Determinants of infection with schistosomiasis haematobia using logistic regression

A population-based stratified random sample of 10,039 inhabitants of rural communities in Minya Governorate, Egypt, were evaluated for risk factors for Schistosoma haematobium infection using multivariate analysis. Data were obtained by personal interview recording demographics, information on exposure to canal water, history of infection, and other risk factors for infection and examining urine samples for S. haematobium ova. Logistic regression analysis was used to adjust for confounders while assessing the role of each risk factor for infection. Using logistic regression allowed detection of several confounders and interactions which influenced other independent variables. Differences in exposure patterns to canal water among age and gender subgroups explained only a small portion of the variation in infection rates, thus favoring the alternative explanation: development of age-acquired immunity. The association of age with reduced prevalence of S. haematobium was the only relationship increasing (odds ratio [OR] = 2.95-4.30) with logistic regression. Male gender was a risk factor for infection but did not increase with logistic regression (OR = 2.33-2.03). The protective effects of education, only noted in schoolage children (OR = 0.59-0.51), were believed to be due to a school-based screening and treatment program.

Hematuria and proteinuria as predictors of Schistosoma haematobium infection

An investigation of a population-based stratified random sample of 11,970 inhabitants of Minya Governorate in Egypt included examining urine specimens for Schistosoma haematobium ova using the filtration technique and for hematuria and proteinuria using reagent strips. Age- and gender-specific sensitivity, specificity, predictive values, and likelihood ratios of reagent strip-detected hematuria and proteinuria as indicators of S. haematobium infection were assessed. Results showed that in this population with a 9.0% infection rate, sensitivity (from 45.9 to 70.9) and specificity (from 65.9 to 86.3) were much lower than in previous reports. The most clinically valuable parameters, positive predictive value (PPV), negative predictive value (NPV) and likelihood ratio (LR), were highest with the presence of hematuria > or = +++ and proteinuria > or = ++, especially in males less than 20 years of age. Using the LR allowed effective altering of the pretest probability of infection among age and gender subgroups. The study concluded that reagent strip-detected hematuria and proteinuria, although valuable, are less reliable predictors of S. haematobium within communities than previously reported and their usefulness is improved with stratification by age and gender. In addition, predictive values and likelihood ratios provide practical information for predicting the presence or absence of infection within population subgroups.

Utilization and cost of serologic tests for Lyme disease in Maryland

To ascertain use of serologic tests for Lyme disease (LD) in Maryland, all laboratories registered with the State Health Department were surveyed. Results show that from 1992 to 1995, 17 laboratories performed 100,000 serologic tests costing $7.1 million on Maryland residents; 90% of these tests were EIAs. The proportion of positive EIAs increased from 3.4% in 1992 to approximately 7.0% in 1994 and 1995, and the percentage of positive second tests (Western blot, WB) fell from 7.9% to 5.0%-5.5%. The large number of EIAs performed in comparison with the low incidence of LD in the state results in a low predictive value of a positive EIA test. Therefore, the WB is indicated to confirm equivocal and positive EIA tests when characteristic clinical findings of LD are not present. The 30,000 tests for LD performed annually on Maryland residents at a cost of over $2 million in direct medical costs must be added to the public health burden of LD in this state.

Evaluation of an ultrasonographic score for urinary bladder morbidity in Schistosoma haematobium infection

