How important is vertical transmission in mosquitoes for the persistence of dengue? Insights from a mathematical model
How important is vertical transmission in mosquitoes for the persistence of dengue? Insights from a mathematical model
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DOI：
10.1016/j.epidem.2010.01.001
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发表时间：
2010-03-01
期刊：
影响因子：
3.8
通讯作者：
Boots, Michael
中科院分区：
文献类型：
--
作者：
Adams, Ben;Boots, Michael
在许多地区，登革热发病率随季节波动，在不利时期报告的感染病例很少。据推测，蚊子种群内的垂直传播使病毒在这些时候持续存在。文献综述表明，垂直感染效率为1- 4%。使用一个数学模型，我们认为，在这些感染率垂直传播是不是一个重要因素，长期的病毒持久性。在地方性流行情况下，只有当垂直感染效率超过20- 30%时，疾病的繁殖数量、半衰期和持续时间才显著增加。在流行病情况下，垂直感染加速了爆发的过程，实际上可能减少持续时间。这些结果源于这样一个事实，即蚊子的生命周期相对较快，垂直获得的感染在每一代中都被成倍稀释。当垂直感染的效率像经验研究报告的那样低时，病毒就会迅速消失，除非在人群中定期扩增。因此，无症状人类登革热病例等过程在持久性方面比在病媒群体内传播更可能具有重要意义。然而，经验数据并不明确，我们确定了几个研究领域，将进一步阐明垂直传播在登革热流行病学中的作用。(C)2010年爱思唯尔B。V.保留所有权利。
In many regions dengue incidence fluctuates seasonally with few if any infections reported in unfavourable periods. It has been hypothesized that vertical transmission within the mosquito population allows the virus to persist at these times. A review of the literature shows that vertical infection efficiencies are 1-4%. Using a mathematical model we argue that at these infection rates vertical transmission is not an important factor for long term virus persistence. In endemic situations, increases in reproductive number, half-life and persistence times of the disease only become significant when vertical infection efficiency exceeds 20-30%. In epidemic situations vertical infection accelerates the course of the outbreak and may actually reduce persistence time. These results stem from the fact that the mosquito life-cycle is relatively rapid and vertically acquired infections are multiplicatively diluted with every generation. When the efficiency of vertical infection is as low as reported from empirical studies, the virus is rapidly lost unless there is regular amplification in the human population. Processes such as asymptomatic human dengue cases are therefore more likely to be important in persistence than transmission within the vector population. The empirical data are not, however, unequivocal and we identify several areas of research that would further clarify the role of vertical transmission in the epidemiology of dengue. (C) 2010 Elsevier B. V. All rights reserved.