Ward Michael P, Raim Arlo, Yaremych-Hamer Sarah, Lampman Richard, Novak Robert J
Illinois Natural History Survey Champaign, 61820, USA.
Am J Trop Med Hyg. 2006 Aug;75(2):350-5.
The potential role of many urban passerine birds in the transmission of West Nile virus (WNV) is well-documented by studies on host competency, seroprevalence in wild birds, and identification of vector blood meal source. In contrast, the impact of bird behavior on transmission dynamics is largely unexplored. Bird roosting (perching) behavior may be a critical component regulating WNV transmission because of the crepuscular/nocturnal feeding behavior of Culex mosquitoes, the primary vectors of WNV. We used radio telemetry to determine the roosting behavior of American crows (Corvus brachyrhynchos) and northern cardinals (Cardinalus cardinalus). On average, healthy crows moved slightly shorter distances between roosts than viremic crows, 1,038.3 meters versus 1,255.5 meters, while cardinals only moved 54.7 meters. Given the average movements of crows and cardinals between roosts, crows, which are viremic for five days, could spread the virus throughout a mean +/- SE area of 20.84 +/- 0.79 km(2), while viremic cardinals would, on average, only spread the virus over a mean +/- SE area of 0.03 +/- 0.01 km(2). Because the crow population in Illinois is decreasing at a rate of 11.5% per year and up to 35.6% per year in certain locations, crows are becoming scarce in some areas, thus reducing their role as wild bird sentinels. We suggest that if crows are important in dispersing WNV, large decreases in their abundance will shift transmission cycles to a more focal nature because of the differences in roosting behavior of crows compared with other urban birds, such as cardinals.
关于许多城市食虫鸟类在西尼罗河病毒（WNV）传播中的潜在作用，已有多项研究通过宿主易感性、野生鸟类血清阳性率以及确定媒介昆虫血餐来源等方面进行了充分记录。相比之下，鸟类行为对传播动态的影响在很大程度上尚未得到充分探索。鸟类栖息（栖息）行为可能是调节WNV传播的关键因素，这是因为WNV的主要传播媒介库蚊具有黄昏/夜间觅食行为。我们使用无线电遥测技术来确定美洲乌鸦（短嘴鸦）和北美红雀（主红雀）的栖息行为。平均而言，健康乌鸦在栖息地之间移动的距离略短于感染病毒的乌鸦，分别为1038.3米和1255.5米，而北美红雀仅移动了54.7米。考虑到乌鸦和北美红雀在栖息地之间的平均移动距离，感染病毒五天的乌鸦能够将病毒传播到平均±标准误为20.84±0.79平方公里的区域，而感染病毒的北美红雀平均仅能将病毒传播到平均±标准误为0.03±0.01平方公里的区域。由于伊利诺伊州的乌鸦数量正以每年11.5%的速度减少，在某些地区每年减少高达35.6%，乌鸦在一些地区正变得稀少，从而降低了它们作为野生鸟类哨兵的作用。我们认为，如果乌鸦在传播WNV方面很重要，其数量的大幅减少将使传播周期转向更具局部性的性质，因为与其他城市鸟类（如北美红雀）相比，乌鸦的栖息行为存在差异。