An ultrasonographic urinary bladder morbidity score was developed and tested in 510 patients with schistosomiasis haematobia, and then evaluated for screening 1,134 randomly selected children from villages endemic for Schistosoma haematobium. The ultrasonographic urinary bladder morbidity score had four grades ranging from normal to marked thickening of the urinary bladder wall or any polyps or masses. Among both patients and randomly screened subjects, the ultrasonographic score was greater (P = 0.01 and P < 0.01) in males than in females. Children examined in the clinic had higher (P = 0.03) ultrasonographic scores than adults. Infected subjects in communities were more likely (P < 0.001) to have urinary bladder morbidity than uninfected subjects, and clinic patients with egg counts > or = 20 eggs/10 ml of urine had higher (P = 0.03) ultrasonographic urinary bladder morbidity scores than those with lighter infections. The geometric mean egg count was higher (P = 0.04) in clinic patients with grade II and III lesions than in those with grade 0 and I lesions. There was progressive improvement of the grade of urinary bladder morbidity scores in patients treated with praziquantel at each follow-up examination (P < 0.001) and there was a positive relationship (P < 0.01) between urinary bladder morbidity scores and ultrasonographic-detected renal back pressure changes. The ultrasonographic urinary bladder morbidity score objectively measured the severity of urinary bladder morbidity and correlated with intensity of S. haematobium infection in our subjects. It can be used in evaluating both morbidity in patients and in community surveys and in following the outcome of chemotherapy.

Comparative evaluation of the use of artificial neural networks for modelling the epidemiology of schistosomiasis mansoni

There has been a marked increase in the application of approaches based on artificial intelligence (AI) in the field of computer science and medical diagnosis, but AI is still relatively unused in epidemiological settings. In this study we report results of the application of neural networks (NN; a special category of AI) to schistosomiasis. It was possible to design an NN structure which can process and fit epidemiological data collected from 251 schoolchildren in Egypt using the first year's data to predict second and third years' infection rates. Data collected over 3 years included age, gender, exposure to canal water and agricultural activities, medical history and examination, and stool and urine parasitology. Schistosoma mansoni infection rates were 50%, 78% and 66% at the baseline and the 2 follow-up periods, respectively. NN modelling was based on the standard back-propagation algorithm, in which we built a suitable configuration of the network, using the first year's data, that optimized performance. It was implemented on an IBM compatible computer using commercially available software. The performance of the NN model in the first year compared favourably with logistic regression (NN sensitivity = 83% (95% confidence interval [CI] 78-88%) and positive predictive value (PPV) = 63% (95% CI 57-69%); logistic regression sensitivity = 66% (95% CI 60%-72%) and PPV = 59% (95% CI 53%-65%). The NN model generalized the criteria for predicting infection over time better than logistic regression and showed more stability over time, as it retained its sensitivity and specificity and had better false positive and negative profiles than logistic regression. The potential of NN-based models to analyse and predict wide-scale control programme data, which are inevitably based on unstable egg excretion rates and insensitive laboratory techniques, is promising but still untapped.

Plasmodium falciparum circumsporozoite vaccine immunogenicity and efficacy trial with natural challenge quantitation in an area of endemic human malaria of Kenya

It has been hypothesized that antibody induced by Plasmodium falciparum circumsporozoite protein vaccine would be effective against endemic human malaria. In a malaria endemic region of Kenya, 76 volunteers, in 38 pairs sleeping adjacently, were immunized with subunit circumsporozoite protein Asn-Ala-Asn-Pro tetrapeptide repeat-pseudomonas toxin A, or hepatitis B vaccine. After quinine and doxcycycline, volunteers were followed for illness daily, parasitemia weekly, antibody, T-lymphocyte responses, and treated if indicated. Anopheles mosquitoes resting in houses were collected, and tested for P. falciparum antigen, or dissected for sporozoites and tested for blood meal ABO type and P. falciparum antigen. Vaccine was safe, with side-effects similar in both groups, and immunogenic, engendering IgG antibody as high as 600 micrograms ml-1, but did not increase the proportion of volunteers with T-lymphocyte responses. Estimation of P. falciparum challenge averaged 0.194 potentially infective Anopheles bites/volunteer/ day. Mosquito blood meals showed no difference in biting intensity between vaccine and control groups. Both groups had similar malaria-free survival curves, cumulative positive blood slides, cumulative parasites mm-3, and numbers of parasites mm-3 on first positive blood slide, during three post-vaccination observation periods. Every volunteer had P. falciparum parastemia at least once. Vaccinees had 82% and controls 89% incidences of symptomatic parasitemia (P = 0.514, efficacy 9%, statistical power 95% probability of efficacy < 50%). Vaccine-induced anti-sporozoite antibody was not protective in this study. Within designed statistical precisions the present study is in agreement with efficacy studies in Colombia, Venezuela and Tanzania.

