Chronic Cryptosporidium parvum Infections in Congenitally Immunodeficient SCID and Nude Mice

Abstract

Severe combined immune deficient (SCID) and athymic National Institutes of Health (NIH)-III (bg/nu/xid) mice were evaluated for susceptibility to Cryptosporidium parvum infections as neonates and as adults after challenge with inocula of 5 x 10(4) and 1 x 10(6) oocysts/mouse, respectively. SCID and NIH-III nude mice developed chronic infections that persisted over 12 weeks. Cryptosporidial organisms were observed in the small and large intestines of all mice. Colonization of the gallbladder and hepatobiliary duct epithelium occurred in a majority of the NIH-III nude mice and a smaller number of the SCID mice. Severe infections in both mouse strains were associated with clinical deterioration followed by death. Signs in these mice included dehydration, icterus, and emaciation. Deaths apparently resulted from hepatic dysfunction. Control mice experienced transient infections with no clinical signs. Immunodeficient mice should prove useful in studies of disease pathogenesis and in evaluating potential anticryptosporidial agents.

Development of Cryptosporidium parvum-Induced Gastrointestinal Neoplasia in Severe Combined Immunodeficiency (SCID) Mice: Severity of Lesions Is Correlated with Infection Intensity

“…25 These changes, classified as low-grade dysplasia, 25 are consistent with our results. Interestingly, similar histologic findings (especially Figure 3 in Mead and others 23 ) were associated with chronic C. parvum infection in NIH-III nu/nu mice. 23 Despite the scarcity of information about links between human cryptosporidiosis and digestive neoplasia, some previous data suggested a possible causal association.…”

“…Interestingly, similar histologic findings (especially Figure 3 in Mead and others 23 ) were associated with chronic C. parvum infection in NIH-III nu/nu mice. 23 Despite the scarcity of information about links between human cryptosporidiosis and digestive neoplasia, some previous data suggested a possible causal association. An epidemiologic study of 55 patients with colorectal cancer and before chemotherapy, reported 18% of cryptosporidiosis prevalence.…”

“…22 Sequestration of the parasites out of the intestine and into other sites could also explain a diminished detection of Cryptosporidium oocysts in the faeces. 23 However, in our study, mice infected with 10 8 oocysts showed no more evidence of extra-intestinal parasites or more clinical signs than mice in other groups ( Table 1 ).…”

A severe combined immunodeficient (SCID) mouse model for infection with Entamoeba histolytica.

“…SCID mice have intact macrophage and NK cellmediated immunity (5,6). SCID mouse models have proved useful in studies of resistance to a number of viral (7)(8)(9), bacterial (10,11), helminth (12), and protozoan pathogens (13,14). We report here the establishment of a SCID mouse model for amebic liver abscess, and the use of this model to demonstrate that immune serum protects against visceral E. histolytica infection.…”

New species of Cryptosporidium Tyzzer, 1907 (Apicomplexa) from amphibian host: morphology, biology and phylogeny

“…Negative results of experiments support our conclusion that C. fragile is a separate species. Although the SCID mice are known to be a suitable model for intestinal and gastric cryptosporidiosis (Mead et al 1991, Lindsay et al 2000, they remained negative after inoculation with C. fragile indicating its inability to affect mammalian hosts. We further evaluated the host specificity of C. fragile in an array of frogs and tadpoles.…”