■由CIA病毒(CIAV)引起的鸡传染性贫血(CIA)被认为是影响鸡的最重要的免疫抑制疾病之一,最近对全世界的家禽业造成了巨大的经济负担。
■本研究旨在确定湄公河三角洲(MD)中是否存在CIAV,越南,并确定目前在该地区流通的CIAVs的基因型。
■器官样本(脾脏,肝脏,和胸腺)从47个家禽养殖场收集了144只怀疑使用CIA的鸡。共收集了47个样本,每个农场都有2-4只鸡,测试了CIAV的存在。
■使用靶向病毒VP1基因的聚合酶链反应,47个合并器官样品中的20个(每个农场2-4只鸡)对CIAV呈阳性。对八个代表性CIAV的VP1扩增子进行测序和遗传表征。基于部分VP1基因序列的系统发育分析表明,在MD中检测到的CIAVs分为不同的II基因型,IIIa,和IIIc以及先前在越南北部和其他亚洲国家发现的CIAV。系统发育分析还证实,检测到的CIAVs在遗传上与疫苗株不同。此外,推导的VP1氨基酸鉴定了VP1蛋白中的几个关键氨基酸取代,这些取代可能与CIAV的毒力有关。
■这是检测和确定MD中循环CIAV的遗传特征的第一份报告。因此,这项研究提供了对CIAVs演变的重要理解,并强调了在MD和越南对CIAVs实施迅速控制措施的重要性。
Chicken infectious anemia (CIA) caused by the CIA virus (CIAV) is considered one of the most important immunosuppressive diseases affecting chickens and recently poses a great economic burden to the poultry industry worldwide.
This study aims to identify the presence of CIAV in the Mekong Delta (MD), Vietnam, and to determine genotypes of CIAVs that are currently circulating in this area.
Organ samples (spleen, liver, and thymus) of 144 chickens suspected with CIA from 47 poultry farms were collected. A total of 47 pooled samples, each containing 2-4 chickens from each farm, were tested for the presence of CIAV.
Twenty out of 47 pooled organ samples (pool of 2-4 chickens per farm) were positive for CIAV using polymerase chain reaction targeting the viral VP1 gene. The VP1 amplicons of eight representative CIAVs were subjected to sequencing and genetic characterization. Phylogenetic analysis based on partial VP1 gene sequence revealed that the CIAVs detected in the MD grouped into different genotypes of II, IIIa, and IIIc together with CIAVs previously detected in the northern Vietnam and other Asian countries. The phylogenetic analysis also confirmed that detected CIAVs genetically differed from vaccine strains. In addition, deduced amino acids of the VP1 identified several critical amino acid substitutions in the VP1 protein that are likely associated with the virulence of CIAV.
This is the first report to detect and determine the genetic characterization of the circulating CIAVs in the MD. Therefore, this study provides an important understanding of the evolution of CIAVs and highlights the importance of implementing prompt control measures against CIAVs in the MD and Vietnam.