The public health impact of Lyme disease in Maryland

The purpose of this study was to estimate the health burden imposed by Lyme disease (LD) in Maryland during 1992 and 1993. A cross-sectional 1-in-15 survey of physicians (total, 1200) in Maryland was conducted to estimate the incidence of diagnosed LD, presumptive cases of LD, patients with tick bites, and diagnostic tests ordered for LD. Results show that LD is underreported by 10- to 12-fold in Maryland, that 80% of cases are managed by primary care physicians, and that there is discordance between the actual clinical treatment of patients and the recommended approach. In addition, the much greater numbers of patients treated for presumptive LD, seen and given prophylaxis for tick bites, and having diagnostic tests indicate that real and perceived LD is a far greater public health problem and uses more medical resources than official surveillance data suggest.

Lyme disease surveillance in Maryland, 1992

The incidence of Lyme disease (LD) reported to the Maryland Department of Health and Mental Hygiene during 1992 was 6.5/100,000 population, ranging from 29.3 cases/100,000 on the Eastern Shore (74.4% of all cases) to no cases in the mountains of western Maryland. Among the 317 reported patients, 44.4% gave a history of tick exposure and 78.9% had positive serologic test results. For the 187 (59.0%) patients meeting the Centers for Disease Control and Prevention (CDC) surveillance case definition, erythema migrans (EM) occurred in 69.5%, with arthritic (26.7%), neurologic (13.4%), and cardiac (2.1%) manifestations being less frequent. Patients not meeting the surveillance case definition were significantly more likely to have influenza-like symptoms, a smaller rash, and arthralgia. Patients meeting the CDC criteria were more likely to have an onset during the major transmission season in the summer (odds ratio (OR): 2.1; confidence interval (CI): 1.2 to 3.6) since this was the time when most (115/130) patients with EM were detected. Positive serologic results were more likely (OR: 2.2; CI: 1.2 to 4.2) in those not meeting the case definition. The treatment given to patients thought to have LD was almost always that recommended in the literature and there was no difference between treatment prescribed for patients meeting and those not meeting the case definition. These data show that physicians in Maryland are treating many patients for LD who are clinically diagnosed as having LD (e.g., febrile patients with flulike symptoms, patients with arthralgias or erythematous rashes < 5 cm in size) and who have positive serologic test results but who do not meet the CDC surveillance case definition. These patients and the large number of unreported patients being seen and treated for LD or tick bites must be added to the overall burden of LD in the state.

Diagnosis and treatment of hepatic hydatid cysts with the aid of echo-guided percutaneous cyst puncture

The usefulness of echo-guided percutaneous cyst puncture in the diagnosis and treatment of hepatic hydatid cysts was assessed in a study of 45 patients referred to the Department of Tropical Medicine at Kasr El Aini Hospital in Cairo. All subjects had at least one hepatic cyst detected by ultrasonography (54 cysts in all), and 42 patients had positive results in serological tests for antibodies to Echinococcus granulosus. The majority of cysts were in the right hepatic lobe (40 cysts), were anechoic (51), and were rounded and smooth (49). All 45 active cysts (44 anechoic, rounded, and smooth; one anechoic and septated) yielded clear watery fluid containing scolices and exhibited elevated pressure on percutaneous puncture. In contrast, all nine inactive cysts yielded cloudy yellowish fluid without detectable scolices and did not display elevated pressure on puncture. The latter cysts were anechoic and elliptical (two cysts); anechoic and septated (one); anechoic with a calcified wall (one) or a detached germinal layer (two); or rounded with coarse echoes (three). Treatment by injection of a scolicidal agent (hypertonic saline) before withdrawal of the needle used for aspiration gave excellent results and was not associated with complications. Forty-three of the 45 patients had no clinical or ultrasonographic evidence of recurrent or new hepatic cysts after 3 years of follow-up.

