Cryptosporidium baileyi: effects of intra-abdominal and intravenous inoculation of oocysts on infectivity and site of development in broiler chickens

Developmental stages of Cryptosporidium baileyi were observed on the epithelium of the larynx, trachea, primary and secondary bronchi, air sacs, bursa of Fabricius, and cloaca of 12 chickens inoculated intra-abdominally with oocysts. All 12 birds inoculated intra-abdominally developed clinical signs of respiratory disease and had gross lesions of airsacculitis at necropsy. Developmental stages of C. baileyi and clinical signs of disease were not observed in 12 chickens inoculated intravenously with oocysts. The response of chickens to intra-abdominal inoculation of oocysts was similar to responses recorded following intratracheal inoculation of oocysts in previous studies. /// Se observaron varios estados de desarrollo del Cryptosporidium baileyi en el epitelio de la laringe, tráquea, bronquios primarios y secundarios, sacos aéreos, bolsa de Fabricio y cloaca de 12 pollos inoculados con oocistos por la vía abdominal. Todos los 12 pollos inoculados por esta vía desarrollaron signos clínicos de enfermedad respiratoria y a la necropsia tuvieron lesiones macroscópicas de aerosaculitis. No se observaron estados de desarrollo de C. baileyi ni signos clínicos en 12 pollos inoculados con oocistos por la vía intravenosa. La respuesta de los pollos a la inoculación intraabdominal con oocistos fué similar a la observada en estudios anteriores después de la inoculación de oocistos por la vía intratraqueal.