Legionella Sampling
A Practical Guide On Legionella
Legionella is a ubiquitous organism found in virtually all surface water sources. The organism is classified in a number of sero groups. Some of the sero groups are much more virulent than others. When a heavily contaminated water source is atomized and then deeply inhaled, it can cause a severe form of pneumonia. People with impaired lung function or impaired immune function are much more susceptible than others. In any event, approximately 18,000 people are reported to contract this form of Pneumonia each year in the United States. Based on published reports, up to 30% of those who contract the disease succumb to it.
The CDC combines Influenza and Pneumonia as a single cause of death. The reason for this is that you do not have to get the Flu to get Pneumonia but it is the Pneumonia that will ultimately kill you.
Influenza/pneumonia is currently the 8th leading cause of the death in the United States. The Spanish Flu of 1918 wiped out roughly 5% of the entire population of the planet.
To put this stuff in perspective, the odds of survival after contracting Legionella are statistically lower than those who contracted the Spanish Flu. The only thing worse in recorded history along these lines would be the Bird Flu which currently has a mortality rate of around 50% or more.
The bad news is that Legionella is a pretty mean bug but the good news is it is fairly easily controlled.
There are a number of guidelines that have been published on the prevention and control of Legionella. Some of these are as follows:
- OSHA
- ASHRAE
- Cooling Tower Institute
To condense the Guidelines into a nut shell, you need a good biocide program or high temperature to keep the Legionella organism in check. Eliminating the organism altogether may be desirable but not always possible or even feasible. You do however need a plan. Putting your head in the sand and ignoring the threat is not a good idea. This is how you get in trouble.
In order to stay out of trouble, we recommend that you implement a four point formalized program as follows:
Legionella Risk Assessment Program:
All organizations should implement a Risk Assessment Program. This means you should complete an audit of all systems where Legionella has a chance of infecting a system and identifying the risk of someone contracting Legionella through exposure to that system.
Legionella Guideline Compliance Review:
After completion of the Legionella Risk Assessment Audit, you should review all procedures related to those systems to see if they are in compliance with the generally accepted Guidelines for the prevention or minimization of Legionella.
Legionella Auditing Program:
After you have reviewed the risks and guideline compliance, it is time to look and see just how well this stuff is working. The systems should be sampled and tested for both count and sero group. This needs to be done periodically and the testing should be conducted by a laboratory well versed in this type of analysis. Field testing for Legionella is not a very good idea unless it is backed up by Lab analysis.
Legionella Reaction Protocol:
Before you test a system for Legionella you should have a Reaction Protocol prepared. A Reaction Protocol means “what are we going to do when we find it?”
The following is a partial list of common types of waters that can become infected with Legionella:
- Cooling Towers
- Decorative Fountains
- Spray Misters
- Humidification Systems
- Domestic Hot Water
- Domestic Cold Water
- Swimming Pools
- Spas