Kuiken T, Leighton F A, Wobeser G, Danesik K L, Riva J, Heckert R A
Canadian Cooperative Wildlife Health Centre, Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada.
J Wildl Dis. 1998 Jul;34(3):457-71. doi: 10.7589/0090-3558-34.3.457.
A Newcastle disease epidemic in double-crested cormorants (Phalacrocorax auritus) occurred in July and August 1995, during a 1994-96 study of a breeding colony of this species on Doré Lake (Saskatchewan, Canada). Clinical signs and mortality were observed from a tunnel-and-blind system, and moribund and freshly dead birds were examined virologically. Yolks from cormorant eggs and sera from cormorants and other birds were tested for hemagglutination inhibiting antibodies to Newcastle disease virus (NDV). Evidence of Newcastle disease was limited to juvenile double-crested cormorants, despite close contact with other birds, including American white pelicans (Pelecanus erythrorhynchos) and gulls (Larus spp.). Clinical signs included limb, head or neck paralysis, head or body tremors, ataxia, and blindness; pathogenic NDV was isolated from affected birds. The mortality rate of juvenile cormorants was 32 to 64%, which was high relative to overall first-year mortality in years without epidemics. Thirty-seven of 63 (59%) cormorant sera collected during the epidemic tested positive for antibodies to NDV. Antibody status of cormorant egg yolks depended on stage of incubation, likely due to changes in the amount of water in the yolks. The departure of juvenile cormorants from their nests at 4 wk of age, resulting in an increased contact rate among individuals, may have been important in triggering the epidemic.
1995年7月和8月，在对加拿大萨斯喀彻温省多雷湖一个双冠鸬鹚繁殖群体进行的1994 - 1996年研究期间，该群体发生了新城疫疫情。通过一个隧道和盲端系统观察到了临床症状和死亡率，并对濒死和刚死亡的鸟类进行了病毒学检查。检测了鸬鹚卵黄以及鸬鹚和其他鸟类的血清中针对新城疫病毒（NDV）的血凝抑制抗体。尽管与包括美洲白鹈鹕（Pelecanus erythrorhynchos）和海鸥（Larus spp.）在内的其他鸟类密切接触，但新城疫的证据仅限于幼年双冠鸬鹚。临床症状包括肢体、头部或颈部麻痹、头部或身体震颤、共济失调和失明；从患病鸟类中分离出了致病性新城疫病毒。幼年鸬鹚的死亡率为32%至64%，相对于非疫情年份的总体第一年死亡率而言较高。在疫情期间采集的63份鸬鹚血清中有37份（59%）检测出新城疫病毒抗体呈阳性。鸬鹚卵黄的抗体状态取决于孵化阶段，这可能是由于卵黄中水量的变化所致。幼年鸬鹚在4周龄时离开巢穴，导致个体间接触率增加，这可能对引发疫情起到了重要作用。
