Legionellosis results from infection by a group of bacteria named
Legionella.
Many different species of Legionella are commonly found in the
environment, some of which are known to cause illness in
people.
In Tasmania, legionellosis is mainly caused by
Legionella pneumophila and Legionella longbeachae. Infection
with Legionella pneumophila is called Legionnaires’ disease.
Symptoms of legionellosis include fever, cough, breathlessness, chest
pain and diarrhoea. Legionella generally infects the lung (pneumonia) which
often results in severe illness. Legionellosis is a disease of the middle-aged
and elderly. Men are affected more frequently than
women.
Legionellosis is usually diagnosed by a series of blood tests.
Occasionally, the organism can be grown from a sample of sputum or lung fluid.
Legionella pneumophila infection may also be identified rapidly by testing a
sample of urine.
Legionella pneumophila are commonly found in water and have been
isolated from hot water systems, air-conditioning cooling towers, hot and cold
water taps and showers. The bacteria must be inhaled to cause disease.
Legionnaires' disease occurs most commonly in the warmer months. Cigarette
smoking, heavy alcohol use, other illness or stress increase the risk of this
disease.
Incubation
period
2-10 days, usually 5-6 days.
Infectious
period
Person-to-person spread does not occur.
Control of
spread
Exclusion from work is not necessary.
Legionella from natural sources can enter and colonise manufactured
water systems such as water cooling systems incorporating cooling towers or
evaporative condensers; airhouses, hot and warm water supply services; spa
pools, spa baths and hydrotherapy pools; humidifiers and nebulisers and
decorative fountains. Inhalation of aerosols generated by these systems can
serve as a route of infection. These systems must be maintained according to
national guidelines which reduce the risk of them growing Legionella and
releasing them into the surrounding environment.
Treatment
Antibiotic treatment prescribed by the attending doctor. Severe cases
may need to be treated in hospital and may require intensive
care.
Legionella
pneumophila infection is a notifiable disease.
Adapted from "You’ve got What?", with the
permission of the Department of Human Services, South Australia.
For more
information visit http://www.dhhs.tas.gov.au/agency/pro/legionella/Index.php