On February 1, 2022, the U.S. Virgin Islands Department of Health learned of a confirmed case of Legionnaires’ disease in a 55-year-old man from the mainland. He had flown home from a vacation in the islands on January 22 and fell ill the next day with a cough, shortness of breath and fatigue. On January 29 he was hospitalized for his breathing — and tested positive for COVID-19 on admission.
Because of his symptoms and his recent travel, doctors also ordered a urinary antigen test for Legionella pneumophila serogroup 1, which came back positive on January 31. He was treated for both COVID-19 pneumonia and Legionnaires’ disease — with remdesivir (stopped because of raised liver enzymes), the antibiotic levofloxacin, steroids, and an inhaler and expectorant as needed — and went home on February 2.
Timeline of the case and investigation, January–February 2022. Image from CDC’s page.
The rental house
The man had stayed at a privately owned vacation rental from January 15 to 22. Like most homes in the Virgin Islands, its drinking water came from rainwater collected in a cistern beneath the house, which also supplied the showers, a swimming pool and two hot tubs. A solar water heater heated the water without any temperature control. The owner said the water had no routine chlorination or filtration during the stay.
What testing found
At the territory’s request, CDC’s Legionella program sampled the property on February 3. Of twenty-five water, swab and filter samples, 11 (44%) grew Legionella pneumophila of other serogroups — in a hot tub filter, every shower, both bathroom sinks sampled, the cistern and the solar water heater. Serogroup 1, the only type the urine test detects, was not found.
No sample was taken from the patient’s lungs, which would have been needed to link a non-serogroup-1 infection directly to the house. But Legionella of any serogroup can infect people, and conditions that let one serogroup flourish suit the others. Finding the bacteria so widely, in samples taken on a single day, showed the house’s water was a good home for uncontrolled Legionella growth.
Fixing — and checking
The health department recommended disinfecting the plumbing and maintaining the water system with a multistage ultraviolet filter and routine chlorination, and the owner did the work on February 5–6. But when the department asked to retest in September, the owner declined — exposing a gap in its ability to confirm that fixes last.
Why it matters
Vacation rentals make up a growing share of the lodgings linked to travel-associated Legionnaires’ disease. In places with limited resources, such as the Virgin Islands, standard measures like controlled-temperature water heaters and multistage filtration are hard to put in place — and an estimated 90% of homes there rely on cisterns for drinking water. That raises the possibility of undetected cases among residents and travelers alike.
The lessons:
- Test for Legionella in patients with shortness of breath, cough and fatigue who have been to the Virgin Islands — even if they test positive for another respiratory virus, as this man did.
- When a case is found, inspect and sample the water system, carry out remediation, and retest promptly afterward.
The territory’s health department continues to work with CDC on surveillance, environmental sampling and outreach to vacation rental owners.
Sources
Based on Mac VV, Labgold K, Moline HL, et al., "Notes from the Field: Legionnaires Disease in a U.S. Traveler After Staying in a Private Vacation Rental House in the U.S. Virgin Islands — United States, February 2022," Morbidity and Mortality Weekly Report, Centers for Disease Control and Prevention; written with the U.S. Virgin Islands Department of Health and rewritten in hubnx’s own words.
Licence: CC0 1.0 (public domain) · Adapted from www.cdc.gov
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