Thesis (Ph.D.) - Cairo University - Faculty of Medicine - Department of Parasitology

Cryptosporidium spp. are coccidian protozoans that cause cryptosporidiosis, a parasitic disease of the mammalian intestinal tract. Cryptosporidium parvum is considered to be the most important waterborne pathogen in developing countries, it is among the most relevant parasitic enteric agents in human and veterinary medicine. It is resistant to all practical levels of chlorination and it is an obligate intracellular pathogen. It has been the cause of multiple diarrhea outbreaks in developed and developing countries.The present work was carried out to evaluate the pathological, immuno-histochemical and molecular changes in the ileocecal region induced by chronic irritation with different inoculum sizes of cryptosporidium (50,500 occysts) in immunocompetent and immunosuppressed mice. The mice were euthanized at different dates starting from 14, 21, 36, 45, 57 till day 64 to study these transformations. Histopathological examination of the ileocecal region revealed neoplastic changes in the form of dysplasia, polypoid structures, architectural distortion, glandular crowding, marked cellular atypia, exophytic adenomatous polypi, intramuscular adenocarcinoma and marked nuclear anaplasia. Immunohistochemical analysis of the K-ras showed alterations in K-ras expression that indicates presence of neoplastic changes in the ileocecal region which was graded as: Nil, Mild, Moderate and Severe. Molecular evaluation of primer 1 (TLR2), primer 2 (TLR4) and primer 3 (pla2g2a) genes expression showed upregulation of the primers{u2019} genes in the infected mice

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