Neoplastic response of guinea fowl to osteopetrosis virus strain MAV-2(0).

Newly hatched guinea fowl inoculated intravenously with avian osteopetrosis virus strain MAV-2(0) developed multiple bone tumours within 6 to 10 weeks. The extensive neoplastic bone formation was accomplished directly by proliferated periosteal osteoblasts as well as by endochondral ossification. Due to impaired ossification in the bone growths there occurred residual cartilage foci and bone-cartilagenous structures. Malignant zones with sarcomatous features were observed in severely affected bones. The infected guinea fowls also developed epithelial tumours of the pancreas and duodenal mucosa.