MODEL OF INFECTION - CRYPTOSPORIDIUM-PARVUM BILIARY-TRACT INFECTION IN ADULT IMMUNOCOMPETENT AND IMMUNOSUPPRESSED MICE

Biliary tract infection by Cryptosporidium parvum is a frequent compli cation of intestinal cryptosporidiosis in immunosuppressed patients. A lthough biliary tract infection can be produced in immunosuppressed mo dels as a late complication of intestinal infection, there is no infec tion model in immunocompetent animals. A murine model of biliary tract cryptosporidiosis was developed by direct intra-gall bladder injectio n of C. parvum oocysts. In adult immunocompetent mice, intracellular p arasitic stages were detected in the epithelium of the common bile duc t in all animals on day 7 post-inoculation (p.i.). These findings were associated with a strong inflammatory reaction. Infection was cleared between days 14 and 21 p.i. All animals developed significant levels of specific serum and bile IgG, IgA and IgM. Dexamethasone treatment r esulted in the inability of animals to eradicate the parasite and the establishment of ileal parasitism. This model can be used to study the immunological mechanisms involved in the control of biliary cryptospo ridiosis.