西安市流行性乙型脑炎流行病学特征分析

利用传染病报告系统报告数据和生物媒介监测,分析西安市流行性乙型脑炎(乙脑)的流行情况、宿主仔猪病毒感染率和生物媒介蚊子密度。西安市乙脑1951—1984年期间发病率为8.80/10万,1984年计划免疫实施后发病率开始呈大幅度下降趋势,80年代平均3.78/10万,90年代平均2.62/10万,2001—2007年期间发病率平均0.39/10万,呈明显阶段下降趋势。生物媒介显示西安蚊虫以淡色库蚊为主,仔猪乙脑病毒感染率较低。防止乙脑应采取提高接种率、灭蚊和加强乙脑疾病监测系统的综合性预防措施。     

Potential use of attenuated langat E5 virus as a live vaccine -- long term protection against Russian spring-summer encephalitis virus in mice

A single inoculation of Langat E5 virus provides 90-100% protection in mice against 3200-16000 lethal doses of Russian Spring-Summer Encephalitis (RSSE) virus when challenged 18 or 24 months later. The observed protection is found in the absence of neutralizing antibody (NA) against RSSE virus at the time of challenge but is associated with anamnestic NA response. Immunized mice have low titer short duration viremia. Immunized mice have late first detection and much lower multiplication in the brains, even though traces of virus could be detected in the brain up to 3 weeks following challenge. The observed protection results from sensitization due to immunization and quick host response following RSSE challenge resulting in significantly altered viral pathogenesis. Long term cross protection studies reported in this study and before coupled with the experience of the use of attenuated Langat E5 virus in humans volunteers suggests to its further testing as a live vaccine for prophylaxis against various members of Russian Spring-Summer virus complex throughout the world.     

Subpopulation of peripheral blood lymphocytes in human encephalitis caused by group B arboviruses (Dengue, West Nile and Japanese B encephalitis.

Sera from twenty patients with clinically diagnosed viral encephalitis were studied during the acute and convalescent phases of illness for evidence of group B arboviral infection by demonstrating a rise in the titre of haemagglutination inhibiting (HI) antibodies. The immune status of these individuals was studied by quantitating peripheral T, T and 'null' lymphocytes. The percentage of total T cells in arboviral encephalitic (AE) group decreased significantly while that of B cells and 'active' T cells remained unaltered when compared to that of normal individuals. The null cell percentage, on the other hand increased significantly in the AE group. The absolute number of circulating T and B cells did not alter in the AE group while that of null cells rose significantly. The percentage and concentration of T. B and null cells during the convalescent phase of AE did not differ significantly when compared to those of the acute phase.