Barker Christopher M, Brewster Carlyle C, Paulson Sally L
Department of Entomology, 216 Price Hall, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0319, USA.
J Am Mosq Control Assoc. 2003 Dec;19(4):382-91.
The number of cases of encephalitis caused by La Crosse virus recently has increased in southwestern Virginia counties. This article presents results of a study conducted from May to September 2000 in Wise County, VA, that examined the area-wide oviposition activity and habitat preferences of Ochlerotatus triseriatus and Aedes albopictus, potential vectors of La Crosse virus in the region. Data from 490 ovitrap collections made throughout the county showed that mean oviposition activity throughout the study was higher for Oc. triseriatus (20.4 eggs/trap-day) than for Ae. albopictus (3.7 eggs/trap-day). The 2 species also had distinct habitat preferences for oviposition, with Oc. triseriatus favoring forested habitats and Ae. albopictus favoring urban/residential habitats. A landcover map of 6 habitat types derived from Landsat satellite imagery of the county showed that 63% of the county was forested and 18% was urban/residential. A Bayesian decision-rule model that incorporated the ovitrap data and landcover map was moderately successful at predicting the occurrence of high oviposition activity and abundance of the 2 species. The predictions reflected seasonal and spatial fluctuations in oviposition activity, with accuracies between 55 and 79% for Oc. triseriatus and 70 and 94% for Ae. albopictus. Kappa (K), a measure of the predictive power of the model, varied from poor (K < 0.4) to good (0.4 < K < 0.75) for both species, and was highest during periods when actual egg abundance was high. This suggests that the predictions were most accurate during periods when the risk for La Crosse virus transmission is greatest. Limitations and suggestions for improving the model are discussed.
最近，弗吉尼亚州西南部各县由拉克罗斯病毒引起的脑炎病例数有所增加。本文介绍了2000年5月至9月在弗吉尼亚州怀斯县进行的一项研究结果，该研究调查了三带喙库蚊和白纹伊蚊的区域产卵活动及栖息地偏好，这两种蚊子是该地区拉克罗斯病毒的潜在传播媒介。全县490次诱蚊产卵器收集的数据显示，在整个研究期间，三带喙库蚊的平均产卵活动（20.4枚卵/诱蚊产卵器·日）高于白纹伊蚊（3.7枚卵/诱蚊产卵器·日）。这两个物种在产卵的栖息地偏好上也有所不同，三带喙库蚊更喜欢森林栖息地，而白纹伊蚊更喜欢城市/居民区栖息地。根据该县陆地卫星卫星图像得出的6种栖息地类型的土地覆盖图显示，该县63%为森林覆盖，18%为城市/居民区。一个纳入了诱蚊产卵器数据和土地覆盖图的贝叶斯决策规则模型在预测这两个物种的高产卵活动和丰富度方面取得了一定成功。预测结果反映了产卵活动的季节性和空间波动，三带喙库蚊的预测准确率在55%至79%之间，白纹伊蚊的预测准确率在70%至94%之间。卡帕系数（K）是衡量该模型预测能力的指标，两种蚊子的卡帕系数从较差（K<0.4）到良好（0.4<K<0.75）不等，在实际蚊卵数量较多的时期最高。这表明在拉克罗斯病毒传播风险最大的时期，预测最为准确。文中还讨论了该模型的局限性及改进建议。
