EID Journal Home > Volume 17, Number 4–April 2011
Volume 17, Number 4–April 2011
Legionella longbeachae and Legionellosis
Harriet Whiley and Richard Bentham
Author affiliation: Flinders University, Adelaide, South Australia, Australia
Suggested citation for this article
Reported cases of legionellosis attributable to Legionella longbeachae infection have increased worldwide. In Australia and New Zealand, L. longbeachae has been a known cause of legionellosis since the late 1980s. All cases for which a source was confirmed were associated with potting mixes and composts. Unlike the situation with other Legionella spp., L. longbeachae–contaminated water systems in the built environment that cause disease have not been reported. Spatially and temporally linked outbreaks of legionellosis associated with this organism also have not been reported. Sporadic cases of disease seem to be limited to persons who have had direct contact with potting soil or compost. Long-distance travel of the organism resulting in infection has not been reported. These factors indicate emergence of an agent of legionellosis that differs in etiology from other species and possibly in route of disease transmission.
Legionella spp. were first identified as organisms of public health significance in 1976 and are now recognized as the causative agent of legionellosis. L. pneumophila was the species responsible for this initial disease outbreak and has remained the major cause of legionellosis (1,2). The clinical manifestations of legionellosis range from no symptoms to acute atypical pneumonia and multisystem disease (2). The term legionellosis refers collectively to the clinical syndromes resulting from Legionella spp. infection, i.e., Legionnaires' disease (a Legionella spp.–derived pneumonic infection) and Pontiac fever (an acute, self-limited febrile illness that has been linked serologically and by culture to Legionella spp.) (1,2). Community- and hospital-acquired legionelloses typically are associated with water systems in the built environment, such as cooling towers, spas, showers, and other warm water systems (1,2). Protozoa play a major role in the multiplication and dissemination of Legionella spp. in natural environments. The parasitism of amoebae and ciliates is well documented, and this parasitic capability is the basis of human disease through infection of human lung macrophages (1,2).
L. longbeachae was first isolated in 1980 from a patient with pneumonia in Long Beach, California, USA (3). A second serogroup of L. longbeachae was discovered during the same year (4). Neither of these reports suggested a recognized source of infection.
In Europe, L. pneumophila is responsible for 95% of cases of Legionnaires' disease. Of the remaining 5%, the most common causative agent is L. longbeachae (5). In Australia, New Zealand, and Japan, reported cases of L. longbeachae infection occur as often as cases of L. pneumophila infection (6–8). Within the past decade, the number of L. longbeachae reports has increased markedly across Europe and parts of Asia (9–15).
L. longbeachae and Legionellosis | CDC EID
Suggested Citation for this Article
Whiley H, Bentham R. Legionella longbeachae and legionellosis. Emerg Infect Dis [serial on the Internet]. 2011 Apr [date cited].
Comments to the Authors
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Richard Bentham, School of the Environment, Environmental Health, Flinders University, PO Box 2100, Adelaide, SA 5001, Australia; email: firstname.lastname@example.org