Calisher C H, Sasso D R, Sather G E
Appl Microbiol. 1973 Oct;26(4):485-8. doi: 10.1128/am.26.4.485-488.1973.
During 1971, an epizootic of Venezuelan equine encephalitis (VEE) reached the United States. Laboratory tests were performed on a large number of sick, healthy, unvaccinated, and vaccinated horses. Neutralization (N) tests in cell cultures revealed that 153 of 193 (79.3%) equines outside the state of Texas and 175 of 204 (85.8%) within Texas (82.6% overall) had detectable N antibody to VEE virus a week or more after vaccination. Twenty-six of 40 (65%) non-Texas equines and 18 of 29 (62%) Texas equines which had no detectable antibody against VEE virus a week or more after vaccination had N antibody against Eastern equine encephalitis (EEE) or Western equine encephalitis (WEE) virus or both, whereas only 50 of 153 (32.7%) non-Texas equines and 82 of 175 (46.9%) Texas equines with demonstrable N antibody against VEE also had N antibody against EEE and/or WEE virus. In vaccinated equines, significant negative correlations were found between the occurrence of antibody to VEE and antibody to EEE and/or WEE virus. These findings support the hypothesis that pre-existing antibody to EEE and/or WEE virus may modify or interfere with infection by VEE virus. The epizoologic significance of this possibility is discussed briefly.
1971年期间，一场委内瑞拉马脑炎（VEE） epizootic蔓延至美国。对大量患病、健康、未接种疫苗和接种过疫苗的马匹进行了实验室检测。细胞培养中的中和（N）试验显示，在得克萨斯州以外的193匹马中，有153匹（79.3%），在得克萨斯州内的204匹马中有175匹（85.8%）（总体为82.6%）在接种疫苗一周或更长时间后对VEE病毒有可检测到的N抗体。在接种疫苗一周或更长时间后对VEE病毒无可检测抗体的40匹非得克萨斯州马匹中有26匹（65%），以及29匹得克萨斯州马匹中有18匹（62%）对东部马脑炎（EEE）或西部马脑炎（WEE）病毒或两者有N抗体，而在对VEE有可证实的N抗体的153匹非得克萨斯州马匹中只有50匹（32.7%），以及175匹得克萨斯州马匹中有82匹（46.9%）也对EEE和/或WEE病毒有N抗体。在接种疫苗的马匹中，发现VEE抗体的出现与EEE和/或WEE病毒抗体之间存在显著的负相关。这些发现支持了这样一种假设，即预先存在的EEE和/或WEE病毒抗体可能会改变或干扰VEE病毒的感染。简要讨论了这种可能性的流行病学意义。
