Buescher E L, Smith T J, Zachary I H
Bull World Health Organ. 1969;41(3):387-91.
Following the introduction of A2/Hong Kong/68 influenza virus into 2 different susceptible populations residing in Thailand and the Panama Canal Zone, epidemic disease occurred within approximately 1 month. The establishment and transmission of the virus, and the disease it caused, were studied in detail. The rates of progression and extent of overt epidemic disease and the proportions of overt to subclinical infection in the 2 areas were different. In Korat Royal Thai Air Force Base, only 8% of US servicemen became ill, although 13% of them were infected. The epidemic progressed slowly, so that no more than 1.5% of the population were ill at any one time during the 3 months of its recognized presence. In contrast, in the Canal Zone the clinical attack rate approached 50%, and subclinical infection occurred in 5% or less of the population during a 6-week period when absenteeism from schools and work was quite obvious. Factors such as immunization status of the populations and virulence of virus seemed not to be primarily responsible for the differences. Rather, the latter appear to be related to differences in environmental circumstances, with crowding contributing to the higher disease incidence in the Canal Zone.The data show that this variant A2 virus may produce different epidemiological patterns of disease in tropical areas, similar to those observed in temperate zones.
在将A2/香港/68流感病毒引入居住在泰国和巴拿马运河区的两个不同易感人群后，大约1个月内发生了流行病。对该病毒的建立、传播及其引发的疾病进行了详细研究。两个地区明显的流行病的进展速度、程度以及显性感染与亚临床感染的比例有所不同。在呵叻泰国皇家空军基地，只有8%的美国军人患病，尽管其中13%受到了感染。疫情进展缓慢，在其被确认存在的3个月期间，任何时候患病的人口比例都不超过1.5%。相比之下，在运河区，临床发病率接近50%，在6周期间，学校和工作缺勤情况十分明显，亚临床感染发生在5%或更少的人口中。人群的免疫状态和病毒毒力等因素似乎不是造成这些差异的主要原因。相反，后者似乎与环境情况的差异有关，拥挤导致运河区疾病发病率较高。数据表明，这种变异的A2病毒在热带地区可能产生与温带地区观察到的类似的不同疾病流行模式。
