Legionellosis classification

Legionellosis Microchapters
Home
Patient Information
Overview
Historical Perspective
Classification
Pathophysiology
Causes
Differentiating Legionellosis from other Diseases
Epidemiology and Demographics
Risk Factors
Natural History, Complications and Prognosis
Diagnosis
History and Symptoms
Physical Examination
Laboratory Findings
Chest X Ray
CT
Other Diagnostic Studies
Treatment
Medical Therapy
Prevention
Cost-Effectiveness of Therapy
Future or Investigational Therapies
Case Studies
Case #1
Legionellosis classification On the Web
Most recent articles
Most cited articles
Review articles
CME Programs
Powerpoint slides
Images
American Roentgen Ray Society Images of Legionellosis classification All Images X-rays Echo & Ultrasound CT Images MRI
Ongoing Trials at Clinical Trials.gov
US National Guidelines Clearinghouse
NICE Guidance
FDA on Legionellosis classification
CDC on Legionellosis classification
Legionellosis classification in the news
Blogs on Legionellosis classification
Directions to Hospitals Treating Legionellosis
Risk calculators and risk factors for Legionellosis classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Legionellosis may be classified into three types based upon the affected organ systems and the clinical presentation: pulmonary infection (Legionnaires' disease), extrapulmonary infection, and Pontiac fever. Legionellosis may also be classified based on the infectious species responsible for the disease.

Clinical Classification

Legionellosis may be classified into three types based upon affected organ systems and clinical presentation:

Pulmonary Infection (Legionnaires' Disease)

• Legionnaires' disease may further be classified into:

• Healthcare associated Legionnaires' disease
• Pittsburgh pneumonia

Extrapulmonary Legionella Infection

• The following organ systems may be involved:

• Cutaneous involvement legionellosis
• Legionella encephalopathy
• Disseminated legionella infection

Pontiac Fever

• A mild flu-like infectious disease without pneumonia. It is often distinguished from Legionnaires' disease by clinical features (see table below).

Characteristic	Legionnaires' disease	Pontiac fever
Clinical features	Pneumonia, cough, fever	Flu-like illness (fever, chills, malaise) without pneumonia
Radiographic pneumonia	Yes	No
Incubation period	2-14 days after exposure	24-72 hours after exposure
Etiologic agent	Legionella species	Legionella species
Attack rate[1]	< 5%	> 90%
Isolation of organism	Possible	Never
Outcome	Hospitalization common Case-fatality rate: 5-30%	Hospitalization uncommon Case-fatality rate: 0%

Microbiological Classification

Legionellosis may also be classified based on the infectious species responsible for the disease. Species of Legionella include:

• L. pneumophila
• L. feeleii
• L. sainthelensi