Lee J H, Rowley W A, Platt K B
Department of Entomology, Iowa State University, Ames 50011-3222, USA.
J Med Entomol. 2000 Jan;37(1):187-93. doi: 10.1603/0022-2585-37.1.187.
The longevity of an Iowa strain of Culex tarsalis Coquillett fed blood meals containing 2 concentrations of western equine encephalomyelitis virus from Iowa (WEE-7738) was compared with that of Cx. tarsalis fed blood without virus. Females exposed to 4.7-5.0 log TCID50 per mosquito of WEE-7738 did not live as long as mosquitoes exposed to 2.7-3.0 log TCID50 per mosquito or controls. Only 1% of mosquitoes fed blood containing the higher virus concentration survived to day 18 after exposure. However, 13% of mosquitoes fed blood with the lower virus titer and 19.5% of the controls were still alive on day 18 after exposure. Flight activity scores of Cx. tarsalis infected with 4.7-5.0 log TCID50 per mosquito of WEE-7738 were 27.5% lower, and there were 26.1% fewer spontaneous flights than noninfected controls from days 6-11 after infection. After day 8 after infection, infected Cx. tarsalis had 37.1% lower activity scores and 40.0% fewer spontaneous flights than noninfected controls. Virus infection did not affect how long a mosquito flew in a 24-h period (the daily flying time) or the duration of individual flights. The spontaneous flight activity pattern (circadian rhythm) of infected mosquitoes was identical to those of controls. Both infected and noninfected mosquitoes began spontaneous flight activity at 2000-2100 hours (CST) and were active throughout the entire dark phase of the 24-h cycle. Although mosquitoes were active throughout the night, there was a burst or peak of activity between 2200 and 2300 hours when the complete dark cycle began. These results indicate that the adverse effect of WEE infection on longevity and spontaneous flight activity of Cx. tarsalis may decrease vectorial capacity of Cx. tarsalis for WEE.
将含有两种浓度来自爱荷华州的西部马脑炎病毒（WEE - 7738）的血餐喂食给爱荷华州品系的致倦库蚊（Culex tarsalis Coquillett），并将其寿命与喂食不含病毒血液的致倦库蚊进行比较。暴露于每只蚊子含4.7 - 5.0 log TCID50的WEE - 7738的雌性蚊子，其存活时间不如暴露于每只蚊子含2.7 - 3.0 log TCID50的蚊子或对照组。暴露后，仅1%喂食含较高病毒浓度血液的蚊子存活至第18天。然而，暴露后第18天，喂食含较低病毒滴度血液的蚊子中有13%仍然存活，对照组中有19.5%仍然存活。每只蚊子感染4.7 - 5.0 log TCID50的WEE - 7738的致倦库蚊，在感染后第6 - 11天，其飞行活动得分比未感染对照组低27.5%，自发飞行次数少26.1%。感染后第8天之后，感染的致倦库蚊活动得分比未感染对照组低37.1%，自发飞行次数少40.0%。病毒感染并未影响蚊子在24小时内飞行的时长（每日飞行时间）或单次飞行的持续时间。感染蚊子的自发飞行活动模式（昼夜节律）与对照组相同。感染和未感染的蚊子均在2000 - 2100小时（中部标准时间）开始自发飞行活动，并在24小时周期的整个黑暗阶段保持活跃。尽管蚊子在整个夜间都活跃，但在2200至2300小时之间，即完整黑暗周期开始时，会出现活动高峰。这些结果表明，WEE感染对致倦库蚊寿命和自发飞行活动的不利影响可能会降低致倦库蚊传播WEE的媒介能力。
