Pathogenicity difference to chicken using two Cryptosporidium baileyi isolates from chicken and duck.

Objective To study the pathogenicity difference of different Cryptosporidium baileyi isolates from chickens. Methods 3-day-old Roman chickens were inoculated with C. baileyi oocysts from chickens and ducks with a dosage of 1×106 per chicken. The oocyst shedding, clinical symptom, index of bursa of Fabricius and histopathology of infected groups were studied. Results No deaths were observed in the chicken-origin group, with the mobility rate of 25%. However, in the duck-origin group, the mobility and mortality rates were 35% and 5%, respectively. Conclusion C.baileyi from different origins can cause cryptosporidiosis in chicken. However, there were differences in the clinical signs, regulation of oocyst shedding, and the pathological changes of bursa of Fabricius.