HEALTHWATCH
Problem in water drops
DR. HIRAMALINI SESHADRI
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The bug that causes Legionnaires' disease lives inside amoebae in warm fresh water.
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The bug that causes Legionnaires' disease lives inside amoebae in warm fresh water.
WHEN 73-year-old Mariyamma from the suburbs around Chennai landed up in the Emergency with diarrhoea, vomiting, fever and delirium, the last thing on my mind was Legionnaires' disease.
Now what's that? Well, even doctors see it but rarely. The first case in India was reported in 1977 and senior chest physician, Dr. Narasimhan, says he saw just around four cases last year. So it is uncommon. But is that because we aren't looking hard enough?
My first brush with Legionnaires was through Laurel and Hardy. They immortalised the American Legion meets at Philadelphia through their evergreen comedies. Incidentally, it was at one such meet that 204 elderly men went down with Acute Respiratory Failure.
Attacking the lungs
When 34 succumbed to this weird illness "Legionnaires' disease" was born. The bug was found to be a rod-like organism that did not take up the standard laboratory Gram stain; hence it was called "gram negative". It mainly attacked the victims' lungs and hence was christened Legionella pneumophila.
Today we know that there are over 48 species of Legionella and over 70 strains of it. It is a classic example of the camel and Arab story with Legionella being the camel. The bug lives inside amoebae in warm fresh water — in ponds, lakes, more so in cooling towers, AC systems and even tap water.
When a vulnerable host breathes in the tiny droplet with even one amoeba hosting the bug, the drama begins. Vulnerable translates as elderly, smoker, alcoholic, diabetic, immunesuppressed... as usual males are at higher risk. The bug comes out in the lungs. The foot soldiers of the body, the white cells, then surround it and virtually coil around it.
The clever bug allows itself to be engulfed by the white cell. Once inside, it shows its true colours. The white cells' antibacterial missile systems don't seem to touch the bug; on the contrary, it puts out powerful enzymes that kill the white cell and damages the surrounding lung as well!
Spread
Legionella infection is one of the more serious pneumonias. The mortality rate in hospitals is five to 35 percent. Aerosolisation from contaminated water sources is the source of infection. Person to person infection does not occur. The disease manifests after two days or two weeks. A mild form, which goes by the fashionable name of Pontiac fever, is a flu-like illness that goes away on its own in five to seven days.
Unless the doctor looks out and tests for Legionella, these cases are invariably missed and put down as just "flu" or "viral fever". The more serious illness usually presents with history of high fever and chills. Cough is usually dry but associated with breathlessness.
Variants
There is a gut variant of the disease too where, like Mariyamma, the patient presents with diarrhoea and vomiting and sends physicians barking up the wrong tree trying to make a diagnosis. Both types can be associated with delirium, headache and mental confusion because of which even the possibility of meningitis crosses the doctor's mind. Fortunately the bug responds to most of the newer higher antibiotics though the drug of choice is erythromycin or azithromycin.
The secret to success is starting appropriate antibiotics right away and using oxygen and even artificial ventilation if needed, besides excellent supportive therapy, till things are under control.
How does one diagnose the disease? A simple urine test, which is very specific, detects the bacterium's antigen; there is a blood test as well. Is there any preventive? There is no vaccine.
But as part of occupational safety measures, cooling towers, AC systems, spas, cruise ships are expected to take steps to keep Legionella colony counts below certain levels. UV light irradiation and boiling kill the bug.
In the meantime, Mariyamma has conquered Legionnaires' disease and is on the way home.
But this is where the difference between India and the West shows. Recently in the U.K. an entire courthouse was closed down when one employee was diagnosed with Legionnaires' disease. The entire water system, AC plants and so on are being tested.
In France, community health officials traced the source of infection to an industrial cooling tower six kilometres away from the village where Legionnaires' disease occurred.
In India, our community health department first needs to attend to mosquito control, safe drinking water and sanitation.
The writer is a Senior Consultant, Holistic Internal Medicine and Rheumatology Chennai. E-mail: hiramalini@yahoo.com
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