four weeks later, stool specimens were again screened over 4 consecutive days and revealed a cure rate of 71.6% and an egg reduction rate of 79.9%. There was a significant association between cure rate and intensity of infection prior to treatment with highest cure rates observed in light infections (P < 0.01). Praziquantel, at a single dose of 40 mg/kg, was again administered 35 days after the first treatment. The overall cure and egg reduction rates increased considerably. The association between cure rate and intensity of infection prior to the second treatment was significant but less pronounced. Twenty-two children remained S. mansoni positive after the two chemotherapy campaigns, and interestingly, many of these were only identified after repeated stool examinations. We argue that pre-patent infections may account for some of these 'treatment failures'. However, further studies in other endemic settings are needed, with parasitological diagnoses having a high sensitivity.

Repeated exposure induces periportal fibrosis in Schistosoma mansoni-infected baboons: role of TGF-beta and IL-4

Recently, we observed that repeated Schistosoma mansoni infection and treatment boost Th2-associated cytokines and TGF-beta production in baboons. Other studies have shown that some chronically infected baboons develop hepatic fibrosis. Because TGF-beta, IL-2, and IL-4 have been shown to participate in development of fibrosis in murine schistosomiasis, the present study examined whether repeated exposure stimulates hepatic fibrosis in olive baboons. To test this hypothesis, animals were exposed to similar numbers of S. mansoni cercariae given once or repeatedly. After 19 wk of infection, animals were cured with praziquantel and reinfected once or multiple times. Hepatic granulomatous inflammation and fibrosis were assessed from serial liver biopsies taken at weeks 6, 9, and 16 after reinfection and egg Ag (schistosome egg Ag)-specific cytokine production by PBMC were measured simultaneously. Periportal fibroblast infiltration and extracellular matrix deposition (fibrosis), angiogenesis, and biliary duct hyperplasia developed in some animals. The presence and amount of fibrosis directly correlated with the frequency of exposure. Fibrosis was not associated with adult worm or tissue egg burden. The amount of fibrosis correlated with increased schistosome egg Ag-driven TGF-beta at 6, 9, and 16 wk postinfection (rs = 0.9, 0.8, and 0.54, respectively, all p < 0.01) and IL-4 production (p = 0.02) at 16 wk postinfection and not IFN-gamma, IL-2, IL-5, or IL-10. These data suggest that repeated exposure is a risk factor for periportal fibrosis by a mechanism that primes lymphocytes to produce increased levels of profibrotic molecules that include TGF-beta and IL-4.

Severe hepatic fibrosis in Schistosoma mansoni infection is controlled by a major locus that is closely linked to the interferon-gamma receptor gene

Lethal disease due to hepatic periportal fibrosis occurs in 2%-10% of subjects infected by Schistosoma mansoni in endemic regions such as Sudan. It is unknown why few infected individuals present with severe disease, and inherited factors may play a role in fibrosis development. Schistosoma mansoni infection levels have been shown to be controlled by a locus that maps to chromosome 5q31-q33. To investigate the genetic control of severe hepatic fibrosis (assessed by ultrasound examination) causing portal hypertension, a segregation analysis was performed in 65 Sudanese pedigrees from the same village. Results provide evidence for a codominant major gene, with.16 as the estimated allele A frequency predisposing to advanced periportal fibrosis. For AA males, AA females, and Aa males a 50% penetrance is reached after, respectively, 9, 14, and 19 years of residency in the area, whereas for other subjects the penetrance remains <.02 after 20 years of exposure. Linkage analysis performed in four candidate regions shows that this major locus maps to chromosome 6q22-q23 and that it is closely linked (multipoint LOD score 3.12) to the IFN-gammaR1 gene encoding the receptor of the strongly antifibrogenic cytokine interferon-gamma. These results show that infection levels and advanced hepatic fibrosis in human schistosomiasis are controlled by distinct loci; they suggest that polymorphisms within the IFN-gammaR1 gene could determine severe hepatic disease due to S. mansoni infection and that the IFN-gammaR1 gene is a strong candidate for the control of abnormal fibrosis observed in other diseases.