High prevalence of hepatitis C in Egyptian patients with chronic liver disease

The highest prevalence rates of hepatitis C virus infection in the world have been recently reported among Egyptian blood donors and frequent recipients of transfusions and other blood products. This is the first report, however, demonstrating hepatitis C as the most frequent association with chronic liver disease in Egypt. Of 1023 patients referred to the Liver Institute in Menoufia governorate for evaluation of chronic liver disease, 752 (73.5%) had antibodies to hepatitis C compared with 168 (16.4%) with hepatitis B surface antigen. Hepatitis C antibody was more common in patients with active schistosomiasis and patients without hepatitis B surface antigenaemia. Of 100 patients having liver biopsies, histological findings consistent with chronic viral hepatitis or its complications were found in 89 and antibody to hepatitis C was present in 75 (84.3%) of these patients with chronic hepatitis, active cirrhosis or hepatocellular carcinoma. These data pointing to the importance of hepatitis C as a cause of chronic liver disease in Egypt emphasise the necessity of studies delineating its routes of transmission in this country.

High seroprevalence of hepatitis C infection among risk groups in Egypt

High prevalence rates of hepatitis C virus (HCV) were recently reported among Egyptian blood donors. To confirm these observations and estimate the magnitude of HCV infection in this country, we determined the prevalence of antibodies to HCV (anti-HCV) in samples collected in 1992 from seven different populations of children and adults living in Egypt. Anti-HCV was found in 12.1% of rural primary schoolchildren, 18.1% of residents of a rural village, 22.1% of army recruits, 16.4% of children with hepatosplenomegaly, 54.9% of hospitalized, multitransfused children, 46.2% of adults on hemodialysis, and 47.2% of adults with chronic liver disease or hepatoma. Age-related prevalence of anti-HCV in a random sample of 270 inhabitants of a rural village increased progressively from zero in those 5-10 years of age to 41% in adults greater than the age of 50. Although the increased prevalence of anti-HCV among children and adults with parenteral exposures and chronic liver disease was expected, the prevalence of anti-HCV among persons representing the general population of Egypt was strikingly high. These data demonstrate the magnitude of HCV infection and its importance in chronic liver disease in Egypt. Future studies are needed to determine the routes of transmission of HCV in this country.

Gastrointestinal manifestations of schistosomiasis

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Maryland physicians' survey on Lyme disease

In a survey of 252 physicians practicing in Maryland, 170 responders diagnosed 142 cases of Lyme disease (LB) during 1990 and 1991. About 80% of the cases were diagnosed by primary care physicians. The most common clinical finding, erythema migrans (EM), was reported in half the cases and arthritis was reported in a quarter. Only 22.2% had a history of a tick bite; serological tests were ordered in a third of the cases. EM was treated with oral antibiotics for 10-21 days. Most physicians treated Lyme arthritis with the same therapy, although some used intravenous ceftriaxone. The most commonly used treatment for neurologic or cardiac complications was intravenous ceftriaxone. These preliminary data suggest that LB may be diagnosed by Maryland physicians more frequently than syphilis and tuberculosis. The data also indicate LB is a much larger problem in Maryland than suggested by official reports to the Centers for Disease Control. The clinical characteristics of the illness and the antibiotics prescribed for it in Maryland are similar to those reported in northeastern states.

