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目的通过实验,确定被SA14-14-2乙脑减毒活疫苗免疫的宿主动物和人在被媒介蚊虫叮咬后,是否存在感染和传播的可能。方法建立三带喙库蚊和致倦库蚊的实验室种群,用乙型脑炎SA14-14-2疫苗株病毒和乙脑野毒株经口感染两种库蚊,感染后不同时间取一定数量的蚊,研磨制成悬液,应用空斑试验方法检测感染后不同时间蚊体内的病毒存在情况和病毒滴度。结果在用6.06logPFU/mlSA14-14-2病毒经口感染的两种库蚊中,没有检测到病毒空斑,即没发现蚊虫的感染;在用较高的6.18logPFU/ml病毒经口感染的三带喙库蚊和致倦库蚊中,分别有一组蚊虫出现低滴度感染,空斑形成单位分别是1.24和1.11log10PFU/ml;在用野毒株经口感染的两种库蚊,共计19组蚊虫中,有14组发生感染,空斑形成单位在3.18~4.79log10PFU/ml。结论作为乙脑主要传播媒介的三带喙库蚊和致倦库蚊对SA14-14-2疫苗株病毒的经口感染和病毒在体内的复制严重受限,当叮咬接种疫苗的人后,不具备发生乙脑病毒感染和传播的能力。
Objectives To determine whether there is the possibility of infection and transmission of host animals and humans immunized with the live attenuated SA14-14-2 JE vaccine after being bitten by vector mosquitoes. Methods The laboratory population of Culex tritaeniorhynchus and Culex pipiens quinquefasciatus was established. Two species of Culex pipiens pallens were orally infected with vaccine strain of SA14-14-2 and Japanese encephalitis B virus. After inoculation, The number of mosquitoes, ground into a suspension, the use of plaque test method to detect the mosquitoes at different times after infection of the virus and virus titer. Results No virus plaques were detected in the two species of Culex pipiens that were orally infected with the 6.06 log PFU / ml SA14-14-2 virus, that is, no mosquito infection was found; in the case of oral infections with the higher 6.18 log PFU / ml virus Three Culex tritaeniorhynchus and Culex quinquefasciatus, respectively, a group of mosquitoes showed low titer infection, plaque forming units were 1.24 and 1.11log10PFU / ml; wild Culex pipiens pallens Among 19 groups of mosquitoes, 14 groups were infected with plaques forming units at 3.18-4.79log10 PFU / ml. CONCLUSIONS: Oral infections of the SA14-14-2 vaccine strain, Culex tritaeniorhynchus and Culex quinquefasciatus, the major vectors of JE, and the replication of the virus in vivo are severely limited, and after bite vaccination, Have the ability to produce JE virus infection and transmission.