LEGIONELLA - World Health Organization

of the impact Legionnaires’ disease can have on tourism, the priority may be greater than local
morbidity and mortality suggests. The chapter provides information on surveillance systems;
it also gives guidance on policies and practice for outbreak management, and on institutional
roles and responsibilities when an outbreak control team is convened.
Chapter 10 considers regulatory aspects of controlling Legionella in water systems and preventing
legionellosis. Disease notification systems provide the basis for initiating investigations,
identifying sources of infection, issuing public advice and limiting the scale and recurrence
of outbreaks. Notification and investigation systems can be incorporated within regulations,
which generally have a number of common features. The chapter also gives guidance on designing
new regulations, emphasizing the key features that need to be considered, such as managerial
responsibilities; registration and notification; system assessment and design; operational
monitoring and verification; documentation of management plans and record keeping; and
surveillance and audit. It also covers inclusion of specific regulations to deal with responses to
outbreaks.
Chapter 11 covers laboratory aspects. Accurate diagnosis of Legionella is important, because timely
and appropriate therapy is the key to improving patient outcomes. The chapter reviews the
five methods currently used for the laboratory diagnosis of Legionella infections — isolation
of the organism on culture media, paired serology, detection of antigens in urine, demonstration
of the bacterium in tissue or body fluids using immunofluorescence microscopy, and detection
of bacterial deoxyribonucleic acid (DNA) using the polymerase chain reaction.
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