Evaluation of portal hypertension in cases of hepatosplenic schistosomiasis using ultrasound

Gender Linked Metric Analysis of Portal Vein: A Sonographic Appraisal

INTRODUCTION

Portal hypertension is one of the most mystifying and disconcerting abdominal ailment. Ultrasonography (USG) is an effective diagnostic tool for its prompt management. Knowledge of normal calibre of portal vein in a local setting is essential as literature reports contrasting values in different regions. It helps in early diagnosis of portal hypertension even before it is clinically manifested thereby assisting clinicians and interventional radiologists in pertinent management.

AIM

Study was aimed to evaluate the Portal Vein Diameter (PVD) and find its correlation with gender by using USG in North Indian population.

MATERIALS AND METHODS

A total of 300 healthy adults were included in the study. Portal vein diameter was measured in supine position and normal respiration by grey scale USG. The portal vein diameter was correlated with age and gender statistically using independent Student's t-test and ANOVA.

RESULTS

Mean PVD of (9.49±1.03 mm) was observed in the present cross-sectional study. Male showed a significantly higher mean PVD (9.70±1.02 mm) as compared to females (9.10±0.94 mm).

CONCLUSION

Scarcity of information concerning ultrasonographically measured standard portal vein diameter and inconstant values reported in literature necessitates the need for establishing local standard value. In the given subset of population the portal vein diameter was influenced by the gender. The information will be helpful in prompt diagnosis and management of portal hypertension.

Intestinal schistosomiasis and geohelminths of Ukara Island, North-Western Tanzania: prevalence, intensity of infection and associated risk factors among school children

Background

Schistosoma mansoni and soil-transmitted helminths (STH) are among the most prevalent and highly neglected tropical diseases in Tanzania. However, little is known on the distribution of these infections in rural settings, especially in the island areas on Lake Victoria. Identifying the local risk factors of S. mansoni and soil-transmitted helminths is one step towards understanding their transmission patterns and will facilitate the design of cost-effective intervention measures. The present study was therefore conducted to determine the prevalence, intensity of infection and risk factors associated with S. mansoni and soil-transmitted helminth infections among school children in Ukara Island.

Methods

This was a cross sectional study which enrolled 774 school children aged 4-15 years in 5 primary schools in Ukara Island, North-Western Tanzania. Single stool samples were collected, processed using the Kato Katz technique and examined for eggs of S. mansoni and geohelminths under a light microscope. A pre-tested questionnaire was used to collect socio-demographic information.

Results

Overall, 494/773 (63.91%, 95% CI; 45.19-90.36) of the study participants were infected with S. mansoni and the overall geometrical mean eggs per gram (GM-epg) of feaces were 323.41epg (95% CI: 281.09 – 372.11). The overall prevalence of soil-transmitted helminth (STH) was 6.73% (n = 52/773, 95% CI = 4.39 – 10.32) with the most prevalent species being hookworms, 5.69% (n = 44/773, 95% CI; 3.68 – 8.79). Location of school in the study villages (P < 0.0001), parent occupation, fishing (P < 0.03) and reported involvement in fishing activities (P < 0.048) remained significantly associated with the prevalence and intensity of S.mansoni infection.

Conclusion

Schistosoma mansoni infection is highly prevalent in the islands whereas the prevalence of soil-transmitted helminths is low. The risk of infection with S. mansoni and the intensity of infection increased along the shorelines of Lake Victoria. These findings call for the need to urgently implement integrated control interventions, starting with targeted mass drug administration.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-014-0612-5) contains supplementary material, which is available to authorized users.

Associating portal congestive gastropathy and hepatic fibrosis in hepatosplenic mansoni schistosomiasis

Upper digestive bleeding is one of the most serious complications of mansoni schistosomiasis, and portal congestive gastropathy (PCG) is responsible for 25-30% of the cases of bleeding instead of bleeding due to esophageal varices. This study aimed to investigate the association between PCG with parameters of portal hypertension and the intensity of periportal fibrosis assessed by ultrasonography, in patients with mansoni schistosomiasis. A prospective study was made of 71 patients whether or not they had a history of upper digestive bleeding, and who had not been previously treated for portal hypertension (splenectomy, use of beta blockers or endoscopic treatment). Patients with other liver diseases were excluded. After signing a form of consent, the patients underwent endoscopy, as well as ultrasonography of the abdomen, and hematological, biochemical and viral markers tests. Chi-square and Fischer's exact tests were used in the statistical analysis. The mean age of the 71 patients was 50 ± 14.5 years of whom 59.2% were women. 45.1% had antecedents of upper digestive bleeding. PCG was observed in 39 patients (54.9%): severe in 8.5%, and mild in 46.5%. A positive association was observed between PCG and the grade of esophageal varices (p=0.017); and the pattern of periportal fibrosis (p=0.041). A negative association was observed between PCG and red spots on the varices (p=0.024). PCG in patients with mansoni schistosomiasis not submitted to treatment for portal hypertension is associated with the sonographic pattern of hepatic fibrosis, as well as with the grade of esophageal varices.

