Detection of bovine immunodeficiency virus DNA in the blood and semen of experimentally infected bulls

Five 18- to 24-month-old bulls were inoculated with either a cell suspensio n containing bovine immunodeficiency virus (BIV-FL112; 3 bulls) or a BIV-fr ee cell suspension (2 bulls). Blood and semen specimens were collected once a week for 14 weeks, and seroconversion was confirmed by indirect immunofl uorescent antibody (IFA) testing. The presence of BIV in blood and semen wa s determined by virus isolation and/or polymerase chain reaction (PCR) assa ys. Antibodies to BIV were detected in the 3 experimentally infected bulls as early as day post inoculation (DPI) 17, and levels peaked at DPI 37-58. BIV was isolated from the peripheral blood mononuclear cells (MNCs) of the infected bulls at DPI 9 (2 bulls) and DPI 23 (1 bull), and could be isolate d from one animal up to DPI 65. PCR analysis of MNC DNA, using BIV pol gene primers, detected virus in all three of the experimentally infected bulls from DPI 9 until the termination of the experiment at DPI 98. Efforts to is olate a significant number of non-spermatozoal cells (NSC) by gradient sepa ration from the semen of the experimentally infected bulls were unsuccessfu l. Two methods for the extraction of total NSC DNA from up to 2 mi of non-e xtended semen were employed; however, no BIV pol fragment was amplified fro m these DNA preparations. Additionally, 30 bulls from artificial inseminati on (AI) centers were evaluated for BIV infection by PCR. No amplification p roducts were obtained from MNC DNA from the Al submissions using primer set s for both the BTV pol and env genes. (C) 1999 Elsevier Science B.V. All ri ghts reserved.