La experiencia con la influenza de Hong Kong en Zonas Tropicales

Abstract

Following the introduction of A2/Hong Kong/68 influenza virus into 2 different susceptible populations residing in Thailand and the Panama Cnal Zone, epidemic disease occurred within approximately 1 month. The estabishment 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 percent of US servicemen became ill, although 13 percent of them were infected. The epidemic progressed slowly, so that no more than 1.5 percent 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 percent, and subclinical infection occurred in 5 percent 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 realted 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 epiemiological patterns of disease in tropical areas, similar to those observed in ...(AU)

Publicado en inglés en el Bulletin World Health Organization 41 (3): 387-391, 1969