الفهرس 
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Abstract
Human fasciolosis was very sporadic until the last few decades when many cases and outbreaks were reported. It has now become an important emerging food-borne trematode infection of increasing concern. The largest numbers of affected people have been reported from Bolivia, China, Ecuador, Egypt, France, Islamic Republic of Iran, Peru and Portugal. The present study was a trial to confirm the presence of the two species of Fasciola in Egypt and to define the species incriminated in human fasciolosis. Proper identification and characterization of Fasciola species present in Egypt is very important to build up a powerful strategy of control, which may be applicable to other countries. 1st. Study on animal fasciolosis: A.1. Morphological and morphoanatomical data: From the general shape, adult flukes could be classified into typical F. gigantica, typical F. hepatica and unidentified flukes that may be misdiagnosed or considered as intermediate forms. After comprehensive literature review and major experimentation, reliable taxonomic criteria were established to differentiate between the two species and the probability of the presence of intermediate forms among the studied samples was excluded. According to the present study, typical F. gigantica was differentiated morphologically from typical F. hepatica on account of its elongated shape, less breadth, less developed shoulders and larger ventral sucker. Also, the posterior half of the body of F. hepatica gradually narrowed presenting a more or less V-shaped outline, while in F. gigantica the narrowing only commenced at a very short distance from the tail end. Morphoanatomically, F. gigantica was differentiated from F. hepatica based on shape of the ovary; shape, size and location of the testes; branching system of the intestinal caeca and shape of the cuticular scales of the dorsal side of the acetabular region. A.2. Morphometric data: The morphometric study carried out to establish reliable taxonomic criteria that can be applied on fresh specimens without affecting their viability or at least without affecting the nature of their proteins. In each of F. gigantica and F. hepatica there was a significant positive correlation between fluke length and each of fluke breadth, testes length and length of the area behind the testes. These correlations may indicate that viable fluke muscle contraction and relaxation does not affect significantly parameters used for speciation if measured in a proper way. The present study revealed that for each Fasciola species, flukes isolated from buffalo hosts were significantly longer and broader than those isolated from cattle hosts. Moreover, the length of testes and the length of the area behind the testes were significantly longer in flukes isolated from buffalo hosts than those isolated from cattle hosts. These morphometric differences did not affect the morphometric indices used for identification of the fluke species. A.3. Experimental snail infection: According to the results of the present study, F. gigantica was better adapted to L. cailliaudi snails than F. hepatica. A.4. The electrophoretic study: IEF in ultrathin-layer polyacrylamide gel containing 3 carrier ampholines was carried out in order to study the protein characteristics of F. gigantica and F. hepatica individuals from buffalo and cattle as well as host liver. The differences in banding patterns between the soluble proteins of F. gigantica and F. hepatica worms were so obvious that no confusion may arise. The host liver samples showed that the patterns contain some of the banding characteristics for F. gigantica and F. hepatica. The soluble protein banding patterns of host liver had more protein bands than F. gigantica and F. hepatica. The presence of shared banding characteristics between Fasciola spp. and its vertebrate host liver may be due to the presence of shared antigens. By comparing the results of the narrow pH range gradient (pH range of 5-8) with those of the wide pH range gradient (pH range of 3.5-10), it was found that the narrow pH range revealed better banding patterns compared with the wide pH range. Accordingly, it could be concluded that the wide pH range may be used first to explore the presence of any difference in banding patterns, then the narrow range(s) may be used to study these differences in details as recommended before. According to the present morphological, morphometric and electrophoretic studies: 1. IEF has a very good resolution and can be used as a powerful tool for differentiation between Fasciola species even when the classical morphological and morphometric methods may fail. 2. Both F. gigantica and F. hepatica are present in the Nile Valley of Egypt. Also, no intermediate forms resulted from hybridization between the two species of Fasciola was found in the present study, which may exclude the possibility of finding such forms in the studied area. B. Study on human fasciolosis: A total of 51 cases (15 males and 36 females) with confirmed chronic human fasciolosis were participated in the present work. They were diagnosed coproscopically through the field activities carried out by the Parasitology Department, Medical Research Institute, in Abis villages. B.1. Egg count: According to the present data: 1. Human cases tended to pass low epg more frequent than high epg. The range of the egg count in the studied human cases was 12-936 epg, with an arithmetic mean of 95 (±141.2) epg and a geometric mean of 55 epg. 2. The difference in egg counts between the two age groups was non-significant. 3. The differences in egg counts between male and female cases of the two age groups were non-significant. B.2. Egg measurements: One of the goals of the present study concerning animal hosts was to establish a gold standard to differentiate between eggs of the Egyptian strains of each of F. gigantica and F. hepatica, and to use it for identification of the species incriminated in human fasciolosis. The following results were obtained: 1. The size of eggs obtained from human samples (139 X 80 ?m) favored the diagnosis of F. hepatica (134 X 79 ?m). 2. A significant positive correlation was found between the measurements (length and breadth) of Fasciola eggs isolated from human stool. This correlation was similar to that of the measurements of F. hepatica eggs from animal origin. 3. The eggs isolated from the age group below 15 years were significantly larger than those of the age group equal to or above 15 years. This may indicate that the age group below 15 years is more suitable than the age group equal to or above 15 years to fluke infection. 4. The differences in egg length and breadth between male and female cases of the two age groups were non-significant. 5. Positive correlation between the egg count and the egg measurements was found. B.3. Experimental snail infection: It was found in the present study that Fasciola spp. eggs isolated from human feces failed to infect L. cailliaudi snails. This may be an indicator that strengthens the assumption of F. hepatica being the species incriminated in human infection in Abis area. From all the above-mentioned results, it could be concluded that the species incriminated in human fasciolosis in Abis area and may be in the Nile Valley of Egypt is F. hepatica.^leng