Legionnaire’s Disease –

Challenges and Solutions

Molly McKain - May 9, 2016

The Cost of Legionella 


The true cost of legionella is not paid by the facility in which the outbreak takes place, but by the infected patients and their families. A hospital or a nursing home could spend hundreds of thousands of dollars on cleaning the contaminated water system and containing a public relations nightmare, but the far greater price is paid by the patient who loses their life. When a legionella outbreak occurs, a facility responds with an intense water distribution system disinfection. The disinfection requires dangerously high doses of chlorine to be added to the water at the Point-of-Entry (POE) and pumped through the entire system. The chlorinated water must then be flushed down the drain. During this process, an unavoidable disruption of service will take place and bottled water will need to be brought into the facility.


The chance of dying from hospital-acquired legionellosis in 30 days is 33.3% - more than twice that of community-acquired legionellosis, 12.9%, per the Special Pathogens Laboratory in Pittsburgh, PA, USA. The elderly and immunocompromised are most likely to be hospital patients and are significantly more susceptible to disease. A normal, healthy human body may successfully fight off the legionella pathogen, but a compromised one cannot.


The number of legionnaire’s disease cases varies from year to year, but on average there are 18,000 reported cases in the United States, per the Center for Disease Control (CDC), and 6,000 in the European Center for Disease Prevention and Control (ECDC) member countries. Assuming half of those patients were diagnosed with hospital-acquired legionellosis and half were diagnosed with community-acquired legionellosis, over 5,000 people would lose their lives. More troubling is knowing the number of cases is low due to unreported cases and issues with diagnostic testing.

Legionella bacteria treated with UV LEDs

The trouble with diagnosing


Multiple types of legionella pathogens cause legionnaire’s disease, but most diagnostic tests only scan for some of them. Legionella pneumophilia serogroup 1 is the most common cause of legionnaire’s disease, but it can quickly and easily be identified via the urine antigen test.  


According to Victor Yu, MD, a researcher with the Special Pathogen Laboratory, legionella pneumophilia serogroups 2-14 are also found in hospitals. In a 2009 Italian study, researchers tested water in 129 hospitals and found serogroups 2-14 in 55% of the hospitals – proving testing for all serogroups is required. A culture of sputum is the only way to test for serogroups 2-14, but cultures are not widely available and rarely done.


Legionnaire’s disease can also go undetected once a patient is diagnosed with pneumonia. Legionella may have caused the pneumonia, but a legionella test was never administered. The Special Pathogen Laboratory estimates 20% of all hospital-acquired legionnaire’s disease patients have no abnormalities on chest x-rays when symptoms begin. Best practice dictates all hospital-acquired pneumonia patients should be tested for legionella in hopes of facilities detecting, and preventing, a possible outbreak. 


Prevention by disinfection


Reacting to legionella can be costly, time-consuming, and stressful for all parties involved. Avoiding legionella via preventative maintenance is significantly cheaper and easier than treating it. The most effective way to inhibit legionella is to prevent the formation of biofilm.


Chemical disinfection 


The most common hospital water system disinfection techniques are chlorine and copper-silver ionization.  The chlorination method disinfects water by using chlorine to dissolve organic material in the water. A chlorine system is difficult to monitor because the concentration of chlorine required for disinfection changes with environmental conditions. Disinfected water will still contain byproducts that will adversely change the taste of the water. None of the excess chlorine or byproducts are removed so they are consumed by hospital patients, staff members, and their families, potentially causing long-term health issues. 


Copper-silver ionization has been promoted as the ‘latest and greatest’ legionella preventing technology, but it has yet to be recognized by the Center for Disease Control (CDC). Ionization treatments add charged copper ions and silver ions to water to prevent the formation of biofilm. Without proper monitoring, ionization systems can lead to copper poisoning and silver poisoning. The risk of poisoning is so great that some experts recommend a government registration program to ensure proper monitoring of the systems. These systems cost roughly $40,000 to purchase, and cost another $15,000 in annual ion replenishment expenses. 


Physical disinfection 


An alternative to chemical disinfection is physical disinfection. Physical disinfection is not dependent on chemical reactions, but utilizes filtration and/or ultraviolet (UV) light to clean the water. Microfilters are capable of removing organic material from the water, but they clog quickly and need replacing often. 


UV systems disinfect water by inactivating pathogens in the water. Traditional, mercury-based UV systems require large, tube-shaped reactors and use a lot of electricity. Most of a mercury lamp’s energy is lost as heat, not light, so the temperature of the water being disinfected may increase. 


Mercury-based UV systems have usage limitations. Mercury lamps decay with each on/off cycle so only a limited number of cycles are permitted before replacement is necessary. These lamps also require 10 to 20 minutes of warmup time before they are able to disinfect and a breakage during use would release mercury into the drinking water. Limitations of traditional UV systems cause them to be applied to POE applications only and if the water distribution system has not been properly maintained, the water will most likely be re-contaminated before reaching hospital patients. 


New UV-C Light Emitting Diode (LED) systems allow UV disinfection to be used in Point-of-Use (POU) applications. UV-C LEDs have been combined with a compact reactor to result in a UV system that does not require a warmup time and can endure infinite on/off cycles. This new technology is easy to use, requires little electricity, and can be incorporated into any POU system. There is no need for a large POE disinfection system when the water can be disinfected milliseconds before it reaches patients. There are only a few UV-C LED disinfection units commercially available now, but this technology is expected to replace all mercury-based systems in the future. 

"UV-C LEDs open up UV applications never before possible with traditional, mercury-based UV systems."


There are two main components to proactively combating Legionnaire’s disease. First, change hospital policy to include testing for serogroups 1-14 of legionella, not just serogroup 1. This requires cultures of sputum to be widely used and readily available. All patients who contract hospital-acquired pneumonia should also be tested for legionella to help identify and control a potential outbreak. 

Second, a proper water disinfection system needs to be in place. The system must be regularly maintained and tested to ensure the system is functioning properly and preventing legionella growth. A UV-C LED system effectively eliminates all pathogens in the water without changing the taste of the water or introducing harmful chemicals to the human body.

Avoiding a Legionnaire’s disease outbreak means avoiding the stress and monetary burden of purging the water system and loss of future income that accompanies it. The combination of a water disinfection system and better legionella testing will prevail in the fight against legionella. Hospital patients no longer need to fear Legionnaire’s disease because they cannot acquire an illness that has already been eliminated.