US Geological Survey, Northern Prairie Wildlife Research Center, Jamestown, ND 58401, USA.
Am J Trop Med Hyg. 2013 Jun;88(6):1152-8. doi: 10.4269/ajtmh.12-0408. Epub 2013 Mar 25.
West Nile virus (WNV) causes significant mortality of American White Pelican chicks at northern plains colonies. We tested oropharyngeal/cloacal swabs from moribund chicks for shed WNV. Such shedding could enable chick-to-chick transmission and help explain why WNV spreads rapidly in colonies. WNV was detected on swabs from 11% of chicks in 2006 and 52% of chicks in 2007; however, viral titers were low. Before onset of WNV mortality, we tested blood from < 3-week-old chicks for antibodies to WNV; 5% of chicks were seropositive, suggesting passive transfer of maternal antibodies. Among near-fledged chicks, 41% tested positive for anti-WNV antibodies, indicating that they survived infection. Among years and colonies, cumulative incidence of WNV in chicks varied from 28% to 81%, whereas the proportion of chicks surviving WNV (i.e., seropositive) was 64-75%. Our data revealed that WNV kills chicks that likely would fledge in the absence of WNV, that infection of chicks is pervasive, and that significant numbers of chicks survive infection.
西尼罗河病毒（WNV）导致北平原聚居区的美洲白鹈鹕雏鸟大量死亡。我们检测了濒死雏鸟的咽/泄殖腔拭子，以检测其排出的 WNV。这种排出可能会导致雏鸟之间的传播，并有助于解释为什么 WNV 在聚居区迅速传播。2006 年，11%的雏鸟拭子中检测到 WNV，而 2007 年则有 52%的雏鸟拭子中检测到 WNV；然而，病毒滴度较低。在 WNV 死亡率出现之前，我们检测了<3 周龄雏鸟血液中的 WNV 抗体；5%的雏鸟呈血清阳性，表明了母源抗体的被动转移。在即将孵化的雏鸟中，41%的雏鸟对抗 WNV 抗体呈阳性，表明它们已感染但幸存下来。在不同年份和聚居区中，雏鸟的 WNV 累积发病率从 28%到 81%不等，而幸存 WNV（即血清阳性）的雏鸟比例为 64-75%。我们的数据表明，WNV 杀死了那些在没有 WNV 的情况下可能会孵化的雏鸟，感染雏鸟的情况普遍存在，并且大量雏鸟幸存下来。
