الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Schistosomiasis is one of the major health problems in Egypt. At the ’pulation level it affects man power and health, leading to severe morbid and mortality among our population. Economically millions of Egyptian unds are directed to disease control. The diagnosis of schistosomiasis is still mainly based on direct parasi ,gical techniques, through detection of parasite eggs in the excreta of However limitations in the sensitivities and specificities can not be overcomed. Repeated stool examinations are to get reliable results of the intensity of infection ause of day- to day fluctuation in the egg excretion. Only a small perce e of deposited eggs are excreted with faeces and urine. Many cases be easily missed, as in acute infection, chronic infection with intensive SIS and also in sexually imbalanced infection. Several studies in different institutions all over the world have been cted to serological diagnosis of schistosomiasis as an alternative to t methods. Numerous techniques have been described, the variability such techniques is an indication that a satisfactory test regarding itivity , specificity and field applicability has not yet achieved. Tests aimed at antibody detection have not shown to be an accepta e alternative for the commonly applied parasitological techniques. This especially in endemic areas where the antibody levels remain high after cessful eradication of infection. Moreover antibody detection does not ’ye sufficient information about intensity of infection which is considered good parameter of disease morbidity. Diagnostic tests detecting ’culating schistosome antigens are expected to indicate active infection ~ assess worm burden. Since secretory and excretory antigens are eased by living worms, they should be expected as a good candidates ich would allow the assessment of schistosomicide and environmental trol programs. Review of seroepidemiological studies indicate that they all were ,igned to achieve one or more of the following objectives: 1) detection of le infection, 2) detection of low excreter, 3) assessment of morbidity, 4) dying the impact of treatment and 5) determination of resistant state lich will be of great help in vaccine development researches. OUT study was designed to answer the following question ”can CAA ction in sera of Schistosoma mansoni infected Egyptian patients used .” ~iagnosis as well as in cure assessment after praziquantel therapy?”. We constructed a cross-sectional cohort study with longitudinal lW-UP of treated infected cases. The initial cohort consisted of 257 men age to 25 years old, randomly selected from a military camp in Alexandria, Egypt. Three 40 mg stool samples and 10 m!. urine samples were examined for every individual before treatment. Stools were examined using the Kato thick smear technique, which served as a gold ’-!Iandard for infection. Urine samples were tested using Nuclepore filtration technique. Infected individuals were. treated with 40 mg\Kg ~raziquante1. Blood samples were obtained from the entire cohort at inception for detection of CAA using monoc1onal antibody 120-1 B-1 OA in a lindwich ELISA technique. Blood and stool samples were collected and ~sted after praziquantel therapy at weeks 2,4,8,16 and 24, for assessment of cure, 110 Kato negative cases from both endemiC and non-endemic lTeas were included in this study which are served as negative control. As neither CAA nor eggs per gram of stool were normally distributed Ion parametric statistical analysis Spearman’ s rank of correlation were ,- ,ed. Sensitivity and specificity of ELISA was determined. Kato thick ear results served as the gold standard with a CAA titre ~4 defined as a ,sitive index. The proportion of all individuals who had a positive Kato ult with elevated CAA titers- was defined as the sensitivity of tbe test. ,e proportion of all individuals with 3 negative Kato results with titer <4 as defined as the test specificity. After treatment and according to the wresults of Fisher exact test, cases at the two weeks visit were not included in the study to avoid persons who are excreting eggs despite effective ilierapy, as well as those with persisting antigenmia. For further analysis of the test receiver operating characteristics (ROC) curve were generated Dr varying the cut-off point for the positive test. The probability of ~~sitive Kato in relation to CAA titer was examined by likelihood ratios. The results revealed that out of the total 257 individuals, 147 cases Eet criteria for S. mansoni infection (57 ). The range of epg was 12 to 1B2, arithematic mean of 247 epg and geometric mean of 137 epg. CAA as detected in 117 cases (sensitivity = 0.796 ). None of the cases with 1 S. mansoni eggs had a titer ~4 (specificity =1.0). , CAA titer and epg As the CAA titer increased, so did the ornetric mean of epg. Spearman’s rank of correlation was 0.532 ( P< ,881). The significance of Spearman’s rank was related to the intensity the infection as measured by epg. Test performance to evaluate cure Cure with praziquantel inistration was achieved in 92 of cases one month after therapy There was significant reduction in the geometric means of CAA and epg at each follow up interval. ROC Curve Analysis The ROC curve shows an area of 0.82, which indicates an excellent discriminating ability. The optimal cut-off point was 4. The Liklehood ratio Because the specificity is near perfect before Ireatment , the liklehood ratios all approaches infinity . After treatment, Je liklehood ratios range from 12 at a titer of less than 16 to reach !,rmity at a titer of 128 and onward. The data demonstrate an extra ordinary high specificity of the te s t which is simple, accessible for both epidemiological surveys as well as dia !nostical1y. However, the sensitivity has to be improved especially for low excreter. Such improvement could entail the use of molecular biology techniques such as immuno-PCR which was reporteQ to be 105 more lensitive than indirect ELISA. The use of recombinant DNA technology for identification and purification of schistosomal antigens which can be used as a candidate for immunodiagnosis. ^leng