The epidemiology of schistosomiasis in Egypt: methods, training, and quality control of clinical and ultrasound examinations.

Morbidity due to schistosomiasis was evaluated in a subpopulation of 14,000 of the randomized sample in the Epidemiology 1, 2, 3 Project. It was measured by using a standardized questionnaire for obtaining medical history and symptoms and by performing standardized physical and ultrasound examinations. Reported herein are descriptions of the methods and training and quality control efforts made to insure that the morbidity data was reliable and consistent when collected by 7 different teams in 9 different governorates.

The epidemiology of schistosomiasis in Egypt: Menofia Governorate.

Health questionnaires and parasitologic examinations of urine and stool were performed upon a stratified random sample of 10,899 individuals from 1,537 households in 27 rural communities in Menofia Governorate in Egypt in 1992 to investigate the prevalence of, risk factors for, and changing pattern of infection with Schistosoma sp. in the governorate. A subset, every fifth household, or 1,480 subjects, had physical and ultrasound examinations to investigate prevalence of and risk factors for morbidity. The prevalence of S. mansoni ranged from 0.3% to 72.9% and averaged 28.5%. The geometric mean egg count was 81.3 eggs/gram of stool. Age-stratified prevalence and intensity of infection was 30-40% and 60-80 eggs/gram of stool from the age of 10 onward; males had higher infection rates and ova counts than females in all age groups > 10 years old. Schistosoma haematobium was rare, being consequential in only 1 community. Risk factors for S. mansoni infection were male gender; age > 10 years; living in smaller communities; exposures to canal water; history of or treatment for schistosomiasis or blood in the stool; detection of splenomegaly by either physical or ultrasound; and ultrasound-detected periportal fibrosis (PPF). The more severe grades of PPF were rarely (21 of 1,450 examinations) detected. Risk factors for morbidity, i.e., ultrasound-detected PPF, were similar to those for infection. Schistosoma mansoni has almost totally replaced S. haematobium in Menofia. The prevalence of S. mansoni in rural communities remains high and average intensities of infection are moderate. The association of morbidity with schistosomal infection was variable and is obviously markedly influenced by both the frequent use of antischistosomal chemotherapy in communities in Menofia and by the prevalence of complications from chronic viral hepatitis in the population: hepatomegaly did not correlate with infection; PPF and splenomegaly, however, were related to S. mansoni infection in both individuals and communities.

The epidemiology of schistosomiasis in Egypt: Fayoum Governorate.

Health questionnaires and parasitologic examinations of urine and stool were performed upon a stratified random sample of 7,710 individuals from 1,109 households in 21 rural communities in Fayoum Governorate, Egypt in 1992 to investigate the prevalence of, risk factors for, and changing pattern of, infection with Schistosoma sp. in the governorate. A subset, every fifth household, or 1,038 subjects, had physical and ultrasound examinations to investigate prevalence of, and risk factors for, morbidity. The prevalence of S. haematobium ranged from 0% to 27.1% and averaged 13.7%. The geometric mean egg count (GMEC) was 10.0 eggs/10 ml of urine. Age-stratified prevalence and intensity of infection were 18-25% and 10-15 eggs/10 ml of urine in those 5-25 years of age. Schistosoma mansoni were detected in inhabitants of 13 communities, but 78.5% of the infections were focally present in a group of 4 satellite hamlets around a single village. The overall prevalence of S. mansoni in the governorate was 4.3% and the GMEC was 44.0 ova/g of stool. Risk factors for infection with either species were male gender, an age <20 years, living in smaller communities, and exposures to canal water by males. Histories of burning micturation, blood in the urine, or prior schistosomiasis and reagent strip-detected hematuria and proteinuria were risks for S. haematobium, but not for S. mansoni. Both urinary tract and higher grades of hepatic morbidity were rare. Obstructive uropathy was present in 6.3% of the subjects and was more common in males and older people. Ultrasonography-detected bladder lesions were present in 5.2% and correlated with S. haematobium only in younger subjects and in those with hematuria and proteinuria. The prevalences of hepatomegaly, splenomegaly, and periportal fibrosis (PPF) were associated with each other and increased with age and in males. Ultrasonography-detected hepatomegaly and splenomegaly were weakly associated with S. mansoni infections only in children. The prevalence of PPF was greater in the 4 communities with >25% S. mansoni infection rates in comparison with the 17 other villages and ezbas. Transmission of S. mansoni is focally well established in Fayoum, which also has the highest prevalence of S. haematobium in the governorates surveyed by the Epidemiology 1, 2, 3 Project. However, both urinary tract and hepatic morbidity are relatively rare in the governorate. This probably results from the long-standing schistosomiasis control program in Fayoum, which suppressed intensity more than prevalence of infection, leading to less community morbidity.

