EXAMINATION OF VIRUS SHEDDING IN SEMEN FROM VACCINATED AND FROM PREVIOUSLY INFECTED BOARS AFTER EXPERIMENTAL CHALLENGE WITH PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS

Danish artificial insemination (AI) centres house several boars antibo dy positive to porcine reproductive and respiratory syndrome virus as well as PRRSV-naive boars which may become acutely infected, The risk of transmission of PRRSV by semen may therefore constitute a serious p roblem to the Danish pig industry. The use of a vaccination-program ma y be a way to avoid or reduce the problem, This study evaluates the us e of two vaccines: One live, attenuated vaccine and one inactivated va ccine, A pronounced reduction in viremia and shedding of virus in seme n was demonstrated by use of the live vaccine compared to the non-vacc inated control animals. In contrast, no changes in onset, level and du ration of viremia and shedding of virus in semen were observed using t he inactivated vaccine, Neither viremia nor seminal shedding of virus was detected in previously PRRSV-infected, PRRSV-antibody positive boa rs after challenge with a Danish field strain of PRRSV.