A review of national legionellosis surveillance in Australia, 1991 to 2000.

A study was undertaken to analyse legionellosis notifications for the period 1991 to 2000 to establish the distribution of legionellosis in Australia with the aim of identifying risk factors amenable to public health intervention. Legionellosis notification rates ranged from 0.6 cases per 100,000 population in 1991 to 2.5 cases per 100,000 population in 2000. Notifications were highest in autumn (March to May). Sixty-nine per cent of cases were males. At-risk population included those aged over 50 years. The upward trend in notification rates of legionellosis indicated that this disease remains a significant public health problem particularly among older people. Seasonal differences in notification rates require further investigation to develop appropriate prevention and control strategies. To have a better understanding of the epidemiology of legionellosis, further information is needed on smoking history, chronic illnesses, whether the notification is outbreak-related and the species of Legionella isolated.