埃及伊蚊对登革Ⅱ型病毒感染Balb/C实验小鼠的增强

Mosquito-induced enhancement of Dengue virus infection in mice

以Balb C小鼠为实验动物 ,探讨了埃及伊蚊Aedesaegypti唾液对登革病毒感染宿主的影响。结果显示 ,在皮下接种剂量相同的情况下 ,如果Balb C实验小鼠预先被一定数量的埃及伊蚊叮咬以后 ,实验小鼠感染病毒的程度有所提高 ,血清中的抗体滴度明显降低 ,腹腔巨噬细胞感染登革病毒的阳性率及感染的时间动态曲线也有明显差异 ,感染高峰期延迟。这些说明实验小鼠被媒介蚊虫叮咬以后变得相对容易被登革病毒感染 ,可能是媒介蚊虫叮咬小鼠时分泌的唾液对宿主的免疫反应系统有一定作用。因此可以初步肯定埃及伊蚊在登革病毒的感染传播过程中 ,影响了Balb C实验小鼠的免疫功能 。

Dengue fever (DF)/dengue haemorrhagic fever (DHF) is one of the most important human arbo virus infectious diseases in tropical and subtropical areas with increasing numbers of patients and the expansion of epidemic areas. Understanding the mechanisms of its infection and spread is the foundation for effective surveillance and control of this disease and its mosquito vector. The saliva secreted by feeding mosquitoes is not only the liquid vector of virus transmission, but can also enhance virus infection through immuno modulation of its vertebrate host.This paper reports experiments that sought to determine if the DEN 2 virus infection in Balb/C laboratory mice could be enhanced by the vector mosquito Aedes aegypti. After being bitten by a number of mosquitoes, mice were injected intravenously with defined titers of the DEN 2 virus. The differences in viremia, the titers of DEN 2 antibodies and the infection rates of macrophages in the abdominal cavities of these mice were observed and compared with those of mice that had only been injected with the DEN 2 virus. The results showed mice that had been bitten by vector mosquitoes were more easier infected with the DEN 2 virus; periods of viremia were extended from 1-2 days to 4 days, antibody titres dropped from 1∶64, 1∶96 to 1∶16 and 1∶32 respectively in the 4th and 7th days after injection while infection rates of macrophages varied over the first 7 days. These results indicate that vector mosquito bites can enhance the infection of mice with the DEN 2 virus.