Eddicks Matthias, Szikora Florian, Walhöfer Nils, Sauter Louis Carola, Reese Sven, Banholzer Elisabeth, Reiner Gerald, Sutter Gerd, Ritzmann Mathias, Fux Robert
Dr. Matthias Eddicks, Klinik für Schweine, Ludwig-Maximilians-Universität München, Sonnenstraße 16, 85764 Oberschleißheim, E-Mail:
Tierarztl Prax Ausg G Grosstiere Nutztiere. 2017 Apr 19;45(2):90-97. doi: 10.15653/TPG-160547. Epub 2017 Mar 22.
Since 2004/2005 a worldwide shift of the detection rate of porcine circovirus (PCV) has been observed from PCV2a towards PCV2b. Currently commercially available vaccines are based on genotype PCV2a. The study was conducted as a pilot study to evaluate the occurrence of PCV2a and PCV2b in farms with different vaccination strategies against PCV2.
For this purpose a total of 405 piglets originating from nine farms (three farms with sow vaccination [SI], piglet vaccination [FI] and no vaccination [NI] against PCV2, respectively) were enrolled and followed from day 3 of life until slaughter. Serum of the piglets was examined for PCV2-DNA by quantitative PCR, genotype differentiating duplex PCR, and after sequencing of the total genome, PCV2 isolates were phylogenetically assigned. The evaluation included the data from 383 animals.
In eight farms PCV2 could be detected (1x PCV2a; 6x PCV2b; 1x PCV2a and PCV2b). PCV2b was found in SI-, NI- and FI-farms, whereas PCV2a was only detected in SI- and NI-farms. A proportion of 55.4% was PCV2-positive at least once during the entire study period (FI: 7.8%, SI: 65.4%, NI: 93.7%). Of these samples 4.7% were PCV2a-, 92.2% PCV2b- and 2.4% PCV2a- and PCV2b-positive. The mean content of PCV2-DNA in the serum of PCV2b positive animals was significantly higher than from PCV2a positive animals. PCV2 isolates were identified as PCV2b-1A (5/9 farms), PCV2b-1B (1/9 farms) und PCV2a-2D (2/9 farms).
The increased detection rate of PCV2b in comparison to PCV2a could be confirmed. The present study gives hint that the vaccination of piglets using PCV2a-based vaccines may lead to a further shift of the detection rate from PCV2a to PCV2b. To assess the clinical relevance of this observation, extensive comparative studies should be taken into account, which also evaluate the efficacy of PCV2a-based vaccines in PCV2a- and PCV2b-positive farms.
自2004/2005年以来，已观察到全球范围内猪圆环病毒（PCV）的检出率从PCV2a向PCV2b转变。目前市售疫苗基于PCV2a基因型。本研究作为一项试点研究，旨在评估不同PCV2疫苗接种策略的猪场中PCV2a和PCV2b的发生情况。
为此，共纳入了来自9个猪场的405头仔猪（分别有3个猪场对母猪进行了PCV2疫苗接种[SI]、对仔猪进行了PCV2疫苗接种[FI]以及未进行PCV2疫苗接种[NI]），并从出生后第3天开始跟踪直至屠宰。通过定量PCR、基因型区分双链PCR检测仔猪血清中的PCV2-DNA，并在对全基因组进行测序后将PCV2分离株进行系统发育分类。评估纳入了383只动物的数据。
在8个猪场中检测到了PCV2（1个猪场为PCV2a；6个猪场为PCV2b；1个猪场为PCV2a和PCV2b）。在SI、NI和FI猪场中均发现了PCV2b，而PCV2a仅在SI和NI猪场中检测到。在整个研究期间，有55.4%的仔猪至少有一次PCV2呈阳性（FI：7.8%，SI：65.4%，NI：93.7%）。在这些样本中，4.
