MOBILE, Ala. — The Mobile County Health Department has reported the third confirmed case of Legionnaires’ disease this year in a Mobile County resident, this one in a person who recently returned from international travel.
The individual is receiving appropriate medical attention. Based on available information, the illness appears to be travel-associated.
The health department is working with the Alabama Department of Public Health and relevant partners on a routine public health investigation, including a review of potential exposures during the 14 days before symptoms began.
Not an Outbreak
The health department was explicit on this point: a single travel-associated case does not indicate a local outbreak.
The CDC defines a Legionnaires’ disease outbreak as two or more cases connected to the same possible source during a 12-month period. Three unconnected cases over the course of a year in a county of Mobile’s size is a different situation entirely from a cluster traced to one building.
The 14-day exposure review is why that distinction can be drawn with confidence. Because Legionella grows in specific water systems rather than spreading between people, investigators can work backward through a patient’s movements during the incubation window and identify where exposure plausibly occurred — a hotel, a cruise ship, a building’s plumbing.
What Legionnaires’ Disease Is
Legionnaires’ disease is a serious type of pneumonia caused by Legionella bacteria. People become ill after breathing in small droplets or mist containing the bacteria.
Legionella grows in certain human-made water systems, particularly where warm water and complex plumbing are present. Common sources include:
- Showers
- Hot-water tanks
- Decorative fountains
- Hot tubs
- Cooling towers
- Hotels, cruise ships, hospitals and other large buildings
It is not generally spread from person to person.
That last point matters for how the public should understand a reported case. A person with Legionnaires’ disease is not contagious to family members or coworkers. The risk lies in a water system, not in a patient.
The Symptoms
Symptoms can include fever, cough, shortness of breath, headache, muscle aches, fatigue and pneumonia. They commonly begin two to 14 days after exposure.
Because those symptoms resemble other forms of pneumonia, laboratory testing is required to determine whether a person has Legionnaires’ disease specifically.
That diagnostic step is the practical reason the travel history matters. Legionella is not detected on the tests ordinarily run for community-acquired pneumonia; it requires specific testing, and a clinician orders that testing when something in the history — recent travel, a hotel stay, a cruise — raises the possibility.
What the Health Officer Said
“Awareness and early medical care are important because Legionnaires’ disease can become serious, particularly for people at greater risk,” said Mobile County Health Officer Dr. Kevin Michaels. “Anyone who develops pneumonia-like symptoms after travel, a hotel stay, a cruise, or another possible exposure to aerosolized water should contact a health care provider promptly and share their recent travel history.”
The instruction to share travel history is the actionable part of that statement. A patient who mentions a recent cruise gives a clinician a reason to order testing that would not otherwise be ordered.
Who Is at Higher Risk
Most healthy people exposed to Legionella do not become ill. Risk concentrates in specific groups:
- Adults age 50 and older
- Current or former smokers
- People with chronic lung disease
- People with weakened immune systems
Individuals in those groups should seek care quickly if they develop symptoms.
Prevention Is a Building Management Problem
The health department’s prevention guidance is directed less at individuals than at the people who operate buildings.
The best prevention is proper maintenance and management of building water systems. Owners and managers of hotels, health care facilities, long-term care facilities, large residential buildings and other properties with complex water systems should maintain water-management practices designed to limit Legionella growth and spread.
The CDC identifies water-system maintenance as the key measure for preventing Legionnaires’ disease.
The underlying reason is that Legionella thrives under conditions a poorly managed building creates: water held at warm but not hot temperatures, stagnation in infrequently used sections of plumbing, biofilm accumulation, and inadequate disinfectant residual. A water management program addresses those conditions systematically — monitoring temperatures, flushing low-use outlets, maintaining disinfectant levels and servicing cooling towers.
Buildings with extended periods of low occupancy face elevated risk, because water sits in pipes rather than moving through them.
Information Without Alarm
The Mobile County Health Department encouraged residents to remain informed without alarm.
That framing is appropriate. Travel-associated Legionnaires’ cases are reported regularly across the country, and public health agencies investigate each one specifically to determine whether it connects to anything local. Reporting a single case publicly is how a health department demonstrates it is doing that work.
Questions
Residents with questions about Legionnaires’ disease may contact the Mobile County Health Department’s Infectious Diseases & Outbreaks team at 251-690-8970.