ShiStoSomiaSiS and hCV infeCtionS –do they haVe a role in the pathogeneSiS of Some oral pathologiCal leSionS? ABSTRACT Schistosomiasis is the most common parasitic infection in Egypt. HCV-antibodies have been reported in a high percentage of Egyptian adults suffering from schistosomiasis and without a history of blood transfusion. This study was performed on patients seeking treatment in the Maxillo facial departments, Faculty of Dentistry, Alexandria University in one year period (from 2008 to 2009). All presented with neoplastic or non neoplastic head and neck lesions. Patients are positively infected with shistosomiasis and HCV infection. Clinical, histopathological, Salivary and tissue PCR analysis were applied for all cases. Positive correlation was found between HCV infection and oral Lichen planus, oral squamous cell carcinoma and malignant Lymphoma .This means that both Shistosomiasis and HCV infection could play a role in the pathogenesis of some extrahepatic oral lesions whether through direct or indirect route. Sana. F. Abouelazm * ; Amany N.Abd El-Latif ** ; Hala H.Yassyn *** and Sara M. Abdelhamid **** * Professor of Oral Pathology, Faculty of Dentistry of Alexandria ** Lecturer of Oral Pathology Faculty of Dentistry Pharos University in Alexandria *** Associate Professor of Oral Medicine Faculty of Dentistry Pharos University in Alexandria **** Lecturer of Pharmacology & Immunology , Faculty of Pharmacy Pharos University in Alexandria Vol. 55, 1:15, April, 2009 introdUCtion Infection with HCV has been identiied as the major cause of non-A, non-B hepatitis and cirrho- sis (1,2) . Recent studies (3-4) have indicated that in Egypt the sero-prevalence of anti-HCV antibodies in blood donors is more than ten times greater than in Western populations. Moreover, preliminary data from Egyptians living abroad (5) suggest that the prevalent HCV genotype in Egypt differs from elsewhere. A frequent association between HCV antibodies and schistosomiasis in Egypt has recent- ly been reported (6-7) Hepatitis C infection not only causes chronic liver diseases but also shows extrahepatic manifestations and immunological disorders. (8,9) The prevalence of these extrahepatic diseases is not known with certainty but there are studies that have suggested that HCV is involved in non-hepatic oral (81)