Résumé
Cryptosporidiosis has a worldwide geographical and zoological distribution. Cryptosporidium baileyi oocysts were isolated from the bursa of Fabricius [BF] of 4 weeks-old of 100 broilers. Twenty five broiler chicks of 2 day old free from cryptosporidial infection were inoculated intratracheally at a dose of 1 x 10[6] chicks. Five chicks were sacrificed at 4[th], 8[th], 12[th], 16[th], and 20[th] day postinoculation. Selected tissues from bursa of Fabricius, cloaca, colon, caeci and tracheas were taken and examined directly by scraping technique for endogenous stages. The distribution of C. baileyi in different tissues in the case of intratracheal inoculation; trachea 23 [92%] chicks infected, bursa of Fabricius 21 [84%] chicks, Cloaca 5 [16%] chicks, Colon 1 [4%] chick and the caeci showing no infection. Daily examination of the intratracheal droppings inoculation was done at the 5[th] day and lasted for 18-20 days, the patent period