PERSISTENT BOVINE PESTIVIRUS INFECTION LOCALIZED IN THE TESTES OF AN IMMUNO-COMPETENT, NON-VIREMIC BULL

A post-pubertal bull on an artificial insemination station was found t o be persistently shedding bovine viral diarrhoea virus (BVDV) in seme n over a period of eleven months, while demonstrating no viraemia. Cir culating antibodies to BVDV were consistently high, suggesting that th e immune system was challenged repeatedly. Post-mortem findings confir med that the virus was sequestered in the testes of the bull. It is hy pothesized that the BVDV in this immune-competent bull was protected f rom the bull's immune response by the blood-testes barrier. The barrie r becomes functional only at puberty when tight junctions form between adjacent Sertoli cells, suggesting that this bull became persistently infected with BVDV during puberty. (C) 1998 Elsevier Science B.V.