Detection and duration of porcine reproductive and respiratory syndrome virus in semen, serum, peripheral blood mononuclear cells, and tissues from Yorkshire, Hampshire, and Landrace boars
Detection and duration of porcine reproductive and respiratory syndrome virus in semen, serum, peripheral blood mononuclear cells, and tissues from Yorkshire, Hampshire, and Landrace boars
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DOI：
10.1177/104063870101300207
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发表时间：
2001-03-01
影响因子：
1.5
通讯作者：
Nelson, EA
中科院分区：
文献类型：
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作者：
Christopher-Hennings, J;Holler, LD;Nelson, EA
由于猪繁殖与呼吸综合征病毒（PRRSV）可以通过公猪精液传播，因此识别持续感染的公猪非常重要。然而，即使对于给予相同的PRRSV毒株和剂量的公猪，也观察到精液中病毒脱落持续时间的变异性，这表明宿主因素参与了PRRSV的持久性。为了确定是否存在宿主遗传因素，特别是与PRRSV持续存在相关的窝仔和品种差异，本研究使用了来自3个纯种猪品种的3窝仔。还确定了是否可以在血清、精液或外周血单核细胞（PBMC）中检测到较长时间的PRRSV，以及在这些生前检查后是否仍可以在组织中检测到PRRSV。标本至少2-3周为PRRSV阴性。获得3头汉普郡、3头约克郡和2头长白猪PRRSV-未感染公猪，并鼻内接种野生型PRRSV分离株（SD-23983）。每个品种内的所有野猪均来自同一窝，且窝仔均在9日龄内。每周两次从每头公猪收集血清和PBMC，并通过病毒分离和聚合酶链反应（PCR）分析PRRSV的存在。还使用血清获得病毒中和滴度和酶联免疫吸附测定S/P值。每周两次从8头公猪中的7头收集精液，并通过PCR进行分析。在所有标本均为PRRSV阴性至少2-3周后，对每头公猪实施安乐死，并收集21个组织加上唾液、血清、粪便和尿液。通过病毒分离评价所有尸检标本。然后通过PCR评价通过病毒分离为PRRSV阴性的标本。对于长白猪、约克郡公猪和汉普郡公猪，精液中PRRSV散毒持续时间的平均天数（SD）分别为51 +/- 26.9天、7.5 +/- 4.9天和28.3 +/- 17.5天。由于样本量小和SD大，认为不同品种之间精液中PRRSV散毒持续时间的差异不显著。然而，这一趋势表明，约克郡公猪比长白猪公猪对精液中的PRRSV脱落更有抵抗力，需要使用更大数量的公猪进行进一步调查。7头公猪中有4头在精液中检出PRRSV的时间较血清或PBMC长。8头公猪中有6头在血清中检测到病毒血症，持续时间比PBMC长。在至少2-3周的PRRSV阴性血清、精液和PBMC后，通过病毒分离在8头公猪中的3头的扁桃体中仍然可以检测到PRRSV，这表明即使生前标本为PRRSV阴性，公猪的扁桃体中仍然携带有PRRSV。
Because transmission of porcine reproductive and respiratory syndrome virus (PRRSV) can occur through boar semen, it is important to identify persistently infected boars. However, even for boars given the same PRRSV strain and dose, variability in the duration of viral shedding in semen has been observed, suggesting that host factors are involved in PRRSV persistence. To determine whether there are host genetic factors, particularly litter and breed differences related to the persistence of PRRSV, 3 litters from 3 purebred swine breeds were used for this study. It was also determined whether PRRSV could be detected for a longer period of time in serum, semen, or peripheral blood mononuclear cells (PBMC) and if PRRSV could still be detected in tissues after these antemortem. specimens were PRRSV negative for a minimum of 2-3 weeks. Three Hampshire, 3 Yorkshire, and 2 Landrace PRRSV-naive boars were obtained and inoculated intranasally with a wildtype PRRSV isolate (SD-23983). All boars within each breed were from the same litter, and litters were within 9 days of age. Serum and PBMC were collected twice weekly from each boar and analyzed for the presence of PRRSV by virus isolation and the polymerase chain reaction (PCR). Serum was also used to obtain virus neutralization titers and enzyme-linked immunosorbent assay S/P values. Semen was collected twice weekly from 7 of 8 boars and analyzed by PCR. After all specimens were PRRSV negative for a minimum of 2-3 weeks, each boar was euthanized, and 21 tissues plus saliva, serum, feces, and urine were collected. All postmortem specimens were evaluated by virus isolation. Specimens that were PRRSV negative by virus isolation were then evaluated by PCR. The mean number of days ( SD) for the duration of PRRSV shedding in semen was 51 +/- 26.9 days, 7.5 +/- 4.9 days, and 28.3 +/- 17.5 days for Landrace, Yorkshire, and Hampshire boars, respectively. Because of small sample sizes and large SDs, the differences in duration of PRRSV shedding in semen between breeds were not considered significant. However, the trend suggested that Yorkshire boars were more resistant to PRRSV shedding in semen than were Landrace boars, requiring further investigation using a larger numbers of boars. PRRSV was detected for a longer period in semen than in serum or PBMC in 4 of 7 boars. Viremia could be detected for a longer period in serum than in PBMC in 6 of 8 boars. After a minimum of 2-3 weeks of PRRSV-negative serum, semen, and PBMC, PRRSV could still be detected in the tonsil of 3 of 8 boars by virus isolation, indicating that boars still harbor PRRSV within the tonsil even though antemortem specimens are PRRSV negative.