Legionellosis Outbreaks Associated with Two Hotels — U.S. Virgin Islands, October 2024–April 2025

Legionellosis is a bacterial disease caused by inhalation or aspiration of Legionella bacteria; Legionnaires disease is a type of legionellosis characterized by illness with pneumonia.During November 2024, the U.S. Virgin Islands (USVI) Department of Health (VIDOH) was notified of two confirmed Legionnaires disease cases among travelers to two different hotels on St. Croix Island.VIDOH investigated to determine exposure sources and prevent additional cases.Two additional legionellosis cases were identified.The four patients with cases were aged 53-73 years; two patients were hospitalized and none died.At hotel A, L. pneumophila was detected in three of 21 (14%) environmental samples.VIDOH required hotel A to close one guest room, remediate, and retest.At hotel B, L. pneumophila was detected in 22 of 40 (55%) samples.VIDOH required hotel B to cease hotel operations until remediation and retesting were completed.L. pneumophila was isolated from shower samples at both hotels, in the cistern and cold water system at hotel A, and in cold and hot water systems at hotel B. The two USVI outbreaks underscore the importance of reporting legionellosis among returned travelers to facilitate local public health investigations and prevent additional cases.In addition, in tropical climates, cold water systems operate at temperatures favorable for Legionella growth (77°F-113°F [25°C-45°C]), highlighting the importance of effective water management programs and water system disinfection to prevent disease spread. Investigation and Results Hotel AOn November 6, 2024, CDC notified VIDOH of a case of Legionnaires disease confirmed by a urinary antigen test (UAT) in a man aged 73 years (patient 1); Council of State and Territorial Epidemiologists case definitions for legionellosis were used.On October 30, the patient developed fever, shortness of breath, body aches, joint pain, neck pain, loss of appetite, and diarrhea.He was hospitalized in his U.S. state of residence after returning from travel to St. Croix Island and recovered.He reported staying in two guest rooms at hotel A during October 21-29.During the investigation of patient 1, a case of probable legionellosis was identified in a woman aged 71 years (patient 2).