Christopher-Hennings J, Nelson E A, Hines R J, Nelson J K, Swenson S L, Zimmerman J J, Chase C L, Yaeger M J, Benfield D A
Department of Veterinary Science, South Dakota State University, Brookings 57007, USA.
J Vet Diagn Invest. 1995 Oct;7(4):456-64. doi: 10.1177/104063879500700406.
Four seronegative adult boars were intranasally inoculated with porcine reproductive and respiratory syndrome virus (PRRSV) isolate VR-2332. Serum and semen were collected 2-3 times weekly for over 100 days postinoculation (DPI). Serum samples were assayed for PRRSV by virus isolation (VI) and a polymerase chain reaction (PCR) and screened for antibodies to PRRSV using the indirect fluorescent antibody (IFA) and virus neutralization (VN) tests. Semen was assayed for PRRSV RNA by PCR. Virus and viral RNA was detected in the serum of all boars within 1 DPI by Vi and/or PCR. However, VI results indicated that viremia was transient and occurred from 1 to 9 DPI. Viral RNA was detected in serum from 1 to 31 DPI. In the acute stage of the infection, PRRSV RNA was detected in serum by PCR prior to the presence of viral RNA in semen. The PRRSV RNA was detected in semen as early as 3 DPI and persisted for 25 DPI in 2 of the boars and 56 and 92 DPI in the remaining 2 boars. Detection of PRRSV RNA in semen occurred 2-8 and 28-35 days prior to the detection of antibodies by IFA and VN, respectively. PRRSV was isolated from the bulbourethral gland of the boar that shed viral RNA in semen for 92 DPI. These results suggest that PRRSV RNA can be detected by PCR in boar serum and semen, and may persist for variable periods of time. Viremia and the serologic status of the boar are not adequate indicators of when PRRSV or PRRSV RNA is being shed in the semen. Preliminary findings also indicated that neither shipping stress nor reinoculation with homologous PRRSV resulted in viremia or viral RNA shedding in semen.
四只血清学阴性的成年公猪经鼻内接种猪繁殖与呼吸综合征病毒（PRRSV）毒株VR - 2332。在接种后超过100天（dpi）期间，每周采集2 - 3次血清和精液。通过病毒分离（VI）和聚合酶链反应（PCR）检测血清样本中的PRRSV，并使用间接荧光抗体（IFA）和病毒中和（VN）试验筛查针对PRRSV的抗体。通过PCR检测精液中的PRRSV RNA。在接种后1天内，通过VI和/或PCR在所有公猪的血清中检测到病毒和病毒RNA。然而，VI结果表明病毒血症是短暂的，发生在1至9 dpi。在1至31 dpi的血清中检测到病毒RNA。在感染的急性期，通过PCR在血清中检测到PRRSV RNA的时间早于精液中病毒RNA的出现。最早在3 dpi时在精液中检测到PRRSV RNA，在2头公猪中持续了25 dpi，在其余2头公猪中分别持续了56和92 dpi。精液中PRRSV RNA的检测分别比通过IFA和VN检测抗体早2 - 8天和28 - 35天。从精液中排出病毒RNA达92 dpi的公猪的尿道球腺中分离出PRRSV。这些结果表明，可通过PCR在公猪血清和精液中检测到PRRSV RNA，并且可能持续不同的时间段。公猪的病毒血症和血清学状态并不是PRRSV或PRRSV RNA何时在精液中排出的充分指标。初步研究结果还表明，运输应激或用同源PRRSV再次接种均未导致病毒血症或精液中病毒RNA的排出。
