Preskenis Lauren A, Ladman Brian S, Gelb Jack
A Department of Animal and Food Sciences, Avian Biosciences Center, University of Delaware, Newark, DE 19716.
Avian Dis. 2017 Mar;61(1):83-89. doi: 10.1637/11461-062716-Reg.
Wild waterfowl and shorebirds in the Delaware-Maryland-Virginia (Delmarva) Peninsula region within the Atlantic Flyway were sampled as part of the Early Detection of Highly Pathogenic H5N1 Avian Influenza (AI) in Wild Migratory Birds program. The U.S. Department of Agriculture (USDA) and state wildlife agencies submitted 7858 samples for AI virus (AIV) testing by real-time reverse transcription PCR (rRT-PCR) to the University of Delaware Poultry Health System from April 2007 to March 2011. Virus isolation attempts were performed on samples with matrix gene cycle threshold (Ct) values ≤33.9. Using rRT-PCR, AIV was detected in 14% (1091/7857) of the samples. In species with sample sizes >100, American black duck ( Anas rubripes ; 28%), ruddy turnstone ( Arenaria interpres ; 27%), American green-winged teal ( Anas crecca ; 21%), semipalmated sandpiper ( Calidris pusilla ; 27%), greater snow goose ( Chen caerulescens atlanticus; 12%), mallard ( Anas platyrhynchos ; 10%), and northern pintail ( Anas acuta ; 14%) showed the highest rates of AIV detection. Forty-two AIVs were recovered from eight species: American black duck, mallard, ruddy turnstone, American green-winged teal, greater snow goose, Canada goose ( Branta canadensis ), ring-necked duck ( Aythya collaris ), and mallard × American black duck ( Anas platyrhynchos × Anas rubripes ). Recovered H5 (n = 2) and H7 (n = 2) viruses were found to be low pathogenicity by the USDA National Veterinary Services Laboratory. Additional AIVs represented a diversity of subtype combinations: H1-H4, H6, and H10 and H11 and N subtypes N1-N9 and N6-N9. The rate of AIV recovery from swabbings was inversely related to Ct value, ranging from 50% for Ct values of 16.0-18.9 to 5.1% for Ct values of 31-33.9.
作为野生候鸟高致病性H5N1禽流感早期检测计划的一部分，对大西洋迁徙路线上特拉华-马里兰-弗吉尼亚（德尔马瓦）半岛地区的野生水禽和滨鸟进行了采样。2007年4月至2011年3月，美国农业部（USDA）和各州野生动物机构向特拉华大学家禽健康系统提交了7858份样本，用于通过实时逆转录PCR（rRT-PCR）检测禽流感病毒（AIV）。对基质基因循环阈值（Ct）值≤33.9的样本进行病毒分离尝试。使用rRT-PCR，在14%（1091/7857）的样本中检测到AIV。在样本量>100的物种中，美洲黑鸭（Anas rubripes；28%）、赤颈鸻（Arenaria interpres；27%）、美洲绿翅鸭（Anas crecca；21%）、半蹼鹬（Calidris pusilla；27%）、大雪雁（Chen caerulescens atlanticus；12%）、绿头鸭（Anas platyrhynchos；10%）和针尾鸭（Anas acuta；14%）的AIV检测率最高。从8个物种中分离出42株AIV：美洲黑鸭、绿头鸭、赤颈鸻、美洲绿翅鸭、大雪雁、加拿大雁（Branta canadensis）、环颈鸭（Aythya collaris）和绿头鸭×美洲黑鸭（Anas platyrhynchos×Anas rubripes）。美国农业部国家兽医服务实验室发现，分离出的H5（n = 2）和H7（n = 2）病毒为低致病性。其他AIV代表了多种亚型组合：H1-H4、H6以及H10和H11，N亚型为N1-N9和N6-N9。从拭子中分离AIV的比率与Ct值呈负相关，Ct值为16.0-18.9时为50%，Ct值为31-33.9时为5.1%。