Comparative study on different recent diagnostic and therapeutic regimens in acute typhoid fever.

Forty five positive blood culture acute typhoid cases were studied during a 2 years period (1997-1999) in Abbassia Fever hospital, Cairo, Egypt. Their ages ranged between 4-23 (12 +/- 2.5) years. Male: Female ratio was 1:1. Three of the 4 classical signs namely: toxic look (84%), bronchitic chest (47%), tumid tympanitic abdomen (84%) and just palpable receding spleen (69%) were found in almost all cases and offer a good bed side clinical diagnostic test. Blood picture revealed anaemia, within normal white blood count and thrombocytopenia. Liver function tests showed within normal total serum bilirubin, two or more folds increase of ALT and within normal serum alkaline phosphatase. Comparing the 3 tests, namely significant Widal titre (56%), modified Widal test (89%) and bright spleen (78%), it was found that modified Widal test is the most sensitive serological test. Ultrasonographic finding of bright spleen is an easy, safe, noninvasive and sensitive technique which is relatively cheap. Each of the 3 drugs in our study namely chloramphenicol, quinolones and ceftriaxone resulted in improvement of general condition, drop of fever, increase in haemoglobin, white blood count and platelet count. Also, there was a significant improvement of liver function tests by either of the 3 drugs. Ceftriaxone is the best drug from the clinical and laboratory points of view followed by quinolones in multidrug resistant (MDR) acute typhoid cases. Chloramphenicol is still the drug of choice in chloramphenicol sensitive salmonellae.

Parasitic infections presenting as prolonged fevers.

Over two successive years, out of 187 cases of fevers of undetermined origin (FUO) admitted to Abbassia and Embaba Fever Hospitals, 30 (16%) cases proved to be of parasitic origin. Ten within normal subjects were taken as controls. Complete blood picture, repeated stool examination, rectal snip by transparency technique, ELISA for specific IgM antibodies for S. mansoni, indirect haemagglutination test for S. mansoni, Fasciola, hydatid, amoebic liver abscess and toxoplasmosis, indirect fluorescent antibody test for toxoplasmosis and abdominal ultrasonography were performed whenever indicated. Cases comprised 8 (26%) acute S. mansoni, 7 (24%) acute fascioliasis, 3 (10%) hydatid cyst, 8 (26%) amoebic liver abscess, 2 (7%) toxoplasmoisis and 2 (7%) malaria cases. The clinical picture of acute S. mansoni and acute fascioliasis were similar in the form of prolonged fever, diarrhea, hepatomegaly and leucocytosis with high eosinophilia. Serology (ELISA and IHAT) was essential in differentiating them. Abdominal ultrasonography is an easy, sensitive, cheap, non-invasive technique aiding in the diagnosis of amoebic liver abscess, liver hydatid cysts and fascioliasis but again serology was essential in differenting them. Toxoplasmic lymphadenitis mimic the clinical picture of infectious mononucleosis. Serology (monospot test, IHAT, IFAT) clinched the diagnosis. Malaria cases presented atypically by gastrointestinal manifestations and hepatic affection. Diagnosis was by positive blood smears.