Antibiotic therapy for Lyme disease in Maryland

The recommended treatment of Lyme disease is evolving and important questions remain unanswered, such as (a) Are inexpensive oral regimens effective in curing acute illness and preventing arthritic, neurologic, and cardiac manifestations or are much more costly, and potentially toxic, intravenous antibiotics required? (b) Are relatively short 2- to 3-week courses of antibiotics sufficient or are prolonged regimens of a month, or more, better? This study reviews antibiotic therapy prescribed by Maryland physicians for the 283 cases reported in 1991 that meet the Centers for Disease Control and Prevention's case definition for Lyme disease. The purpose of the review was to obtain baseline information on the antibiotics being used by physicians in practice to treat patients that they believe have Lyme disease. The most frequently prescribed antibiotics for either the 60 percent of patients presenting with erythema migrans or the 40 percent with arthritic, neurologic, or cardiac manifestations were oral doxycycline (47 percent), tetracycline (11 percent), and amoxicillin (13 percent). Seventy-one percent of therapeutic courses were for 2 to 3 weeks. Amoxicillin was used in two-thirds of children younger than 8 years. Sixty (21 percent) received intravenous therapy, of which ceftriaxone, with or without other antibiotics, was almost always (95 percent) used. Intravenous therapy was more frequently given to those with arthritic, neurologic, and cardiac manifestations than to those with erythema migrans (odds ratio = 3.7) and to those with these systemic symptoms along with erythema migrans than to those with erythema migrans alone (odds ratio = 3.8). The average course was 2 days longer in treating those with arthritic, neurologic, or cardiac manifestations than in treating those with erythema migrans alone(P = 0.05).An epidemiologic assessment of antibiotics prescribed by the physicians in Maryland to treat Lyme disease in 1991 shows the choices, dosage, and duration of drugs generally followed those most frequently recommended in the literature. Also, it shows that efforts to educate physicians should be directed more towards the diagnosis rather than the treatment of Lyme disease.

Is Schistosoma mansoni replacing Schistosoma haematobium in the Fayoum?

Schistosoma mansoni is progressively replacing S. haematobium along the Nile River in Egypt. This change has occurred in the past 15-20 years following construction of the Aswan High Dam in the 1960s. The cause is a shift in relative abundance of the snail vectors Biomphalaria alexandrina and Bulinus truncatus. Biomphalaria is increasing while the latter has disappeared from a village in the Fayoum where formerly only schistosomiasis haematobia was endemic. A cross-sectional household survey in this village in 1991 showed the following prevalence values: S. mansoni, 22.3%; S. haematobium, 3.4%; and mixed infections, 2.8%. Only two children less than 10 years of age had S. haematobium infections. A review of the local Ministry of Health records showed that 1) both species were parasitologically diagnosed during the past 7.5 years, 2) Biomphalaria had been abundantly present in the local waterways for the past 10 years and has been found infected with S. mansoni since 1985, 3) Bulinus has not been detected in the local canals and drains since 1986 and the few found between 1981 and 1985 were not infected, and 4) Biomphalaria in this village and in two others in the Fayoum were believed infected by laborers from the Delta who helped build schools in 1984. This change in the distribution of schistosomiasis will impact upon public health and medical practice in Middle and Upper Egypt as it already has in Lower Egypt.

Foci of Schistosoma mansoni in Assiut province in middle Egypt

Following detection of Schistosoma mansoni in a 12 years old boy who had both schistosomal polyposis and periportal fibrosis with hepatosplenomegaly, epidemiological studies to confirm local transmission were performed in his and 30 other villages in Assiut Governorate, Egypt. The index case's brother and 6 of 380 inhabitants of his village who provided stool specimens were infected with S. mansoni and a farmer with dysentery and hepatosplenomegaly had a positive rectal snip biopsy. All had hepatic abnormalities on ultrasound examination. Two of 221 schoolchildren in another village had mixed infections with S. mansoni and S. haematobium; 17 others had only S. haematobium. None of 419 inhabitants living near the infected boys had S. mansoni infection. Snails from canals and drains near both villages were netted, identified, counted and checked for infection: in the second village one of 1039 Bulinus truncatus was infected with Schistosoma sp. but none of 859 Biomphalaria alexandrina was infected. Schistosomiasis mansoni is being focally transmitted in 2 villages in Assiut Governorate and appears to be spreading from Lower to Middle and Upper Egypt. We believe B. alexandrina, which has been present in some of the waterways for at least 15 years, were infected recently by local inhabitants returning from Iraq or by cattle traders or military recruits from the Delta.

