LEGIONELLA - World Health Organization

Symptoms
The clinical manifestations of extrapulmonary Legionella infections are often dramatic. Legionella
have been implicated in cases of sinusitis, cellulitis, pancreatitis, peritonitis and pyelonephritis,
most often in immunocompromised patients (Eitrem, Forsgren & Nilsson, 1987; Stout &
Yu, 1997). Lowry & Tompkins (1993) reported 13 extrapulmonary infections, including
brain abscesses and sternal wound infections. The most commonly affected site is the heart
(e.g. myocarditis, pericarditis, postcardiomyotomy syndrome and endocarditis) (Stout & Yu,
1997). Endocarditis due to Legionella spp. has been cited in only a few publications, and in
all reported cases patients had a prosthetic valve (McCabe et al., 1984; Tompkins et al., 1988;
Chen, Schapiro & Loutit, 1996). The patients showed low-grade fever, night sweats, weight
loss, malaise, symptoms of congestive heart failure, and vegetation on echocardiography
(Brouqui & Raoult, 2001). Legionella rarely spreads into the nervous system; more frequently,
it leads to neurological manifestations of encephalomyelitis, cerebellum involvement and
peripheral neuropathy (Shelburne, Kielhofner & Tiwari, 2004). Legionella meningoencephalitis
may mimic the symptoms of herpes encephalitis (Karim, Ahmed & Rossoff, 2002).
Diagnosis
Legionellosis should be considered in the differential diagnosis of patients showing a combination
of neurological, cardiac and gastrointestinal symptoms, particularly in the presence of radiographic
pneumonia (Shelburne, Kielhofner & Tiwari, 2004).
Causative agent
Among the four species of Legionella responsible for extrapulmonary infections, L. pneumophila
was the most commonly isolated bacteria (Lowry & Tompkins, 1993).
LEGIONELLA AND THE PREVENTION OF LEGIONELLOSIS