Development of Patent Infection in Immunosuppressed C57BL/6 Mice with a Single Cryptosporidium meleagridis Oocyst

• Published in: The Journal of parasitology Vol. 89; no. 3; pp. 620 - 622
• Main Authors: Huang, Kehe, Akiyoshi, Donna E, Feng, Xiaochuan, Tzipori, Saul
• Format: Journal Article
• Language: English
• Published: United States American Society of Parasitologists 01-06-2003; Allen Press Inc
• Subjects: animal models; Animals; avian cryptosporidiosis; Cryptosporidiosis; Cryptosporidiosis - immunology; Cryptosporidium; Cryptosporidium - genetics; Cryptosporidium - immunology; Cryptosporidium - physiology; Cryptosporidium meleagridis; Dexamethasone; disease course; Disease Models, Animal; Dosage; dose response; Drinking water; Epidemics; excretion; Experiments; Feces; Feces - parasitology; Female; Genotype; Genotype & phenotype; Genotypes; Humans; Immunocompromised Host; Immunosuppression; immunosuppression (physiological); infection; Infections; Laboratories; Mammals; Memory interference; Mice; Mice, Inbred C57BL; Microscopy; oocyst shedding; Oocysts; Parasitology; pathogen identification; pathogenesis; Pathogens; Polymerase Chain Reaction; Polymorphism; Polymorphism, Restriction Fragment Length; Protozoa; Random Allocation; RESEARCH NOTES; Restriction fragment length polymorphism; Shedding; United States > US; Wisconsin
• ISSN: 0022-3395; 1937-2345
• DOI: 10.1645/0022-3395(2003)089[0620:DOPIII]2.0.CO;2

The ability of Cryptosporidium meleagridis to produce patent infection was studied in adult C57BL/6 mice that were immunosuppressed with dexamethasone phosphate provided in the drinking water at a dosage of 16 μg/ml. Four days after the onset of immunosuppression, mice were orally challenged with 1, 3, 10, or 1,000 C. meleagridis TU1867 oocysts per mouse. The mice were monitored daily for 18 days postinoculation for oocyst shedding. Five of 10 mice given a single oocyst, 4 of 5 mice given 3 oocysts, and all 9 mice given either 10 or 1,000 oocysts became infected and began shedding oocysts 5–7 days after challenge and continued to shed oocysts until the end of the experiment on day 18 postchallenge. Approximately 107 oocysts per mouse per day were excreted, regardless of the challenge dose. Neither the noninfected, immunosuppressed nor the inoculated, nonimmunosuppressed control mice shed oocysts. The excreted oocysts were confirmed to be those of C. meleagridis by polymerase chain reaction–restriction fragment length polymorphism analysis. We show that C. meleagridis, originally classified as an avian pathogen but recently found in humans with cryptosporidiosis, can produce patent infection in mice infected with a single oocyst. Moreover, we demonstrate that the immunosuppressed C57BL/6 adult mouse is an ideal host for the propagation of clonal populations of C. meleagridis isolates for laboratory studies.