마우스, 랫트, 기니픽에 대한 cryptosporidium parvum의 실험적 감염

Experimental infection of mice, rats and guinea pigs with crytosporidium parvum

This study was performed to observe the morphological characteristics of the parasite Cryptosporidium isolated from the infected mice in Korea and to choose the laboratory animals which is suitable to the research for the Cryptosporidium. Oocyst obtained from fresh feces of mice were sporulated, four elongate sporozoites and residual body present within each oocyst and wall composed of 2-layers. Oocyst were spherical, 4.98±0.49×4.71±0.6㎛(mean±S.D.)in size and shape index (length/width ratio) 1.06±0.04, which is considered to be C. parvum (VRI-CN9l) morphologically. When mice, rats and guinea pigs were infected experimentally, the infection rates were 92.8%, 81.6% and 40.0%, respectively. Mice were significantly more susceptible than others (P＜0.05). Oocysts were discharged in feces on post-inoculation day 4 and infection rates were dependent on the ages of animals. Infection and proliferation rates of oocysts were not dependent on the inoculated dosages. It is considered that the infection dynamics of C. parvum be more closely related to the ages of animals rather than the dosages of inoculation. The overall results showed that the most suitable laboratory animal for C. parvum would be the mice at the age of less than 21 days or neonatal rats.