Papillomas and cancer in cattle

Area of Science:

• Veterinary Virology
• Oncology
• Immunosuppression

Background:

• Papillomaviruses cause epithelial cell hyperproliferation, forming papillomas, some of which can become malignant.
• Bovine papillomavirus type 4 (BPV-4) causes alimentary canal papillomas in cattle, potentially leading to carcinomas, especially with bracken fern consumption.
• Affected cattle often exhibit immunosuppression, increasing susceptibility to alimentary and urinary bladder cancers.

Purpose of the Study:

• To investigate the role of bovine papillomaviruses (BPV) in the development of alimentary and urinary bladder cancers in cattle.
• To determine if viral DNA is required for the maintenance of malignancy in experimentally induced cancers.
• To explore evidence of latent BPV infections and their association with cancer.

Main Methods:

• Experimental reproduction of papillomatosis and cancers in animals using bracken fern diet or azathioprine immunosuppression.
• Detection of viral DNA in naturally occurring and experimentally induced tumors using molecular methods.
• Observation of BPV-1 or BPV-2 skin wart development in immunosuppressed animals.

Main Results:

• No BPV DNA was detected in experimental upper alimentary canal or lower bowel cancers, indicating viral genome is not essential for maintaining malignancy.
• BPV-2 DNA was identified in natural and experimental bladder cancers, suggesting its involvement in latent infections and malignant transformation.
• BPV-1 or BPV-2 skin warts appeared in papillomatosis-free animals, providing further evidence of latent infections.

Conclusions:

• BPV can induce papillomas that may progress to cancer, with different BPV types associated with specific lesions.
• BPV-2 may play a role in latent infections and the development of bladder cancer in cattle.
• Findings have implications for understanding human papillomavirus-associated diseases and cancers.