Effects of initial dose on eastern equine encephalomyelitis virus dependent mortality in intrathoracically inoculated Culiseta melanura (Diptera: culicidae)
Effects of initial dose on eastern equine encephalomyelitis virus dependent mortality in intrathoracically inoculated Culiseta melanura (Diptera: culicidae)
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DOI：
10.1603/0022-2585-37.6.815
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发表时间：
2000-11-01
影响因子：
2.1
通讯作者：
Scott, TW
中科院分区：
文献类型：
--
作者：
Cooper, LA;Sina, BJ;Scott, TW
有利于快速和大量病毒粒子产生的病毒生长特征可能会增加病毒传播，但对受感染的宿主有害。包括东部马脑脊髓炎（EEE）病毒在内的几种虫媒病毒会对受感染蚊媒的生存产生负面影响。为了检验 EEE 病毒的蚊子毒力特性是由病毒内在生长特性的存在引起的假设，我们研究了感染剂量对胸腔内接种的 Culiseta melanura (Coquillett) 存活的影响。对每只蚊子接种 10(1.5) 噬菌斑形成单位 (PFU) 的低初始剂量或每只蚊子 10(5.5) PFU 的高初始剂量的年龄匹配雌性进行 8 周的每日存活率监测。与接种稀释剂的对照组相比，两个剂量组的蚊子的存活率均显着降低。两个感染组之间的每日生存率没有显着差异。通过在接种后 96 小时内每 12 小时采样一次蚊子来评估已接种蚊子内的病毒产量。两个剂量组均出现病毒快速扩增，并且在暴露后 24 小时，接种低剂量的蚊子的平均病毒载量与接种高剂量的蚊子相当。同样，虽然可检测到的病毒粒子更快地出现在高剂量蚊子的唾液中，但到接种后 72 小时，两个暴露组之间没有检测到病毒传播的显着差异。这些结果表明，EEE 病毒对其北美地方性蚊子媒介的毒力不依赖于剂量，并且可能反映了该病毒在受感染蚊子内的固有生长动力。
Viral growth characteristics that favor rapid and prodigious virion production may increase virus transmission but be detrimental to infected hosts. Several arboviruses, including eastern equine encephalomyelitis (EEE) virus, negatively affect the survival of their infected mosquito vectors. To test the hypothesis that the mosquito virulent properties of EEE virus are caused by the presence of intrinsic viral growth properties, we investigated the effects of infecting dose on the survival of intrathoracically inoculated Culiseta melanura (Coquillett). Daily survival of age-matched females inoculated with either a low initial dose of 10(1.5) plaque-forming units (PFUs) per mosquito or a high initial dose of 10(5.5) PFUs per mosquito was monitored for 8 wk. Compared with diluent inoculated controls, mosquitoes from both dosage groups displayed highly significant decreases in survival. No significant differences in daily survival were detected between the two infected groups. Virus production within inoculated mosquitoes was assessed by sampling mosquitoes every 12 h for 96 h after inoculation. Rapid virus amplification occurred in both dosage groups, and by 24 h after exposure the mean viral loads in mosquitoes inoculated with the low dose were comparable to those inoculated with the high dose. Likewise, although detectable virions appeared sooner in the saliva of high dosage mosquitoes, by 72 h after inoculation no significant differences in virus transmission were detected between the two exposure groups. These results indicate that the virulence of EEE virus for its enzootic North American mosquito vector is not dosage dependent and likely reflects the inherent growth propel-ties of this virus within infected mosquitoes.