Ultrasonographic prediction of esophageal varices in Schistosomiasis mansoni

Bleeding from esophageal varices is a common and serious problem in Schistosomiasis mansoni. A simple and accurate method of detection would facilitate measurement of individual and community morbidity and allow institution of preventive measures. An ultrasonographic scoring system grading periportal fibrosis, portal vein diameter, spleen size, and portasystemic anastomoses was evaluated as a predictor of esophageal varices and a past history of upper gastrointestinal hemorrhage in 43 patients with hepatosplenic schistosomiasis. Ultrasonographic variceal score correlated (r = 0.86, p < 0.001) with the endoscopic variceal grade. Patients with a sonographic score of 5 or greater were highly likely (21 of 23) to have varices of grade II or greater (sensitivity, 91.3%; specificity, 94.7%). Only those with sonographic scores of 5 or greater (15 of 23) had bled from esophageal varices. The ultrasonographic score provided a simple, inexpensive, accurate, and noninvasive means of screening individuals with hepatosplenic schistosomiasis for esophageal varices, and correlated strongly with prior gastrointestinal hemorrhage. It is not known whether a similar score would be useful in hepatic cirrhosis.

Abdominal ultrasonography for assessing morbidity from schistosomiasis. 2. Hospital studies

Abdominal ultrasound, which uses a pulse echo device to record reflected waves of a sound beam in 2 dimensions, has revolutionized the evaluation of schistosomal morbidity. It is relatively inexpensive, rapid, simple to perform and portable, causes no biological hazards to the subject and, because of its speed, is ideal for diagnosis and directing interventions, e.g., biopsies. Ultrasound complements or replaces intravenous pyelography, cystoscopy, endoscopy, liver biopsy, angiography and other invasive techniques for studying morbidity due to schistosomiasis. The sensitivity and specificity of ultrasound, in comparison to these other procedures, for detecting schistosomal lesions has been between 80% and 100%, with the exception of detection of hydroureter, ureteral calculi and calcified bladder. Ultrasound is the best method for measuring liver and spleen size and configuration; detecting and grading periportal fibrosis, portal hypertension, hydronephrosis and urinary bladder wall lesions; and for demonstrating renal and bladder stones.

Abdominal ultrasonography for assessing morbidity from schistosomiasis. 1. Community studies

Portable abdominal ultrasonography has been used to measure community morbidity from schistosomiasis in schoolchildren and cross-sectional population samples and to assess efficacy of chemotherapy. Periportal fibrosis and hepatosplenomegaly have been common findings, usually associated with each other and with prevalence and intensity of infection as measured by faecal Schistosoma mansoni ova excretion. Similar, less severe, lesions have been noted in subjects infected with S. haematobium. Inhabitants of villages where praziquantel therapy was systematically provided had less periportal fibrosis and hepatosplenomegaly than those living in nearby villages where treatment was not available. Community-based screening in S. haematobium endemic areas has shown high prevalence of bladder wall thickening, irregularities, and polyps which were usually more frequent and severe in children and in those excreting most ova. Obstructive uropathy was frequent in most studies. Chemotherapy usually rapidly resolved the bladder wall abnormalities. In some studies hydronephrosis and hydroureter were more persistent. Reversibility of chronic, stable lesions in adults remains unproven.

Fever in the returned traveler

Febrile infections can be fatal in travelers to tropical countries unless the patient seeks medical care in a timely manner and the physician takes the time and has the skill to make a rapid diagnosis and prescribe appropriate therapy. In addition to the usual febrile illnesses present in temperate climates, the patient may have an "exotic" infection, e.g., malaria, infectious hepatitis, enteric fever, or dengue fever. The potential causes of fever in travelers are extensive. This article provides practical clues to assist the physician in making the correct diagnosis--by using exposure information, symptoms and signs, and concomitant symptom complexes.

