New York City health officials issued an alert today advising health care providers to consider Legionnaire’s disease when evaluating patients presenting with signs of pneumonia.
This comes after an increase in Legionnaire’s Disease was noted in the Bronx. In December 2014, 11 cases were diagnosed among Bronx residents compared with 2 in December 2013 and 3 in December 2012.
From January – December 2014, 61 total cases occurred in the Bronx, a rate of 4.3 compared to a citywide rate of 2.5 per 100,000 population. The Northeast Bronx was hit the hardest last year with 18 cases alone.
Legionnaires’ disease gained national notoriety in 1976 when the Centers for Disease Control and Prevention (CDC) discovered it during an epidemic of pneumonia among American legion members at a convention in Philadelphia.
The causative organism is the bacteria, Legionella pneumophila. Other species have also been implicated in Legionnaires’ disease. The legionella bacteria are found throughout nature, because of this most people become exposed to it but few develop symptoms.
The primary place in nature it’s found is water sources particularly at warmer temperatures; lakes, rivers and moist soil.
It is also found in man-made facilities (frequently the source of outbreaks) such as air-conditioning ducts and cooling towers, humidifiers, whirlpools and hospital equipment.
People get exposed through inhaling infectious aerosols from these water sources. There is no transmission from person to person.
The infection can appear in two clinical forms: Legionnaires’ disease and Pontiac fever.
Both conditions are typified by headache, fever, body aches and occasionally abdominal pain and diarrhea.
Legionnaires’ disease is the cause of pneumonia where a non-productive cough is typical. Fatality rates of this form of the infection are around 15 % even with improvements in treatment.
Pontiac fever is a self-limiting flu-like illness that does not progress to pneumonia or death. Diagnosis is usually made by typical symptoms in an outbreak setting.
Diagnosis of Legionnaires’ disease depends on identifying the bacteria in microbiological culture, detecting the antigen in urine samples or a fourfold increase in antibody titer.
Certain health conditions make you more susceptible to infection to include increasing age, smoking, chronic lung disease, malignancy and diabetes mellitus.
Legionnaires’ disease is treatable with antibiotics.
To following things can be done as preventive measures: cooling towers should be drained when not in use and cleaned to remove scale and sediment and biocides can be used to limit bacterial growth. Tap water should not be used in respiratory therapy devices.
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We experienced a CDC-investigated L. pneumophila outbreak here in Memphis, TN at Baptist Memorial Hospital in the late 1970’s where the bacterium was spewed out onto passersby around the hospital from the air conditioning system and infected people who never set foot in the building. It appears sporadically around the world and can be controlled when water in AC cooling towers are properly acidified.