| Phenotype/Symptom | Type | Frequency | Severity | HPO Term suggestion |
|---|---|---|---|---|
| Fever | Symptom | Common; high fever is a typical presentation of Legionnaires’ disease (pqac-00000032, pqac-00000034) | Moderate to severe | Fever (HP:0001945) |
| Cough | Symptom | Common in pneumonic disease (pqac-00000034) | Mild to severe | Cough (HP:0012735) |
| Dyspnea / shortness of breath | Symptom | Common in pneumonia; may progress to respiratory failure in severe cases (pqac-00000019, pqac-00000034, pqac-00000035) | Moderate to severe | Dyspnea (HP:0002094) |
| Pneumonia | Clinical sign / syndrome | Core manifestation; Legionnaires’ disease is the pneumonic form of legionellosis (pqac-00000019, pqac-00000022, pqac-00000035) | Severe; ICU admission occurs in approximately one-third of cases (pqac-00000005) | Pneumonia (HP:0002090) |
| Diarrhea | Symptom | Frequently reported extrapulmonary/non-specific feature (pqac-00000032, pqac-00000033) | Mild to moderate | Diarrhea (HP:0002014) |
| Hyponatremia | Laboratory abnormality | Commonly associated non-specific laboratory finding (pqac-00000032, pqac-00000033) | Mild to moderate; may mark systemic severity | Hyponatremia (HP:0002902) |
| Rhabdomyolysis / elevated creatine kinase | Laboratory abnormality / complication | Uncommon but well-documented association; elevated CK reported in severe disease (pqac-00000032, pqac-00000033) | Severe when present | Rhabdomyolysis (HP:0003201) |
| Acute kidney injury | Complication / laboratory abnormality | Very common in severe ICU cases; nearly 80% of adults with ICU Legionella pneumophila infection in one 10-year cohort developed AKI, about half requiring renal replacement therapy (pqac-00000033) | Severe | Acute kidney injury (HP:0001919) |
| Confusion / acute confusion / encephalopathy | Symptom / neurologic sign | Common neurologic manifestation in severe disease; acute confusion highlighted in clinical presentation (pqac-00000032) | Moderate to severe | Encephalopathy (HP:0001298) |
| Elevated C-reactive protein | Laboratory abnormality | Common inflammatory marker elevation in severe disease (pqac-00000032) | Mild to severe | Elevated C-reactive protein level (HP:0011227) |
| Lymphopenia | Laboratory abnormality | Reported in severe disease with hyperleukocytosis and lymphopenia (pqac-00000032) | Mild to moderate | Lymphopenia (HP:0001888) |
| Liver involvement / hepatic involvement | Organ involvement / lab abnormality | Documented extrapulmonary manifestation; may include liver involvement and abnormal liver tests (pqac-00000032) | Mild to severe | Abnormality of the liver (HP:0001392) |
| Relative bradycardia | Clinical sign | Reported as a characteristic clue in Legionnaires’ disease (pqac-00000032) | Mild to moderate | Bradycardia (HP:0001662) |
| Pancreatitis | Complication / extrapulmonary manifestation | Rare but reported extrapulmonary manifestation (pqac-00000032) | Severe | Pancreatitis (HP:0001733) |
| Myocarditis / pericarditis | Complication / extrapulmonary manifestation | Rare but documented cardiovascular extrapulmonary manifestation (pqac-00000032) | Severe | Myocarditis (HP:0012819) / Pericarditis (HP:0012810) |


*Table: This table summarizes major clinical manifestations and laboratory abnormalities reported for Legionnaires’ disease, including common pneumonia features and severe extrapulmonary complications. It highlights phenotype types, approximate frequency patterns, severity, and suggested HPO mappings for knowledge base annotation.*