The Etiology of Respiratory Tract Infections in a Tropical Country1

Olson, L. C. (Rockefeller Foundation, G.P.O. Box 2453, Bangkok, Thailand), U. Lexomboon, P. Sithisarn and H. E. Noyes. The etiology of upper respiratory tract infections in a tropical country. Am J Epidemiol 97: 34-43, 1973. —Upper respiratory tract infections were studied in 477 children living in Bangkok, Thailand, during January 1968 to March 1969. A presumptive viral etiology was established in 40% of the patients. In those patients in whom a specific virus could be identified, illness was associated with parainfluenza virus in 40% and with respiratory syncytial virus and adenoviruses each in 13%. Other viruses appeared to make a less significant overall contribution and included rhinovirus, rubella virus, and coxsackie B2 virus. The 1968 Hong Kong A influenza virus variant appeared during August 1968, and completely dominated as the identifiable cause of infection during the next 2 months. Age-specific antibody prevalence data suggest that many respiratory viruses circulate efficiently through the population. Periods when specific agents were prevalent were independent of season. This was not unexpected since weather conditions, insofar as they effect the living habits of the community, were essentially uniform throughout the study period.