Department of Population Health, Poultry Diagnostic and Research Center, College of Veterinary Medicine, University of Georgia, Athens, 30602, USA.
Avian Pathol. 2012;41(1):41-50. doi: 10.1080/03079457.2011.632402.
Currently, the aetiology of runting and stunting syndrome (RSS) in chickens is unknown. The impact of RSS on weight gain and microscopic lesions in immunological organs and the duodenum, was investigated in 1-day-old commercial broilers at 12 days following exposure to RSS-contaminated litter. Furthermore, the presence of the viral nucleic acids of three astroviruses and one parvovirus was analysed by in situ hybridization from days 1 through 5 post exposure. A 70% decrease in weight was observed in the RSS-exposed group at the end of the experiments when compared with the unexposed controls. Lesions in the bursa of Fabricius and thymus were present in both groups but were significantly higher at the end of the study in the RSS-exposed group. In contrast, no significant difference in Harderian gland lesions was observed between the groups. Histological lesions in the duodenum were already present 24 h after exposure in the RSS-exposed group only, peaked at day 4 and declined until the end of the study. Results of the in situ hybridization studies clearly indicate replication of three astroviruses (chicken astrovirus, avian nephritis virus [ANV]-1, ANV-2) in the duodenum but not in other organs evaluated. Chicken astrovirus nucleic acids were detected on days 1 and 2 post exposure, while ANV-1 and ANV-2 nucleic acids were observed on several days during the period investigated. Surprisingly, no viral nucleic acid specific for the chicken parvovirus was observed. The results indicate that astroviruses probably play an important role during RSS due to the concurrence of viral RNA detection and lesions in the duodenum.
目前，鸡矮小综合征（RSS）的病因尚不清楚。本研究在 1 日龄商品肉鸡接触 RSS 污染垫料后 12 天，检测 RSS 对增重的影响，以及对免疫器官和十二指肠的微观病变的影响。此外，还通过原位杂交技术，从接触后第 1 天到第 5 天，分析了三种星状病毒和一种细小病毒的病毒核酸。与未暴露对照组相比，暴露组在实验结束时体重下降了 70%。两组均出现法氏囊和胸腺病变，但暴露组在研究结束时病变更严重。相反，两组哈德腺病变无显著差异。暴露组仅在接触后 24 小时就出现十二指肠组织学病变，在第 4 天达到高峰，直至研究结束时才下降。原位杂交研究结果清楚地表明，三种星状病毒（鸡星状病毒、禽肾炎病毒[ANV]-1、ANV-2）在十二指肠中复制，但在其他评估器官中没有复制。在接触后第 1 天和第 2 天检测到鸡星状病毒核酸，而在研究期间的几天观察到 ANV-1 和 ANV-2 核酸。令人惊讶的是，未观察到鸡细小病毒的特异性病毒核酸。结果表明，由于在十二指肠中检测到病毒 RNA 和病变的同时发生，星状病毒可能在 RSS 中发挥重要作用。
