Center for Vectorborne Diseases, Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California 95616, USA.
Am J Trop Med Hyg. 2010 Oct;83(4):808-15. doi: 10.4269/ajtmh.2010.10-0200.
Each spring large numbers of neotropical migrants traversing the Pacific flyway pass through the Coachella Valley enroute to northern destinations, providing an opportunity to test the hypothesis that mosquito-borne encephalitis viruses are introduced annually into California by migratory birds. A total of 5,632 sera were collected from 43 species of migrants during spring (April-June), of which 34 (0.61%) comprised of 14 species tested positive by enzyme immunoassay; only 10 were confirmed by plaque reduction neutralization tests (PRNT). In addition, of 1,109 migrants comprised of 76 species that were reported dead by the public and necropsied, 126 (11%) were positive for West Nile virus (WNV) RNA; however, only three (0.7%) of 428 birds tested during the spring were positive. Limited experimental infection studies with WNV showed that Orange-crowned Warblers were highly susceptible and frequently died, whereas most Yellow Warblers survived. Our results indicated that birds entering California rarely exhibited a history of infection and that most birds probably became infected after entering California.
每年春天，大量穿越太平洋迁徙通道的新热带候鸟在飞往北方目的地的途中经过科切拉谷，这为测试以下假设提供了机会：即蚊子传播的脑炎病毒是否每年由候鸟引入加利福尼亚。在春季（4 月至 6 月），从 43 种候鸟中采集了 5632 份血清，其中 34 份（0.61%）由 14 种通过酶联免疫吸附试验检测呈阳性；仅 10 份通过蚀斑减少中和试验（PRNT）得到确认。此外，在 1109 只由 76 种报告死亡并进行剖检的候鸟中，126 只（11%）WNV RNA 检测呈阳性；然而，在春季检测的 428 只鸟类中，仅有 3 只呈阳性。WNV 的有限实验感染研究表明，橙顶莺高度易感且经常死亡，而大多数黄莺存活下来。我们的结果表明，进入加利福尼亚的鸟类很少有感染史，而且大多数鸟类可能是在进入加利福尼亚后才感染的。
