Julian Kathleen G, Eidson Millicent, Kipp Aaron M, Weiss Erin, Petersen Lyle R, Miller James R, Hinten Steven R, Marfin Anthony A
Centers for Disease Control and Prevention, Fort Collins, Colorado 80522, USA.
Vector Borne Zoonotic Dis. 2002 Fall;2(3):145-55. doi: 10.1089/15303660260613710.
The 1999 New York epidemic of human West Nile virus (WN) encephalitis and meningitis was preceded by a crow die-off also caused by WN infection. As one component of the subsequently developed national surveillance system, crow mortality data were collected to detect WN activity before humans might become infected. However, predicting areas at risk for human WN disease likely requires assessment of multiple factors, including the intensity and timing of crow epizootics. To identify early season measures of WN activity in crows associated with subsequent WN disease in humans, county-level crow mortality data from seven northeastern states were analyzed. A predictive model was developed based on analysis of 2000 surveillance data and then assessed for 2001. To characterize the intensity of early season WN activity in crows, 15 variables were constructed from surveillance data of 52 counties that tested at least four crows during the early season (defined as June 17-July 28, 2000). County values for each variable were dichotomized at the 75th percentile into "high" and "low" activity. Multivariate analysis indicated that "high" early season activity of two variables-density of reported dead crow sightings (reported dead crows/area) and [(WN-infected crows/tested crows) x (human population)]--were associated with report of at least one human WN disease case (for each variable: adjusted odds ratio, 6.9; 95% confidence interval, 1.2-40.6). An assessment of this model using 2001 surveillance data from 61 counties yielded similar findings. With emphasis on early season WN activity, crow surveillance may allow timely targeting of interventions to protect the public health.
1999年纽约爆发的人类西尼罗河病毒（WN）脑炎和脑膜炎疫情之前，也曾出现过由WN感染导致的乌鸦死亡事件。作为随后建立的国家监测系统的一个组成部分，收集了乌鸦死亡率数据，以便在人类可能被感染之前检测WN的活动情况。然而，预测人类WN疾病的危险区域可能需要评估多个因素，包括乌鸦 epizootics 的强度和时间。为了确定与人类后续WN疾病相关的乌鸦早期WN活动指标，对来自东北部七个州的县级乌鸦死亡率数据进行了分析。基于对2000年监测数据的分析建立了一个预测模型，然后在2001年进行了评估。为了描述乌鸦早期WN活动的强度，从2000年早季（定义为2000年6月17日至7月28日）期间至少检测了四只乌鸦的52个县的监测数据中构建了15个变量。每个变量的县值在第75百分位数处分为“高”和“低”活动。多变量分析表明，两个变量的早季“高”活动——报告的死乌鸦目击密度（报告的死乌鸦/面积）和[（WN感染的乌鸦/检测的乌鸦）×（人口）]——与至少一例人类WN疾病病例的报告相关（对于每个变量：调整后的优势比为6.9；95%置信区间为1.2 - 40.6）。使用来自61个县的2001年监测数据对该模型进行评估得出了类似的结果。强调乌鸦的早期WN活动，乌鸦监测可能有助于及时确定干预目标以保护公众健康。
