Detection of Classical Swine Fever virus in semen of infected boars

During the Classical Swine Fever (CSF) epidemic in 1997 in the EU member st ates Germany, Italy, Spain and The Netherlands, boars in an artificial inse mination (AI) centre were found to be infected with CSF virus. This raised a question of epidemiological importance which could not be answered immedi ately. Can CSF virus be shed by semen of infected boars and what conclusion s concerning the risk of spreading CSF infection by semen can be drawn. Exp erimental studies were conducted to answer this question. Four young boars were infected with a CSF field virus isolate from Germany, which had been characterised in a previous animal experiment. Semen was co llected at least every other day after infection. The semen was subjected t o the standard diagnostic procedure for the detection of CSF virus and to s emen quality assessment. The boars were euthanized at day 8, 12, 16 and 21 post infection, respectively. A post mortem examination was done and organ samples were taken from the CSF reference organs and genital organs for the detection of virus and antigen. The course of CSF infection of the boars w as mild but detectable during the second week of infection. CSF virus could be isolated from semen of two animals during the pyrexic phase and from th e epididymis but not from the testes. Since CSF virus shedding via semen co uld be proven, it was concluded that the disease may also be transmitted by artificial insemination. However analysis of semen in cell culture for the presence of CSF virus is not suitable as a routine method for CSF diagnosi s. (C) 2000 Elsevier Science B.V. All rights reserved.