A STUDY OF RESPIRATORY-INFECTIONS IN A HEALTHY ADULT-POPULATION DURING THE 1987 AUSTRALIAN WINTER

During the 1987 Australian winter, respiratory illness patterns were s tudied in a population of 454 healthy adults, aged 18-59, over a perio d of 45 days. These patterns were matched with data obtained from labo ratory diagnoses for respiratory viruses, Mycoplasma pneumoniae and ba cteria. Influenza B/1 /86 was by far the most prevalent pathogen but o ther viruses including influenza A, paramyxoviruses, respiratory syncy tial virus and coronavirus OC-43 were also present, either alone or in combination during the sampling period. Overall, 92 males and 101 fem ales experienced one episode, 12 males and 22 females experienced two episodes and four females experienced three episodes. However, there w ere only 52 instances of viral or M. pneumoniae infections, of which 3 7 had a defined aetiology, while the remainder were clinically silent. No bacterial pathogens could be detected from throat swabs taken from 15 of 37 volunteers in whom a viral infection was detected, or from 4 3 of 70 volunteers who did not experience such infections. The study i ndicates that major deficiencies in our understanding of the aetiology of respiratory viral illness are probably due to methodological probl ems in obtaining laboratory diagnoses for many respiratory viruses, an d that great difficulties exist in establishing an aetiology for respi ratory infections based upon clinical symptoms alone.