High Levels of TNF, Soluble TNF Receptors, Soluble ICAM-1, and IFN-γ, but Low Levels of IL-5, Are Associated with Hepatosplenic Disease in Human Schistosomiasis Mansoni

In a case-control study based in two areas of Kenya, hepatosplenic schistosomiasis mansoni was shown to be linked with low levels of IL-5 and with correspondingly high IFN-γ, TNF, and circulating soluble TNF receptor I (sTNFR-I), sTNFR-II, and sICAM-1. PBMC from the hepatosplenic cases responded to in vitro Ag stimulation with significantly higher levels of IFN-γ and TNF, but lower levels of IL-5, compared with nonhepatosplenic controls matched for age and infection intensity. Most of these correlations were confounded by differences between geographical areas. However, principle component analysis identified a high IFN-γ and TNF, and low IL-5 axis in the data as the first principle component; this was significantly associated with hepatosplenomegaly (p &lt; 0.0005) even after controlling for area. High plasma levels of sTNFR-I (p &lt; 0.001), sTNFR-II, (p &lt; 0.0001), and sICAM-1 (p &lt; 0.009) were also significantly associated with hepatosplenomegaly, independently of area, in the case of the soluble forms of both TNF receptors. These parameters were negatively related to IL-5. These results suggest that proinflammatory cytokines are involved in the hepatosplenic disease process in infected individuals who have low anti-inflammatory Th2 responses and that sTNFR may be a useful circulating marker for this disease process, perhaps reflecting the level of TNF activity in hepatic tissues.

Ultrasonography of periportal fibrosis in schistosomiasis mansoni in Brazil

In patients with hepatosplenic schistosomiasis, characteristic thickening of the walls of the portal vein in the hilus and its central and peripheral branches is observed. In an area of high prevalence of the disease in Brazil, 424 individuals older than 5 years have been examined by abdominal ultrasonography and 146 presented fibrosis, classified as central in 31 (21%), peripheral in 56 (38%), and both central and peripheral in 59 (40%). The mean ages of the subjects in the 3 groups were 45.7, 24.1 and 31.9 years, respectively (P < 0.05). The presence of central fibrosis was associated with the presence of peripheral fibrosis (odds ratio 10.7, P < 0.000001). Splenomegaly was found in 16% and 15% of individuals with peripheral and both central and peripheral fibrosis, respectively. No subject with central but no peripheral fibrosis and splenomegaly was identified. We conclude that central fibrosis occurs among older subjects but should not be considered a criterion for advanced disease.

Occurrence of a community with high morbidity associated with Schistosoma mansoni infection regardless of low infection intensity in north-east Brazil

To establish the relationship between schistosome-associated morbidity and infection intensity in northeast Brazil, a parasitological and ultrasonographical study was carried out on 484 inhabitants of 4 villages (I, II, III and IV) in São Lourenço da Mata, Pernambuco, Brazil, where schistosomiasis is endemic. Quantitative stool examination using Knight's method demonstrated a high prevalence and moderate intensity of Schistosoma mansoni infection, and also that the subjects in village IV had a significantly lower prevalence and intensity of infection than those of the other villages. By ultrasonography, periportal fibrosis (PPF) and splenomegaly were found in 52% of the 299 infected subjects and 66% of the 146 infected subjects aged over 16 years old, respectively; 32% and 31% of the 299 infected subjects had abnormally high values of total bile acid (TBA) and alkaline phosphatase (ALP) activity, respectively. Liver and spleen size, PPF, and serum level of TBA and ALP were not correlated with infection intensity. There was no significant difference in the morbidity assessed by liver and spleen size, PPF, and serum analysis between the subjects in village IV and the other villages. These findings suggest the occurrence of a community with high morbidity associated with schistosomiasis regardless of low infection intensity.

