Department of Pathology and Wildlife Diseases, National Veterinary Institute (SVA), Uppsala, Sweden.
Section of Virology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
Avian Pathol. 2022 Jun;51(3):257-266. doi: 10.1080/03079457.2022.2048631. Epub 2022 Apr 11.
The present paper describes the investigation of the first outbreaks of adenoviral gizzard erosions (AGE) in Sweden, in five broiler flocks. The investigation included whole viral genome sequencing and investigation of genomic organization and sequence relationships with other adenoviruses. All five flocks had a history of decreased growth and uneven size of birds since 9-10 days of age. Macroscopically, lesions consistent with AGE (detached koilin layers, discolouration, bleeding, erosions) were identified in gizzards in all five flocks. In four flocks histology was performed, and degeneration and inflammation of the koilin layer and gizzard mucosa were identified in all four. In one flock, intranuclear inclusion bodies typical for fowl adenovirus (FAdV) were detected in trapped epithelial cells in the koilin layer. In four flocks hybridization was performed, and cells positive for FAdV serotype 1 (FAdV-1) were demonstrated in the koilin layer and gizzard mucosa. FAdV species A (FAdV-A) was detected in gizzard, liver, caecal tonsils and bursa of Fabricius by polymerase chain reaction (PCR) and sequencing. Ten out of ten examined parent flocks of the affected chickens were seropositive for FAdV, indicating former or on-going infection. However, FAdV was not detected in embryos from seropositive parent flocks and thus vertical transmission was not demonstrated. The entire nucleotide sequence of one sample was determined and found to be 43,856 base pairs (bp) in length. The genome sequence and organization were found to be similar to that of the reference apathogenic avian adenovirus "chicken embryo lethal orphan" (CELO). RESEARCH HIGHLIGHTSAGE in Swedish broilers: necropsy, histopathology, ISH, PCR, whole-genome sequencing.Whole FAdV-genome analysed: 43,856 bp, found to be most similar to CELO (U46933.1).Multiple point mutations, site insertions and deletions identified compared to CELO.Paper adds knowledge about European disease situation and pathogenic FAdV-strains.
本研究描述了在瑞典五批肉鸡群中首次爆发腺病毒肌胃炎（AGE）的情况。该研究包括全病毒基因组测序以及对基因组结构和与其他腺病毒的序列关系进行调查。所有五批肉鸡在 9-10 日龄后均出现生长缓慢和鸡群大小不均匀的历史。所有五批鸡的肌胃均出现了与 AGE（脱落的角质层、变色、出血、侵蚀）一致的病变。在四批鸡中进行了组织学检查，在所有四批鸡中均发现角质层和肌胃黏膜的退化和炎症。在其中一批鸡中，在角质层的被捕获上皮细胞中检测到典型的禽腺病毒（FAdV）的核内包涵体。在四批鸡中进行了杂交，在角质层和肌胃黏膜中检测到 FAdV-1 型（FAdV-1）阳性细胞。聚合酶链反应（PCR）和测序检测到 FAdV 种 A（FAdV-A）在肌胃、肝脏、盲肠扁桃体和法氏囊。受感染鸡的十批亲代鸡群中有十批对 FAdV 呈血清阳性，表明存在或正在发生感染。然而，在血清阳性的亲代鸡群的胚胎中未检测到 FAdV，因此未证明垂直传播。对一个样本的整个核苷酸序列进行了测定，发现其长度为 43856 个碱基对（bp）。基因组序列和组织与参考的无致病性禽腺病毒“鸡胚致死孤儿”（CELO）相似。研究亮点：瑞典肉鸡的 AGE：剖检、组织病理学、ISH、PCR、全基因组测序。全 FAdV 基因组分析：43856 bp，与 CELO（U46933.1）最相似。与 CELO 相比，鉴定出多个点突变、位点插入和缺失。本文增加了关于欧洲疾病情况和致病性 FAdV 株的知识。