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.

Comparative study between paratyphoid A and typhoid fever cases.

Twenty eight positive blood culture paratyphoid A fever cases were studied. Forty two positive blood culture typhoid cases were taken as controls. Cases and controls were subjected to: 1) careful history, 2) thorough clinical examination, 3) two blood cultures for salmonella, 4) Widal agglutination test, 5) total and differential white blood count, 6) urine and stool cultures following therapy. There was no significant difference in the clinical picture between acute paratyphoid A fever and acute typhoid fever except the significant decrease of anorexia (57%), toxic look (54%), coated tongue (64%) in acute paratyphoid A cases when compared to acute typhoid cases. The prevalence of extraintestinal symptoms in paratyphoid A cases may mimic viral infections. Three of the 4 classical signs namely; toxic look (54%), bronchitic chest (50%), splenomegaly (72%) and tympanitis (64%) were good bed side suggestive clinical diagnostic aids in paratyphoid A cases. Blood culture was the cornerstone of diagnosis of paratyphoid A cases. In 6 (21%), only the second blood sample was positive stressing the value of multiple cultures. Significant Widal antibody titre was elicited in only about half (57%) of paratyphoid A cases which was significantly lower than typhoid cases (83%). Leucopenia was found in only 25% of paratyphoid A cases. Eosinopenia was constant and is considered as a diagnostic and prognostic aid. No correlation was elicited between either the height of antibody titre or the height of leucocytic count and the severity of illness. There was no significant difference in the response to therapy or the occurrence of complications between paratyphoid A cases and typhoid cases. Up to the current knowledge, this is the first report on comparative study between acute paratyphoid A fever and acute typhoid fever in Egypt from clinical, diagnostic, therapeutic and prognostic points of view.

Chloramphenicol drug failure in typhoid fever.

Two hundred positive blood culture typhoid patients admitted to Embaba Fever Hospital, Giza province, were subjected to: 1) Careful history and thorough clinical examination. 2) Complete blood picture. 3) Widal agglutination test. 4) Urine and stool cultures for Salmonellae. 5) To the isolates of the cultures, disk diffusion chloramphenicol susceptibility test, minimum inhibitory concentrations and chloramphenicol acetyl transferase test were performed. The dose of chloramphenicol was restricted to 50 mg per Kg body weight daily, whatever the route used; whether oral, rectal or intravenous. When fever did not drop up to 5 days or the patient presented with typhoid complications or the blood culture revealed resistant Salmonellae, quinolones or third generation, cephalosporins were administered. Measurement of the level of chloramphenicol in the blood was performed for every patient. Fifty (25%) patients were found to be resistant in vitro and in vivo to chloramphenicol. All their Salmonellae isolates were resistant to chloramphenicol, the mean zone size was 10 mm, the mean inhibitory concentration was 64 microgram per ml. and all were positive for chloramphenicol acetyl transferase. There was no significant difference in the serum level of chloramphenicol between susceptible and resistant groups to the drug. Results were interpreted and discussed.

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.

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.

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. 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.

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.

Ultrasound for detecting Schistosoma haematobium urinary tract complications: comparison with radiographic procedures.

Chronic infection with Schistosoma haematobium primarily causes urinary tract complications. These lesions are often silent or ignored and not detected until irreversible changes have occurred. However, early chemotherapy can prevent progression and usually reverse all but the more severe abnormalities. Recently, abdominal ultrasound has been shown to be an inexpensive, portable and safe means of detecting schistosomal morbidity. A prospective study was performed on 40 patients comparing abdominal radiography, excretory urography (IVP), cystoscopy and ultrasound to detect urinary tract morbidity due to S. haematobium infection. Ultrasound was as sensitive as an IVP in detecting bladder masses, hydronephrosis and renal stones. It detected hydroureter less frequently (sensitivity 62.5%) than an IVP but visualized this lesion and hydronephrosis in some patients with nonfunctioning kidneys. Ultrasound demonstrated bladder stones as well as an x-ray but it detected bladder wall calcification with less sensitivity (65%) and was much less sensitive (12.5%) for detecting ureteral stones.

