It has been recognized recently that human cryptosporidiosis is usually caused by Cryptosporidium parvum genotype I ("human" C. parvum), which is not found in animals. Compared to C. parvum genotype II, little is known of the biology of invasion of the human-restricted C. parvum genotype I. The aims of the present study were (i) to explore and compare with genotype II the pathogenesis of C. par...

A murine model of implanted CNS neoplasia was used to study a new form of brain tumor immunotherapy with intralesional Corynebacterium parvum (C. parvum). Assessment of treatment protocols has been limited by the inability to assess, noninvasively, tumor burden and/or the inflammatory reaction induced in the murine brain by treatment with C. parvum. This study demonstrates that contrast-enhance...

We studied the growth and feeding response of the ciliate Euplotes affinis when exposed to algal cultures of Prymnesium parvum and Rhodomonas cf. baltica as monocultures or as mixtures. Cultures of P. parvum grown under nutrient-limited (N or P) or nutrient-sufficient conditions were tested for toxicity against E. affinis. Ciliates grew well when fed R. cf. baltica, but avoided grazing on monoc...

Ureaplasma parvum (U. parvum) is gaining recognition as an important pathogen for chorioamnionitis and preterm premature rupture of membranes. We aimed to investigate the roles of progesterone (P4) and a novel progesterone receptor, progesterone receptor membrane component 1 (PGRMC1), in the response of fetal membranes to U. parvum. Fetal membrane cells (amnion, chorion and decidua) were isolat...

The aim of this study was to produce a conjugate containing anti-Cryptosporidium parvum polyclonal antibodies and standardize a Direct Immunofluorescence Assay (DIF) for detecting C. parvum oocysts in fecal samples from calves. In order to obtain anti-C. parvum polyclonal antibodies, two New Zealand rabbits were immunized with a purified solution of C. parvum oocysts and Freund’s adjuvant. Puri...

The protozoan parasite Cryptosporidium parvum invades intestinal epithelial cells and can cause life-threatening diarrhea in immunocompromised individuals. Despite the clinical importance of this organism, much remains to be learned about the pathogenesis of C. parvum-induced diarrhea. To explore the role of the intestinal inflammatory response in C. parvum disease, using C. parvum oocysts we i...

Cryptosporidium is a major cause of severe diarrhea, especially in malnourished children. Using a murine model of C. parvum oocyst challenge that recapitulates clinical features of severe cryptosporidiosis during malnutrition, we interrogated the effect of protein malnutrition (PM) on primary and secondary responses to C. parvum challenge, and tested the differential ability of mucosal priming ...

Severe experimental infections with Cryptosporidium parvum have been reported in immunocompromised animals such as SCID mice (mice without functional T cells and B cells). In a C. parvum infection with 1 x 10(6) oocysts/mouse in SCID beige (SCIDbg) mice (SCID mice lacking functional NK cells), oocyst shedding was first demonstrated 18 days after infection. However, shedding was shown as early a...

The purpose of this study was to determine whether gamma-irradiated Cryptosporidium parvum oocysts could elicit protective immunity against cryptosporidiosis in dairy calves. Cryptosporidium parvum Iowa strain oocysts (1 x 10(6) per inoculation) were exposed to various levels of gamma irradiation (350-500 Gy) and inoculated into 1-day-old dairy calves. The calves were examined daily for clinica...

Cryptosporidium parvum is an obligate intracellular protozoan capable of causing severe diarrheal disease in a wide variety of mammals, including humans. C. parvum infection has been associated with induction of apoptosis in exposed epithelial cells, and we now demonstrate that apoptosis is restricted to a subset of cells actively infected with C. parvum. Approximately 20% of the infected cells...