Wegbreit J, Reisen W K
Arbovirus Research Unit, Center for Vector-borne Disease Research, School of Veterinary Medicine, University of California, Davis 95616, USA.
J Am Mosq Control Assoc. 2000 Mar;16(1):22-7.
The summer abundance of Culex tarsalis in Kern County, California, during 1990-98 was related quantitatively to rainfall, snow depth and water content, and runoff of the Kern River. Total monthly rain that fell during winter, lagged by 4-6 months, explained only 13% of the variability in the number of host-seeking females collected per trap night per month during summer. In contrast, regression analysis showed that river runoff 1 month earlier explained 67% of the variability in mosquito abundance. The water content of snowpack measured within the Kern River watershed during winter explained 70% of the variation in average mosquito abundance during the following summer. After being absent from Kern County since 1983, western equine encephalomyelitis virus (WEE) returned during the wet years of 1996-98 after the flow of the Kern River exceeded 150,000 acre-ft (450 hectare-meters) per month. Water content of snow in the Sierra Nevada during winter provided an excellent early warning of vernal river runoff, mosquito abundance, and enzootic WEE activity levels on the floor of the San Joaquin Valley.
1990 - 1998年期间，加利福尼亚州克恩县夏季丰富的致倦库蚊数量与降雨量、积雪深度、含水量以及克恩河的径流量存在定量关系。冬季的总月降雨量滞后4 - 6个月，仅解释了夏季每个诱捕夜每月采集到的宿主寻找雌蚊数量变化的13%。相比之下，回归分析表明，提前1个月的河流径流量解释了蚊子数量变化的67%。冬季在克恩河流域内测量的积雪含水量解释了次年夏季平均蚊子数量变化的70%。自1983年以来一直未在克恩县出现的西部马脑炎病毒（WEE），在1996 - 1998年的湿润年份，当克恩河流量超过每月15万英亩 - 英尺（450公顷 - 米）后再次出现。冬季内华达山脉的积雪含水量为圣华金谷谷底的春季河流径流量、蚊子数量以及WEE地方性活动水平提供了极佳的早期预警。
