RESUMO
Papillomaviruses (PV) are double-stranded DNA viruses that can cause benignant and malignant tumors in amniotes. There are 13 types of bovine papillomavirus (BPV-1 to -13); they have been found in reproductive tissues and body fluids. Normally these viruses are detected in epithelial tissue. We looked for BPV in the blood of healthy cattle and cattle with papillomatosis, using PCR and RT-PCR. BPV types 1 and 2 were detected in 8/12 blood samples of asymptomatic bovines and in 8/9 samples from cattle with papillomatosis. Six of 8 asymptomatic samples positive for BPV also showed expression for BPV. Five of 6 samples were positive for E2 expression, while 3/6 samples were positive for E5 expression. Five of 8 symptomatic samples positive for BPV also showed BPV expression. Five of 5 were positive for E2 expression, while 1/5 was positive for E5 expression. Two of 6 blood samples of asymptomatic cattle and 1/5 symptomatic blood samples scored positive for both E2 and E5 expression. This is the first study showing expression of BPV genes in the blood of asymptomatic and papillomatosis-affected animals.