PDF(Pubmed)
Abstract：
Since PCV4 was first described in 2019, the virus has been identified in several countries in Southeast Asia and Europe. Most studies have been limited to detecting PCV4 by PCR. Thus, PCV4 has an unclear association with clinical disease. This study utilized 512 porcine clinical lung, feces, spleen, serum, lymphoid tissue, and fetus samples submitted to the ISU-VDL from June-September 2023. PCV4 was detected in 8.6% of samples with an average Ct value of 33. While detection rates among sample types were variable, lymphoid tissue had the highest detection rate (18.7%). Two ORF2 sequences were obtained from lymphoid tissue samples and had 96.36-98.98% nucleotide identity with reference sequences. Direct detection of PCV4 by RNAscope revealed viral replication in B lymphocytes and macrophages in lymph node germinal centers and histiocytic and T lymphocyte infiltration in the lamina propria of the small intestine. PCV4 detection was most commonly observed in nursery to finishing aged pigs displaying respiratory and enteric disease. Coinfection with PCV2, PCV3, and other endemic pathogens was frequently observed, highlighting the complex interplay between different PCVs and their potential roles in disease pathogenesis. This study provides insights into the frequency of detection, tissue distribution, and genetic characteristics of PCV4 in the US.
摘要：
自2019年首次发现PCV4病毒以来，该病毒已在东南亚和欧洲的几个国家被发现。大多数研究仅限于通过PCR检测PCV4。因此，PCV4与临床疾病的相关性尚不清楚。本研究利用512家猪临床肺，粪便,脾,脾血清,淋巴组织,和从2023年6月至9月提交给ISU-VDL的胎儿样本。在8.6%的样品中检测到PCV4,平均Ct值为33。虽然样本类型之间的检出率是可变的，淋巴组织检出率最高(18.7%)。从淋巴组织样品中获得两个ORF2序列，与参考序列具有96.36-98.98％的核苷酸同一性。通过RNAscope直接检测PCV4显示淋巴结生发中心的B淋巴细胞和巨噬细胞中的病毒复制以及小肠固有层的组织细胞和T淋巴细胞浸润。PCV4检测最常见于苗圃至产龄猪，表现出呼吸道和肠道疾病。经常观察到与PCV2，PCV3和其他地方性病原体的共感染，强调不同PCV之间的复杂相互作用及其在疾病发病机理中的潜在作用。这项研究提供了对检测频率的见解，组织分布,和美国PCV4的遗传特征。