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.

Schistosoma haematobium infection in Egyptian schoolchildren: demonstration of both hepatic and urinary tract morbidity by ultrasonography.

Parasitological, clinical and ultrasonographical studies were performed upon 422 schoolchildren aged 12-16 years living in a village in the Fayoum where Schistosoma haematobium, but not S. mansoni, was transmitted. Over half of the children gave a history of receiving praziquantel therapy during the preceding 2 years. Symptoms (e.g., haematuria, burning micturition), signs (e.g., hepatomegaly, splenomegaly) and urinary findings (e.g., haematuria, proteinuria) correlated better with the presence and intensity of S. haematobium infection after correcting for this variable. Renal obstructive lesions detected by ultrasound were 2 and 3 times as common in those with moderate and heavy infections as in those with no or light infections, and urinary bladder wall lesions were far more frequent in those with moderate and heavy infections. A mild grade of periportal fibrosis, hepatomegaly and splenomegaly were present in some children in all groups. However, the prevalence of splenomegaly correlated directly with the intensity of infection; liver lesions occurred much more frequently in children with infection or a history of treated infection than in non-infected children denying recent treatment; and no child had hepatomegaly or splenomegaly in the absence of periportal fibrosis.

A review of the literature on the use of ultrasonography in schistosomiasis with special reference to its use in field studies. 1. Schistosoma haematobium.

This review presents an outline of the pathology resulting from Schistosoma haematobium infections, and the ways in which the lesions 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 has the advantages that it is non-invasive, and is also relatively inexpensive and can be used under field conditions. Ultrasonography has already been used in a number of epidemiological studies in areas where S. haematobium is endemic. The method 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. The correlation of results obtained using ultrasound with the results of clinical, parasitological and other observations has been investigated in a number of studies, but many questions remain to be answered.

A review of the literature on the use of ultrasonography in schistosomiasis with special reference to its use in field studies. 2. Schistosoma mansoni.

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.

Grading of hepatic schistosomiasis by the use of ultrasonography.

Forty-three subjects with pure hepatic schistosomiasis having ultrasonographic assessment of periportal fibrosis were grouped according to the thickness of their portal tracts: grade I = 3-5 mm, grade II = greater than 5-7 mm, and grade III = greater than 7 mm. A history of hematemesis, blood transfusion, sclerotherapy, and lower limb edema correlated with the ultrasonographic grade of periportal fibrosis. With increasing grade, the average liver size was smaller and the average spleen size was larger, as determined by physical examination and by ultrasonography. Abnormalities in serum enzyme levels were more frequent in those with thicker portal tracts. Greater diameters of the portal and splenic veins and ultrasonographically detectable collateral blood vessels were associated with increasing thickness of portal tracts. The grade of endoscopically determined esophageal varices was highly correlated with the grade of periportal fibrosis. We concluded that this method of grading accurately reflects the hemodynamic changes and provides a good estimate of the clinical status of patients who have periportal fibrosis due to schistosomiasis mansoni. Where available, it should replace clinical grading based upon the liver and spleen size as detected by physical examination.

The value of ultrasonography in assessment of portal hypertension in hepatosplenic schistosomiasis.

Ultrasonography can reveal most of the manifestations of portal hypertension complicating hepatosplenic schistosomiasis. However, direct demonstration of gastroesophageal varices by ultrasonography is still very difficult. An attempt was done to correlate sonographic features of portal hypertension with the degree of fibrosis to screen patients having varices and predicting their chance of bleeding. The results obtained were found to be consistent with the esophagogastric endoscopy and with history of hematemesis. Four parameters were used, size of spleen, degree of periportal fibrosis, presence of collaterals and portal vein diameter. A pilot field survey was also done adopting the same principle.