University of Nottingham, School of Veterinary Medicine and Science, Sutton Bonington LE12 5RD, United Kingdom.
Vet Microbiol. 2011 May 5;149(3-4):452-5. doi: 10.1016/j.vetmic.2010.11.019. Epub 2010 Nov 21.
We investigated the on-farm potential of common farm invertebrates to transmit porcine circovirus genotype 2 (PCV2) and other non-enveloped viruses. In 2007 (pre-PCV2 vaccination) and 2008 (post-PCV2 vaccination), invertebrate communities were trap-collected (8 trap-dates per year), counted and sorted into genus and species groups on 5 farm study sites within England. Total DNA was extracted from feces of representational cross-sections of pigs on each farm in each year and also from intact samples of Diptera flies (ca. 20 flies per trap) and dissected viscera of any cockroaches (ca. 5 per trap). Each DNA sample was tested for the presence of PCV2 DNA by separate PCRs for ORF1 and ORF2. Positive samples were sub-typed via DNA sequencing of PCR products. The pig-associated Diptera fly community was dominated by Musca domestica (house fly) in both years on all 5 farms; numerous Blatta orientalis cockroaches were only noted on 1 farm throughout. Specific PCV2b DNA elements were routinely detected (25-60% of samples) in weaner/nursery pig feces in 2007, but not in other age groups. Musca collected on 4 of the 5 farms in 2007 was also positive for PCV2b DNA elements. Comparison of ORF2 sequences indicated that ORF2 sequences indicating PCV2b genotype were identical in pigs and flies. Minor changes were noted in ORF1 sequences from different samples. Flies collected in the weaner/nursery area were most likely to be positive (22-50% of fly-trap samples). DNA extracted from all cockroaches (2007 and 2008) and all flies and pig feces in 2008 were also negative throughout. We suggest that Musca flies have the most likely on-farm potential to carry and transmit PCV2b due to their life cycle incorporating stages in close association with pigs and their habitat. Vaccination appeared to reduce environmental load of PCV2b.
我们研究了常见农场无脊椎动物在传播猪圆环病毒 2 型（PCV2）和其他非包膜病毒方面的田间潜力。2007 年（PCV2 疫苗接种前）和 2008 年（PCV2 疫苗接种后），在英格兰的 5 个农场研究点，用陷阱收集无脊椎动物群落（每年 8 个陷阱日期）、计数并按属和种分类。从每个农场每年的代表性猪粪便中提取总 DNA，还从每个陷阱中的约 20 只苍蝇的完整样本和每个陷阱中的约 5 只蟑螂的解剖内脏中提取总 DNA。用针对 ORF1 和 ORF2 的单独 PCR 检测每个 DNA 样本中是否存在 PCV2 DNA。通过对 PCR 产物的 DNA 测序对阳性样本进行亚分型。在这两年中，所有 5 个农场的猪相关的家蝇（家蝇）都占优势；在整个农场中，只注意到许多东方蟑螂。2007 年，断奶/保育猪粪便中常规检测到特定的 PCV2b DNA 元件（25-60%的样本），但在其他年龄组中未检测到。2007 年在 5 个农场中的 4 个农场收集的家蝇也检测到 PCV2b DNA 元件。对 ORF2 序列的比较表明，猪和蝇中的 ORF2 序列指示 PCV2b 基因型相同。从不同样本中注意到 ORF1 序列的微小变化。在育肥/保育区收集的苍蝇最有可能呈阳性（22-50%的蝇陷阱样本）。从 2007 年和 2008 年的所有蟑螂和 2008 年的所有苍蝇和猪粪便中提取的 DNA 也始终为阴性。我们认为，由于家蝇的生命周期包含与猪密切相关的阶段及其栖息地，因此它们在农场中最有可能携带和传播 PCV2b。疫苗接种似乎减少了 PCV2b 的环境负荷。
