Incidence of Legionella in the urban environment in Australia

Abstract

Extensive sampling of the built environment was undertaken to determine the extent of Legionella presence in different regions of New South Wales. Distribution and abundance of Legionella in N.S.W. were found to be similar to those found in Europe and North America, despite Australia's warmer climate and geographical isolation. Air conditioning cooling towers, warm water systems and spas showed the highest incidence of Legionella (32, 37 and 36%, respectively). Legionella pneumophila serotypes predominated, being present in 82% of the positive samples examined. Seasonality in isolation patterns was not detected. The Illawarra Health Region, where a major outbreak has recently occurred, was found to have the lowest incidence of Legionella, probably due to improved maintenance measures undertaken in the aftermath of the outbreak. It was concluded that the distribution and abundance of Legionella in the south-eastern part of Australia follows a comparable pattern to elsewhere in the world and that measures to prevent outbreaks of Legionnaires' disease should be similar to those currently being introduced in the U.S.A. and Great Britain.