Ultrasound and magnetic resonance imaging findings in Schistosomiasis mansoni: expanded gallbladder fossa and fatty hilum signs

INTRODUCTION: There is no study relating magnetic resonance imaging (MRI) to ultrasound (US) findings in patients with Schistosomiasis mansoni. Our aim was to describe MRI findings inpatients with schistosomal liver disease identified by US. METHODS: Fifty-four patients (mean age 41.6±13.5years) from an area endemic for Schistosomiasis mansoni were selected for this study.All had US indicating liver schistosomal fibrosis and were evaluated with MRI performed witha 1.5-T superconducting magnet unit (Sigma). RESULTS: Forty-seven (87%) of the 54 patientsshowing signs of periportal fibrosis identified through US investigation had confirmed diagnosesby MRI. In the seven discordant cases (13%), MRI revealed fat tissue filling in the hilar periportalspace where US indicated isolated thickening around the main portal vein at its point of entryto the liver. We named this the fatty hilum sign. One of the 47 patients with MRI evidence ofperiportal fibrosis had had his gallbladder removed previously. Thirty-five (76.1%) of the other46 patients had an expanded gallbladder fossa filled with fat tissue, whereas MRI of the remainingeleven showed pericholecystic signs of fibrosis. CONCLUSIONS: Echogenic thickening of thegallbladder wall and of the main portal vein wall heretofore attributed to fibrosis were frequentlyidentified as fat tissue in MRI. However, the gallbladder wall thickening shown in US (expandedgallbladder fossa in MRI) is probably secondary to combined hepatic morphologic changes inschistosomiasis, representing severe liver involvement.

Imaging techniques in the evaluation of morbidity in schistosomiasis mansoni

Over the last 20 years a great advance has been observed in many aspects of medicine, and the advent of novel imaging techniques is certainly amongst the most important. In schistosomiasis these new methods caused a revolution in the definition of the clinical forms of the disease and in the evaluation of its complications, such as, liver fibrosis, pulmonary hypertension and neuroschistosomiasis, as never before. Herein we present an overview of the image methods used to diagnose schistosomiasis mansoni nowadays.

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.

Disagreement between ultrasound and magnetic resonance imaging in the identification of schistosomal periportal fibrosis

Abdominal ultrasound (US) has been widely used in the evaluation of patients with schistosomiasis mansoni. It represents an important indirect method of diagnosis and classification of the disease, and it has also been used as a tool in the evaluation of therapeutic response and regression of fibrosis. We describe the case of a man in whom US showed solid evidence of schistosomal periportal fibrosis and magnetic resonance imaging revealed that periportal signal alteration corresponded to adipose tissue which entered the liver together with the portal vein.

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.

IFN-gamma polymorphisms (IFN-gamma +2109 and IFN-gamma +3810) are associated with severe hepatic fibrosis in human hepatic schistosomiasis (Schistosoma mansoni)

Schistosome infection is a major public health concern affecting millions of people living in tropical regions of Africa, Asia, and South America. Schistosomes cause mild clinical symptoms in most subjects, whereas a small proportion of individuals presents severe clinical disease (as periportal fibrosis (PPF)) that may lead to death. Severe PPF results from an abnormal deposition of extracellular matrix proteins in the periportal spaces due to a chronic inflammation triggered by eggs and schistosome Ags. Extracellular matrix protein production is regulated by a number of cytokines, including IFN-gamma. We have now screened putative polymorphic sites within this gene in a population living in an endemic area for Schistosoma mansoni. Two polymorphisms located in the third intron of the IFN-gamma gene are associated with PPF. The IFN-gamma +2109 A/G polymorphism is associated with a higher risk for developing PPF, whereas the IFN-gamma +3810 G/A polymorphism is associated with less PPF. The polymorphisms result in changes in nuclear protein interactions with the intronic regions of the gene, suggesting that they may modify IFN-gamma mRNA expression. These results are consistent with the results of previous studies. Indeed, PPF is controlled by a major locus located on chromosome 6q22-q23, closely linked to the gene encoding the alpha-chain of the IFN-gamma receptor, and low IFN-gamma producers have been shown to have an increased risk of severe PPF. Together, these observations support the view that IFN-gamma expression and subsequent signal transduction play a critical role in the control of PPF in human hepatic schistosome infection (S. mansoni).

