School of Environmental and Rural Science, University of New England, Armidale, New South Wales, Australia, 2351.
Faculty of Animal Sciences and Veterinary Medicine, Nong Lam University, Ho Chi Minh City, Vietnam.
Avian Dis. 2020 Dec 1;64(4):565-570. doi: 10.1637/0005-2086-64.4.565.
Dust collected from the poultry house has been increasingly used as a population-level sample to monitor the presence of pathogens or to evaluate the administration of live vaccines. However, there are no guidelines for the storage of this sample type. This study investigated the stability of infectious laryngotracheitis virus (ILTV), a DNA virus, and infectious bronchitis virus (IBV), an RNA virus, in poultry dust kept under temperature and moisture conditions that mimic on-farm and laboratory storage. Dust samples were collected from chicks spray vaccinated with a live IBV vaccine and inoculated with a field ILTV strain via eye drop. Samples were stored under different moisture conditions (dry = 2% moisture, moist = 22%-71% moisture) and temperatures (-20, 4, 25, and 37 C) for different durations (0, 7, and 14 days, and 1, 2, 3, and 4 mo) in a factorial arrangement, followed by quantitative PCR for detection of virus genome copies (GC). The length of storage, moisture level, and storage temperature affected the viral genome load for ILTV and IBV but did not affect the number of positive samples for each virus. All treatment combinations were ILTV positive for at least 4 mo. In dry dust samples, all storage temperatures or durations had quantifiable ILTV or IBV GC. Moisture addition had a detrimental effect on viral genome load, causing an overall reduction of 0.3 log 10 for ILTV GC (7.29 and 6.97 log 10, P = 0.0001), and 1.3 log 10 for IBV GC (5.95 and 4.66 log 10, P = 0.0001), which are unlikely to have biologic significance. In conclusion, dry dust can be stored at any temperature up to 37 C for at least 4 mo without loss in qPCR detection of ILTV or IBV GC. Collection or storage of moist dust should be avoided, or air drying prior to storage is recommended if only moist dust is available.
从家禽养殖场收集的灰尘越来越多地被用作群体水平的样本，以监测病原体的存在或评估活疫苗的使用效果。然而，目前尚无关于这种样本类型储存的指南。本研究调查了传染性喉气管炎病毒（ILTV）和传染性支气管炎病毒（IBV）在模拟农场和实验室储存条件下的稳定性，这两种病毒分别为 DNA 病毒和 RNA 病毒。从用活 IBV 疫苗喷雾接种的小鸡中采集灰尘样本，并通过滴眼接种田间分离的 ILTV 毒株。样本在不同的湿度条件（干燥 = 2%湿度，湿润 = 22%-71%湿度）和温度（-20、4、25 和 37°C）下储存不同的时间（0、7 和 14 天，以及 1、2、3 和 4 个月），然后进行定量 PCR 检测病毒基因组拷贝数（GC）。储存时间、湿度水平和储存温度均影响 ILTV 和 IBV 的病毒基因组负荷，但不影响每种病毒的阳性样本数量。所有处理组合在至少 4 个月内均为 ILTV 阳性。在干燥的灰尘样本中，所有储存温度或时间都可检测到可量化的 ILTV 或 IBV GC。添加水分对病毒基因组负荷有不利影响，导致 ILTV GC 总体减少 0.3 个对数 10（7.29 和 6.97 对数 10，P=0.0001），IBV GC 减少 1.3 个对数 10（5.95 和 4.66 对数 10，P=0.0001），这可能没有生物学意义。总之，干燥的灰尘可以在任何温度下储存长达 37°C，至少 4 个月，而不会导致 ILTV 或 IBV GC 的 qPCR 检测失败。如果只能获得潮湿的灰尘，则应避免收集或储存潮湿的灰尘，或者建议在储存前进行空气干燥。