Pathogenetic factors of acute schistosomiasis mansoni: correlation of worm burden, IgE, blood eosinophilia and intensity of clinical manifestations

A clinical study of 34 previously healthy young patients simultaneously infected in an endemic area of schistosomiasis mansoni is presented, emphasizing the initial phase of the infection. Its intensity was established according to the occurrence, intensity, and duration of the signs and symptoms in order to investigate the possible correlations between the worm burden (estimated by the number of eggs in faeces), the blood eosinophilia and specific levels of IgE (estimated by the area of immediate intradermal reaction), with the clinical manifestations. A significant but low-level association was found between the worm burden and morbidity, suggesting that multiple factors, besides worm burden itself, may contribute to the pathogenesis of the disease.

Ultrasonographical assessment of morbidity in schistosomiasis mansoni in Madagascar: a community-based study in a rural population

Between June and November 1993, a parasitological, clinical and ultrasonographical survey was carried out in the mid west of Madagascar, among the whole population of a village where Schistosoma mansoni was endemic. S. mansoni eggs were found in the stools of 61.8% of the 544 individuals examined; the highest prevalence of infection (85.7%) was observed in the 15-19 years old age group. The most intense infections were recorded in the 10-14 years age group, in which the geometric mean egg count was 265 eggs/g of faeces and 34.3% of the individuals excreted more than 400 eggs/g. The egg count decreased steadily from the age of 15 years. Ultrasonographical examination was performed in 482 inhabitants older than 2 years: 29% of them presented definite schistosome associated liver alterations according to the proposals for staging S. mansoni infection made by the World Health Organization Cairo working group. Stage 3 was never observed in subjects under 30 years old. This is consistent with the need for a long-standing infection before serious lesions occur. A significant relationship between egg count and degree of liver alterations was found only in the 20-29 years age group.

Ultrasonography of ureteric abnormalities induced by Schistosoma haematobium infection before and after praziquantel treatment

OBJECTIVE

To describe the ultrasonographic appearance of ureteric lesions due to Schistosoma haematobium infection and to report prevalence rates of such lesions in endemic communities in Mali before and after praziquantel treatment.

SUBJECTS AND METHODS

The total population (n = 961) of three S. haematobium-endemic villages in Mali was examined ultrasonographically to detect urinary tract morbidity. Urine was tested for S. haematobium ova and for haematuria. An identical follow-up study was performed 1 year after mass treatment with praziquantel.

RESULTS

Prevalence rates of S. haematobium infection in the three villages were 53%, 72% and 73%. Ultrasonography revealed dilatation of the ureters in 143 subjects (15%). In 20 of these, mainly children and adolescents, thickening and irregularities of the ureteric wall with distal ureter obstruction were directly visualized on ultrasonography. Within the bladder of two others, an intraluminal structure of ureterocele-like appearance was seen. None of these alterations has been previously described as an ultrasonographic feature of schistosomal uropathy. Active S. haematobium infection and microhaematuria were found in 21 and 20 of these 22 subjects respectively. Significant renal obstruction was present in 10 of them. One year after treatment, an entirely normal urinary tract was found in 85% of 104 re-examined individuals who had had ureter dilatation. Ureteric wall thickening or ureterocele-like lesions had disappeared in 95% of subjects.

CONCLUSIONS

The role of ultrasound in the evaluation of schistosomal uropathy is confirmed. Ureteric wall abnormalities causing strictures and ureterocele-like lesions of the ostium must be regarded as further ultrasonographic features of this condition. The study documents the excellent reversibility of ureteric abnormalities after antischistosomal treatment in children and adolescents, thus emphasizing the need for early and efficient medical treatment of the infection.

