Abstract. Health questionnaires and parasitologic examinations of urine and stool were evaluated from a stratified random sample of 89,180 individuals from 17,172 households in 251 rural communities in 9 governorates of Egypt to investigate the prevalence of, risk factors for, and changing pattern of infection with Schistosoma sp. in Egypt. A subset, every fifth household, or 18,600 subjects, had physical and ultrasound examinations to investigate the prevalence of and risk factors for morbidity. Prevalence of S. haematobium in 4 governorates in Upper Egypt in which it is endemic ranged from 4.8% to 13.7% and averaged 7.8%. The geometric mean egg count (GMEC) ranged from 7.0 to 10.0 ova/ 10 ml of urine and averaged 8.1. Age stratified prevalence of infection peaked at 15.7% in the 10-14-year-old age group and decreased to 3.5-5.5% in all groups more than 25 years of age. Age-stratified intensity of infection peaked at approximately 10.0 ova/10 ml of urine in the 5-14-year-old age groups and was about half that in all groups more than 25 years of age. Males had higher infection rates and ova counts than females in all age groups. Schistosoma mansoni was rare in Upper Egypt, being consequential in only Fayoum, which had a prevalence of 4.3% and an average intensity of infection of 44.0 ova/g of stool. Risk factors for S. haematobium infection were male gender, an age Ͻ21 years old, living in smaller communities, exposures to canal water; a history of, or treatment for, schistosomiasis, a history of burning micturition or blood in the urine, and reagent strip-detected hematuria or proteinuria. The more severe grades (II and III) of ultrasonography-detected periportal fibrosis (PPF) were rare (15 of 906) in these schistosomiasis haematobia-endemic governorates. Risk factors for morbidity (ultrasonography-detected urinary bladder wall lesions and/or obstructive uropathy) were similar to those for infection, with the exception that risk progressively increased with age. Subjects with active S. haematobium infections were 3 times as likely as those without active S. haematobium infections to have urinary tract morbidity. The prevalence of S. mansoni in 5 governorates in Lower Egypt, where it is endemic, ranged from 17.5% to 42.9% and averaged 36.4%. The GMEC ranged from 62.6 to 93.3 eggs/g of stool and averaged 81.3. Age-stratified prevalence of infection peaked at 48.3% in the 15-19-year-old age group, but averaged 35-45% in all groups more than 10 years of age. The intensity of infection was highest in the 10-14-year-old age group, and showed a range of 70-85 eggs/g of stool in those Ն5 years of age. Males had higher infection rates and ova counts than females in all age groups. Schistosoma haematobium was rare in these governorates; Ismailia (1.8%) had the highest infection rate. Risk factors for S. mansoni were male gender, an age Ͼ10 years old, living in smaller communities, exposures to canal water, a history of, or treatment for, schistosomiasis or blood in the stool, detection of splenomegaly by either physical...

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Risk factors, prevalence, and intensity of infection with Schistosoma sp. and prevalence and magnitude of morbidity caused by schistosomiasis was assessed in a stratified random sample of 16,433 subjects from 2,409 households in 33 rural communities in Minya Governorate, Egypt. The prevalence of S. haematobium ranged from 1.9% to 32.7% among the communities and averaged 8.9%. The average intensity of infection was a geometric mean egg count (GMEC) of 8.5 per 10 ml of urine and ranged from 1.6 to 30.9. Prevalence was maximum (18-20%) in those 10-20 years of age and higher in males than in females. Intensity of infection followed the same pattern. Infection with S. mansoni was present almost exclusively in a single village, confirming spread of this species up the Nile River and its focality in Minya. Risk factors for S. haematobium infection were an age from 11 to 20; male gender; males bathing in, women washing clothing or utensils in, and children swimming or playing in canals; and a history of, or treatment for, schistosomiasis. Recent history of burning micturition was associated with infection in children but not in adults, while a history of blood in urine correlated with S. haematobium infection in both age groups. Reagent strip-detected hematuria and proteinuria were highly associated, particularly in children, with S. haematobium infection. The presence of hepatomegaly or splenomegaly on physical examination was not associated with S. haematobium ova in the urine. Hepatomegaly, as measured by ultrasonography in the midclavicular line or the midsternal line, or ultrasonography-detected splenomegaly were not present more frequently in infected subjects than in uninfected subjects. Schistosoma ova were not detected more frequently in urine of subjects with ultrasonography-detected periportal fibrosis than in the urine from subjects without this finding. Ultrasonography-detected urinary bladder wall lesions were detected in only 6 (0.3%) subjects and obstructive uropathy was observed in 54 (2.7%) subjects. The absence of an association between prevalence of urinary tract morbidity and S. haematobium infections was surprising. Two possible explanations are 1) that repeated chemotherapy has reduced the prevalence of urinary tract morbidity and 2) that morbidity was not being detected by the ultrasonographic operators.

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Neural networks constitute a relatively new, radically different approach to the interpretation and recognition of subtle diagnostic patterns in multivariate data. In this study the use of neural networks with a single serum sample for rapid real-time recognition of recent toxoplasmic infection was investigated. A neural-network model was implemented on the basis of data obtained by four serological methods--dye test, indirect fluorescence assay, indirect hemagglutination assay, and IgM immunosorbent agglutination assay--and was "trained" to extract features of acute infection by application to an analysis of 65 immunocompetent patients, 10 of whom were in fact acutely infected. The trained model correctly classified all 10 cases of acute infection. On its application to 61 additional infected patients, this method correctly identified seven cases as potentially acute. Our study shows that neural networks can discern diagnostic patterns from variables that individually have limited utility in the diagnosis of acute toxoplasmosis.