Department of Infectious Disease Control, Faculty of Medicine, Oita University, Oita 879-5593, Japan.
Parasit Vectors. 2014 Mar 31;7:143. doi: 10.1186/1756-3305-7-143.
Dengue virus infection manifests in three distinct forms in humans: dengue fever, dengue hemorrhagic fever, and dengue shock syndrome. Infection with the virus is a fatal disease; no vaccine is available and prevention depends on interruption of the chain of transmission. The study of dengue viral transmission by mosquitoes is hindered due to the lack of an affordable animal model. In general, immuno-competent mice are used as a simple and inexpensive animal model, but mice are not susceptible to dengue virus infection and therefore viremia will not occur following the inoculation of the virus in such mice. Here, we report a method for creating artificial viremia in immuno-competent mice, and further demonstrate the use of viremic mice to simultaneously infect a large number of Aedes aegypti.
We infected K562 cells with DENV-2 in the presence of an antibody against DENV-4. We then incubated the cells for 2 d before injecting the infected cells into C3H mice. After 5 h incubation, we allowed 100-150 female Aedes aegypti to feed on blood from the mice directly. We collected blood samples from the mice and from randomly selected Ae. aegypti at 2, 6, 12, and 24 h post-blood meal and screened the samples for DENV-2 genome as well as for virus concentration.
Our procedure provided high virus concentrations in the mice for at least 7 h after viral inoculation. We found that 13 out of 14 randomly picked mosquitoes were infected with DENV-2. High concentrations of virus were detected in the mosquitoes until at least 12 h post-infection.
Using the viremic immuno-competent mouse, we show that mass infection of Ae. aegypti is achievable. Compared to other infection techniques using direct inoculation, membrane-feeding, or immuno-deficient/humanized mice, we are confident that this method will provide a simpler and more efficient infection technique.
登革病毒感染在人类中表现为三种不同的形式：登革热、登革出血热和登革休克综合征。感染该病毒是一种致命的疾病；目前尚无疫苗可用，预防取决于中断传播链。由于缺乏负担得起的动物模型，蚊子传播登革病毒的研究受到阻碍。一般来说，免疫功能正常的小鼠被用作简单而廉价的动物模型，但小鼠不易感染登革病毒，因此在给此类小鼠接种病毒后不会发生病毒血症。在这里，我们报告了一种在免疫功能正常的小鼠中制造人工病毒血症的方法，并进一步证明了使用病毒血症小鼠同时感染大量埃及伊蚊的方法。
我们在存在抗登革热病毒 4 型抗体的情况下，用 DENV-2 感染 K562 细胞。然后，我们将细胞孵育 2 天，然后将感染的细胞注射到 C3H 小鼠中。孵育 5 小时后，我们让 100-150 只雌性埃及伊蚊直接吸食来自小鼠的血液。我们从感染后的小鼠和随机挑选的埃及伊蚊中采集血液样本，在血餐 2、6、12 和 24 小时后检测 DENV-2 基因组和病毒浓度。
我们的方案在病毒接种后至少 7 小时内为小鼠提供了高病毒浓度。我们发现，随机挑选的 14 只蚊子中有 13 只感染了 DENV-2。在感染后至少 12 小时内，蚊子中仍能检测到高浓度的病毒。
我们使用带病毒血症的免疫功能正常的小鼠表明，埃及伊蚊的大规模感染是可以实现的。与其他使用直接接种、膜喂养或免疫缺陷/人源化小鼠的感染技术相比，我们相信这种方法将提供一种更简单、更有效的感染技术。
