Great! Just received a letter from ARIA sent to guests who stayed there between June 21 2011 to July 4th 2011 that their water tests detected elevated levels of Legionella bacteria in several of their guest rooms. In addition, the health officials have confirmed instances of Legionnaires’ disease in guests who visited ARIA. The letter goes on to state that they do regular testing, and that since this discovery they have “implemented additional precautionary measures”, that their most recent tests show no detectable level of active Legionella bacteria, and that they will continue to monitor their water quality on an ongoing basis.
Hmph. I half don’t believe them. What I think happened was several people got diagnosed with Legionnaires’ Disease. An outbreak investigation occurred which led health officials to ARIA as the source, confirmed when they tested their waters…rather than the other way around.
In either case I’m not surprised, and I’m not alarmed because as an infectious disease physician I understand the epidemiology and pathogenesis of Legionella infections. In fact last year I diagnosed a patient in my hospital with Legionnaire’s Disease. The patient was a nursing home resident so of course this led to the nursing home checking it’s waters and viola! there was the bacteria. They also implemented precautionary methods until tests indicated no further detectable levels of the bacteria. This diagnosis came during a time when I was trying to prevent the routine ordering of Legionella urinary antigen (the favoured diagnostic test) on everyone that came in with the sniffles, cough, or an infiltrate on chest x-ray because the truth is that it is not that common a cause of pneumonia. That’s akin to ordering a CT-scan for everyone who has bumped their head.
The Legionella bacteria was first discovered in 1976 during an outbreak at an American Legion convention, hence its name. It loves water and naturally occurs in lakes and streams. However artificial reservoirs like our piping system with its hot water and stagnation allow for proliferation and therefore outbreaks usually occur in large institutions such as hospitals, nursing homes, hotels, and cruise ships. For whatever reason, the risk of infection for someone living at home exposed to the bacteria is low. Infection is via inhalation or aspiration and depends on the degree of exposure, the burden of bacteria in the water reservoir, and the person’s immune status. There have been multiple other reservoirs and routes of infection described in the medical literature but to date there has been no report of person-to-person transmission.
Legionnaire’s disease is quite classic in its presentation, another reason testing for it in every patient with the sniffles shouldn’t be done. The infected person is usually quite sick with fever, diarrhea, headache or confusion, fatigue with actually unimpressive respiratory symptoms such as a nagging cough. On testing their heart rate is often slow, especially if they are elderly, and they have electrolyte abnormalities such as low sodium or blood in their urine.
There really isn’t much that one can do to prevent it and routine environmental cultures are actually not recommended. What is recommended is an increased index of suspicion on the part of the physician when someone presents with a constellation of symptoms that suggests Legionnaires, then environmental surveillance is done to find the source, and then source control at that point.
So what does ARIA’s letter mean to me, a guest who has likely been exposed to Legionella in the past few weeks? Nothing. Just that in the off-chance I come down with the above mentioned symptoms I better get myself to a doctor pronto!
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