Efficacy and side effects of praziquantel treatment in a highly endemicSchistosoma mansoni focus at Lake Albert, Uganda

The aim of the study was to assess the efficacy and side effects following single and repeated (6 weeks apart) praziquantel treatment (40 mg/kg) in a Schistosoma mansoni-endemic focus with long-standing transmission at Lake Albert in Uganda between December 1996 and January 1997. The results were based on 482 individuals, randomly representing all age and both gender groups. The cure rate following the first and second treatments was 41.9% and 69.1%, respectively. The cure rate was higher in adults than in children, irrespective of intensity of infection. In addition, the cure rate declined markedly with increasing intensity of infection. The reduction in intensity of infection was marked, being 97.7% and 99.6% after the first and second treatments, respectively. A pre- and post-treatment symptom questionnaire revealed a broad range of side effects, including abdominal pain and diarrhoea. However, no serious or long-lasting complications affecting compliance were observed. The marked reductions in faecal egg excretion and the acceptable level of side effects point to a single praziquantel treatment (40mg/kg) as the strategy of choice in such a highly endemic S. mansoni focus.

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.

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.

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.

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

Four hundred and seventy villagers of Ndombo, a village with recently established intensive transmission of Schistosoma mansoni in the Senegal River Basin, were enrolled in a study with the intention to assess hepatosplenic morbidity. All patients were examined parasitologically and by ultrasound. Hepatic fibrosis serum markers were determined in 153 adult patients (aminoterminal propeptide of procollagen type III, hyaluronan and laminin). By ultrasound, about 60% of the patients showed early stages of hepatic involvement, 3% of the patients unequivocally showed severe hepatosplenic pathology (grade 3 according to the Managil classification), whereas in another study performed in the same village 3 years earlier, no patients with severe hepatosplenic pathology had been found. No correlation between the aminoterminal propeptide of procollagen type III, hyaluronan or laminin and the ultrasound findings could be established. These hepatic fibrosis serum markers do not seem to be a sensitive method to detect early hepatic fibrosis in schistosomiasis.

Predictors of upper gastrointestinal bleeding in patients with schistosomal periportal fibrosis

A case-control study was conducted between 1985 and 1987 in the Gezira-Managil area of central Sudan to assess the major predictors of haematemesis. Eighty-four patients who had suffered at least one attack of oesophageal bleeding and had schistosomal periportal fibrosis demonstrated by ultrasonography were compared with 173 subjects without bleeding but with ultrasonographic evidence of periportal fibrosis. A splenic longitudinal dimension of more than 11 cm, periportal fibrosis worse than grade I and varices more than grade I were independently associated with a significant risk of variceal bleeding. Age, sex, presence of a palpable liver and portal vein diameter were not associated with a significant risk of bleeding after adjustment for potential confounding variables. Factors identified in this study could be helpful in the prophylactic management of patients with complicated schistosomiasis.

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.

Sonographic changes following splenectomy for portal hypertension in Schistosoma mansoni

Eleven patients with portal hypertension due to infection with Schistosoma mansoni underwent splenectomy and devascularization operations. The patients were examined with ultrasound once preoperatively and twice postoperatively over a period of about 6 months. Following surgery there was significant and sequential reduction in the diameter of the portal vein at the hilum and the splenic vein at the pancreas. The liver lengths and index of liver size did not change significantly. No changes in the degree of periportal fibrosis could be detected.

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.

Sonographic studies of schoolchildren in a village endemic for Schistosoma mansoni

Parasitological, clinical, and sonographic examinations were performed on 309 school children in a village endemic for schistosomiasis mansoni. Data from the 255 denying treatment within the previous 2 years were analysed separately. On a single Kato examination 42% were uninfected; the remainder had light (26%), moderate (21%), or heavy (11%) infections with Schistosoma mansoni. Hepatomegaly (53%) and palpable spleens (35%) were common but clinical and parasitological findings often were unrelated. Abdominal sonography also demonstrated a high frequency of hepatomegaly (82%) and splenomegaly (49%). Sonographically determined liver span and spleen size correlated with the egg count. Sonographic lesions of periportal fibrosis of schistosomiasis mansoni with thickening of portal tracts and portal vein walls were frequently present and more common in infected than in uninfected children, and were correlated with the number of S. mansoni ova in the stool. Ultrasonographically detected periportal fibrosis was a reliable measurement of the prevalence and morbidity of schistosomiasis mansoni in this population, and provided very useful information, even when the parasitological and clinical findings were equivocal.

Ultrasound demonstration of changes in the normal portal venous system following a meal

Eating might be expected to change vessel size within the portal venous system. The diameters of the portal and superior mesenteric veins were measured in thirteen normal individuals using B-mode ultrasound, initially fasting and then following a meal. We have shown a 50% increase in the diameter of both these vessels occurring between thirty minutes and one hour after a meal. The significance of this is discussed.