Infectivity to hosts of the endogenous stages of chicken and murine Cryptosporidium.

Five groups of 4 mice each were inoculated with 10(6) Cryptosporidium muris oocysts. They were necropsied on days 2, 4, 6, 8 and 10. The stomach mucosa from each group were made into 10% suspension in physiological saline and were orally inoculated to 2 mice each. Recipients given suspension from infected mice on day 6, 8 and 10 shed oocysts from 6, 9 and 6, respectively. Similarly, White Leghorn received 10(6) Cryptosporidium sp. oocysts were killed daily between 1 and 6 days. Recipients given bursa of Fabricius or caecum of donor birds on days 4, 5 and 6 shed oocysts. The endogenous stages of murine and chicken Cryptosporidium were able to infect the appropriate host.