Harlem Legionnaires' Outbreak Hospitalizes 90, Kills 7 as US Case Rate Hits 2.5 per 100,000
Updated
Updated · The Conversation · Jun 19
Harlem Legionnaires' Outbreak Hospitalizes 90, Kills 7 as US Case Rate Hits 2.5 per 100,000
3 articles · Updated · The Conversation · Jun 19
Summary
Harlem’s 2025 Legionnaires’ outbreak left 90 people hospitalized and seven dead, the latest major US cluster of the severe pneumonia-like disease.
Legionella spreads when bacteria multiply in water systems such as cooling towers, hot water tanks and plumbing, then become airborne in droplets that people inhale rather than passing person to person.
US incidence has climbed to about 2.5 confirmed cases per 100,000 people annually — a fivefold increase since 2000 — with cases peaking in warm, humid weather or after rain.
Past outbreaks show the risk persists despite better controls, including 138 cases and 16 deaths in the South Bronx in 2015 and 188 illnesses with 21 deaths at a 1999 Dutch flower show.
Hospitals, hotels, cruise ships and office buildings now routinely monitor for Legionella, while rapid urine tests and newer antibiotics such as azithromycin or levofloxacin have improved detection and treatment.