Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, 1600 S. 16th Street, Ames, IA 50011, USA.
Vet Rec. 2012 Oct 27;171(17):425. doi: 10.1136/vr.100660. Epub 2012 Sep 5.
The objectives of this study were to further understand vertical transmission of porcine circovirus type 2 (PCV-2) and the effect of dam vaccination on PCV-2 viraemia in newborn piglets. Randomly selected sows from each of two breeding herds were designated as non-vaccinated or vaccinated groups. A commercial inactivated PCV-2 vaccine was administered at weaning and 18 days later to half of the sows on each farm. At parturition, colostrum was collected from 70 dams on each farm and postsuckle (Farm 1) or presuckle blood (Farm 2) was collected from five randomly selected piglets per litter. Colostrum samples had an anti-PCV-2 antibody prevalence of 98.5 per cent (135/137) with significantly (P = 0.0039) higher concentrations in vaccinated dams. Among piglets, 43.9 per cent (301/685) were seropositive for PCV-2 and 11.7 per cent (80/686) were PCV-2 DNA-positive. All the PCV-2 DNA-positive samples were further characterised and 28 were PCV-2a, 28 PCV-2b, and five mixed PCV-2a and PCV-2b infection. The prevalence of PCV-2 DNA in piglets was lower (0.7-22.8 per cent) compared with previous studies (44.8-90 per cent) indicating a change in PCV-2 ecology likely due to wide use of vaccination. Under the study conditions, dam vaccination reduced PCV-2 viraemia in the offspring with colostrum access.
本研究旨在进一步了解猪圆环病毒 2 型（PCV-2）的垂直传播情况，以及母猪免疫接种对新生仔猪 PCV-2 血症的影响。从两个繁殖场中随机选择母猪，分为未接种组和接种组。在每个农场，一半的母猪在断奶时和 18 天后接种商业化的 PCV-2 灭活疫苗。在分娩时，从每个农场的 70 头母猪中采集初乳，从每个窝的 5 头随机选择的仔猪中采集吮乳前（农场 1）或吮乳后（农场 2）血液。初乳样本的抗 PCV-2 抗体流行率为 98.5%（135/137），接种母猪的浓度明显更高（P = 0.0039）。在仔猪中，43.9%（301/685）为 PCV-2 血清阳性，11.7%（80/686）为 PCV-2 DNA 阳性。所有 PCV-2 DNA 阳性样本进一步进行特征分析，其中 28 个为 PCV-2a，28 个为 PCV-2b，5 个为 PCV-2a 和 PCV-2b 混合感染。与之前的研究（44.8-90%）相比，仔猪中 PCV-2 DNA 的流行率较低（0.7-22.8%），表明 PCV-2 生态学发生了变化，可能是由于广泛使用疫苗接种。在研究条件下，初乳可使仔猪接触到的母源抗体降低 PCV-2 血症。