Tuberculous peritonitis in Egypt: the value of laparoscopy in diagnosis

Abdominal laparoscopy was performed on 200 patients with undiagnosed ascites. It was unsuccessful in one patient with tuberculous peritonitis because of extensive adhesions. A presumptive diagnosis of tuberculous peritonitis based on clinical findings and peritoneal tubercles or adhesions visualized during laparoscopy was made in 90 of these patients. The diagnosis was confirmed in 88 by histopathology, bacteriology, or therapeutic response. Two of the 109 remaining patients who had other presumptive diagnoses made during laparoscopy were eventually confirmed to be cases of tuberculous peritonitis. Of 91 patients with tuberculous peritonitis included in this series, 79% were females, with the majority (79%) of them being of child-bearing age. Half had been ill for longer than one month. The most frequent complaints were abdominal pain, fever, anorexia, night sweats, abdominal swelling, and weight loss. Ascites, fever, wasting, pallor, and abdominal tenderness were common findings. Ultrasonography demonstrated ascites in all patients who underwent this procedure; 21% also had adhesions. Pleural effusion was present in 15% and pulmonary tuberculosis was detected in only two patients. Biopsy samples taken during laparoscopy showed that 60% had noncaseous granulomas and 33% had caseous granulomas. Mycobacterium tuberculosis was detected in 77%, with guinea pig inoculation having the highest sensitivity, followed by culture, and lastly by acid-fast smear. Mycobacterium tuberculosis was isolated more easily from biopsy samples than from ascitic fluid. Nine of 20 M. tuberculosis isolates that were identified as to species were M. bovis. Tuberculous peritonitis, a frequent cause of febrile ascites in Egyptian women, was easily diagnosed by histopathologic and bacteriologic studies of biopsy samples taken at laparoscopy. All patients responded rapidly to antituberculosis therapy.

Efficacy of hepatitis B vaccination in primary school children from a village endemic for Schistosoma mansoni

To determine whether chronic Schistosoma mansoni infection interferes with hepatitis B virus (HBV) immunization, 308 schoolchildren aged 6-12 years with no evidence of prior HBV infection (156 with active schistosomiasis) were vaccinated with three 5-micrograms injections of recombinant DNA-derived HBV vaccine. The vaccine was given in the deltoid muscle at time 0 and 1 and 7 months later. All vaccinees were examined 1 and 3 years after vaccination for quantitative antibody to hepatitis B surface antigen (anti-HBs). Seroconversion was detected in 284 vaccinated children (92%), of whom 271 had a good (51-300 mIU/mL) or excellent (greater than 300 mIU/mL) anti-HBs response. Sixteen other children (5%) had evidence of natural HBV infection (antibody to hepatitis B core antigen). Of those with good or excellent response, 99% retained high antibody titers for 3 years. Response was not influenced by S. mansoni infection. Hepatomegaly and splenomegaly were associated with reduced vaccine response.

Ultrasonographic changes of the liver in Schistosoma haematobium infection

Abdominal ultrasonographic examination was performed in 61 hospitalized patients with chronic liver diseases and 253 school children from a village endemic for Schistosoma haematobium and were compared with 142 urban children without exposure to Schistosoma. The prevalence of ultrasound-detectable hepatomegaly and splenomegaly and the degree of periportal fibrosis was compared between those with and without S. haematobium infection. Among 13 patients with biopsy-proven schistosomal hepatic fibrosis, three with coarse changes secondary to S. mansoni infection showed grade III periportal fibrosis, while 10 patients with fine schistosomal hepatic fibrosis due to S. haematobium had borderline (two) or grade I (eight) changes. Ultrasound evidence of periportal fibrosis was not detected in patients with hepatic cirrhosis, chronic active hepatitis, or fatty infiltration. However, three of 14 patients with chronic persistent hepatitis had grade I periportal fibrosis and two had borderline changes. The frequency of ultrasound-detected hepatomegaly and splenomegaly was greater among rural S. haematobium-infected children (35.2% and 22.4%, respectively) than among noninfected rural (21.1% and 13.3%) and urban (16.9% and 4.9%) children. Also, the frequency of grade I periportal fibrosis was significantly greater (P less than 0.01) in S. haematobium-infected children (22.4%) than in noninfected rural (11.7%) and urban (0.7%) children. No patients with S. haematobium infections, either in the hospital or the village, had grade II or III periportal fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)