An ultrasonographic study of liver fibrosis in patients infected with Schistosoma mansoni in north-east Brazil

Between August 1988 and July 1990, 176 patients with Schistosoma mansoni infection attending the University Hospital, Recife, Brazil received a complete clinical examination including stool examination for intestinal parasites, liver function tests, and ultrasonography. The majority were also examined by upper digestive tract endoscopy. The clinical distribution of their disease was as follows: 26.7% intestinal, 13.6% hepato-intestinal, 53.4% compensated hepatosplenic and 6.3% decompensated hepatosplenic. Infection intensity was high, with a median of 360 eggs/g of faeces. Ultrasonography showed a good correlation between the degree of hepatic periportal fibrosis and the clinical stage of disease (P < 0.0001). Of the patients with the intestinal form of schistosomiasis, 12.8% had grade I fibrosis and the others had no fibrosis; 33.3% of patients with hepatointestinal schistosomiasis had grade I fibrosis, 8.3% had grade II fibrosis, and 58.4% had no fibrosis; all the patients with hepatosplenic disease had grade II or grade III fibrosis. The degree of liver fibrosis detected by ultrasonography correlated with the degree of oesophageal varices detected by endoscopy (P = 0.0001). The degree of oesophageal varices also correlated with the presence of haemorrhage (P < 0.0001). Ultrasonography is considered superior to liver biopsy, permitting a dynamic approach to the study of schistosomiasis morbidity with precise diagnosis and simple sequential follow-up of post-treatment results.

Schistosomiasis japonica on Jishan Island, Jiangxi Province, People's Republic of China: persistence of hepatic fibrosis after reduction of the prevalence of infection with age

Hepatic fibrosis due to schistosomiasis japonica was examined by ultrasonography in a cross-sectional community study of 825 individuals on Jishan Island, Jiangxi Province, China. The prevalence of active infection was 39.4% with peak infection in the 10-19.9 years age group followed by a significant decline. A similar pattern was observed for intensity of infection. The prevalence of hepatomegaly in the midsternal line > or = 6 cm peaked at 60% in the fourth decade and remained elevated. A progressive increase in the severity of hepatic periportal fibrosis was observed with age, with advanced fibrosis peaking in the fifth decade. The proportion of individuals with advanced fibrosis was significantly greater in males than in females despite equivalent prevalence and intensity of schistosome infection. In addition, a positive association (P < 0.01) was found between periportal fibrosis and both hepatomegaly > or = 6 cm and splenomegaly. This study suggests that the natural history of schistosomiasis japonica in this hyperendemic community in China is marked by persistence of hepatomegaly and schistosome-induced periportal fibrosis in adults despite a decrease in the prevalence of infection.

Use of ultrasound in a study of schistosomal periportal fibrosis in rural Zimbabwe

Ultrasound was used to diagnose periportal fibrosis (PPF) in a rural Zimbabwean community where Schistosoma mansoni is endemic. Ultrasound findings were compared with stool microscopy and abdominal palpation in 492 adults (305 females). 47 (9.6%) had definite PPF. The prevalence of PPF increased with age (P < 0.001), while S. mansoni egg counts decreased with age. Even within age groups, egg count did not correlate with PPF. No association was found between lifetime alcohol consumption and the presence of PPF. Splenomegaly and mid-line enlargement of the liver were specific (97% and 94%) but insensitive (21% and 28%) markers for PPF. Spleen size varied with S. mansoni egg count independently of the presence or degree of PPF. Endoscopy of 18 patients with PPF revealed oesophageal varices in two, both of whom had severe PPF.

Sonographic organometry in Brazilian and Sudanese patients with hepatosplenic schistosomiasis mansoni and its relation to the risk of bleeding from oesophageal varices

Fifty-nine patients with hepatosplenic schistosomiasis mansoni were investigated by sonography in Northeast Brazil and Central Sudan. The sizes of the organs usually involved in this disease were quantitatively assessed according to a standardized protocol, and measurements were adjusted to the body height of the individual. The results were compared with those of healthy controls matched by sex, age, geographical origin and socio-economic status. Considerable differences were found between patients and controls as well as between residents from the two areas. The liver of both patients and controls from the Sudan was significantly smaller than that of patients and controls from Brazil. Only in Brazil, but not in the Sudan, was the left liver lobe larger in patients than in the controls. The diameter of the portal and the splenic vein, the spleen size and the thickness of the gallbladder wall were significantly increased in patients from both areas. The increase of the portal and splenic vein diameter was significantly correlated with the degree of hepatic periportal fibrosis and the frequency of bleeding from endoscopically proven oesophageal varices in the patients, irrespective of their geographic origin. In contrast, such correlations were not found for the degree of splenomegaly nor for the degree of gallbladder-wall thickening. It is concluded that standardized sonographic organometry permits the assessment of morbidity in hepatosplenic schistosomiasis mansoni under different endemic conditions. Especially the measurement of the portal vein diameter may allow estimation of the risk of gastrointestinal haemorrhage in these patients.

A review of the literature on the use of ultrasonography in schistosomiasis with special reference to its use in field studies

This review presents an outline of the pathology resulting from Schistosoma mansoni infections, and the ways in which it can be investigated. The use of ultrasonography is covered in detail. Ultrasonography can provide direct information about lesions in internal organs, and thus provide information about patterns of morbidity and about the regression of pathological changes after treatment. The method is non-invasive, and can be used under field conditions. Ultrasonography is valuable for the study of hepatosplenic pathology, to detect lesions such as the development of periportal fibrosis and the enlargement of the portal vein, which can indicate the development of portal hypertension. This may lead to a severe outcome, including bleeding from oesophageal varices, which is a principal cause of death from S. mansoni infection. A problem with the use of ultrasonography is that the mild lesions likely to be observed in population surveys are not always easy to assess. Ultrasonography has already been used in a number of epidemiological studies of S. mansoni infection, and has proved to be feasible and useful. However, the methodology used for ultrasound studies has varied considerably, so that it is difficult to make valid comparisons between results obtained in different places or at different times. A standardized methodology for making observations and recording the results is needed if the full potential benefit of using ultrasound in the monitoring of schistosomiasis control projects is to be realised.

Ultrasound in schistosomiasis — A critical look at methodological issues and potential applications

This is the concluding paper of a series on the use of diagnostic ultrasound in the investigation of schistosomiasis. An earlier chapter in the volume discussed standardization of the methodology, and of recording, when ultrasound is used for epidemiological purposes. The present paper discusses some other requirements for obtaining ultrasound data which can be used to make valid comparisons within and between studies. Since there is an inherent variability in the interpretation of results from ultrasound images, quality control and the training of observers are both essential. It is also necessary to collect more information for each endemic setting about possible concomitant diseases which might lead to misinterpretation of results. Furthermore, the analysis of the data obtained must be uniform if valid comparisons are to be made. A final section considers applications of ultrasonography in research and control programmes. The technique should make it possible to obtain a better understanding of the extent and distribution of organ damage due to schistosomal infection in different geographical areas, and of the way in which lesions develop over time, or may regress in response to treatment. Since ultrasonography will always remain a relatively labour-intensive and expensive technique, it is necessary to establish, in different settings, how its findings correlate with the results of parasitological, serological and biochemical tests. The ultimate aim is to build up a body of information on the potential of ultrasonography, in combination with other procedures, in the various possible approaches to morbidity control.

Inter-observer variance in ultrasonographical assessment of Schistosoma mansoni-related morbidity in young schoolchildren

49 Sudanese schoolchildren aged 6-9 years with Schistosoma mansoni infection were ultrasonographically examined by two independent observers in a double-blind fashion. The first observer recorded normal appearance of the liver in 23 cases, whereas the second observer recorded the appearance as normal in 33 cases. There were 23 concordant observations. For Grade I periportal fibrosis (PF), 13 observations were concordant. PF Grade II was rarely observed (2 versus 3 cases), and Grade III was not recorded at all. In total, 38 out of 49 observations were concordant (77.5%). These preliminary data from two ultrasound observers, from observations on a limited number of patients, can be seen as an indication of a potential inter-observer variation of around 20% for the distinction between the absence of PF and a low level of PF.