Legionella and Legionnaires disease - dangers and control methods

15 June, 2012
Pat Perry

As authorities in Edinburgh scramble to locate the source of the Legionnaires' disease outbreak that has claimed the life of two people and infected a further 40 people, it's a stark warning to all about the dangers of an outbreak.

Legionella pneumophila is a bacterium widely found in nature and is only one of at least 23 different species of legionella. Over half of these have caused illness in humans, but Legionella requires precise growth conditions, which of course need to be prevented, especially where there's a risk of human contact.

So, how did this outbreak occur and what could have been done to prevent it? Samantha Maxwell from health and safety experts, Perry Scott Nash explains: "The bacteria is common and can be found naturally, usually in low numbers, in water sources such as rivers and reservoirs. If the bacteria get into the water systems used in premises then they may cause a risk to humans if people are exposed to them through air conditioning systems, air-cooling systems or, water systems used for baths and showers and swimming pools and spas. People become infected when they inhale air that contains tiny droplets of water called aerosols that contain the Legionella bacteria. If the bacteria get inhaled into the lungs they can cause infection. But to quash a myth, the disease cannot be acquired from drinking water that contains the bacteria nor can it be passed from person to person". Adding: "The most high-risk areas where people are at risk include:

  • Showers and baths
  • Spa baths and whirlpool baths
  • Turkish baths and saunas
  • Cooling towers and evaporative condensers even if situated on the roof or in the grounds
  • Ornamental fountains, particularly indoors
  • Humidified food displays

The risk of legionnaires' disease can be avoided. Any premises that does not have an active programme to control the growth of legionella is negligent in ensuring the safety of their guests/customers. This programme should include the following:

  • Have one named person responsible for legionella control.
  • Ensure the named person is trained in control of legionella and other staff are trained to be aware of the importance of their role in controlling legionella.
  • Keep hot water hot and circulating at all times: 50ºC - 60ºC (too hot to put hands into or under for more than a few seconds).
  • Keep cold water cold at all times. It should be maintained at temperatures below 25ºC.
  • Run all taps and showers in guestrooms (where present) for several minutes at least once a week if they are unoccupied and always prior to occupation.
  • Keep shower heads and taps clean and free from scale.
  • Clean and disinfect cooling towers and associated pipes used in air conditioning systems regularly - at least twice a year.
  • Clean and disinfect water heaters (calorifiers) once a year.

This latest outbreak is a stark reminder of the dangers of this type of bacteria and reinforces the importance of correct procedures in areas associated with risk. Those responsible for public and employee safety must have in place strict controls, including water temperature management, water system cleaning regimes, record keeping, as well as staff training to avoid potential issues with Legionella. For more information, Contact Us

 

As authorities in Edinburgh scramble to locate the source of the Legionnaires' disease outbreak that has claimed the life of two people and infected a further 40 people, it's a stark warning to all about the dangers of an outbreak.

Legionella pneumophila is a bacterium widely found in nature and is only one of at least 23 different species of legionella. Over half of these have caused illness in humans, but Legionella requires precise growth conditions, which of course need to be prevented, especially where there's a risk of human contact.

So, how did this outbreak occur and what could have been done to prevent it? Samantha Maxwell from health and safety experts, Perry Scott Nash explains: "The bacteria is common and can be found naturally, usually in low numbers, in water sources such as rivers and reservoirs. If the bacteria get into the water systems used in premises then they may cause a risk to humans if people are exposed to them through air conditioning systems, air-cooling systems or, water systems used for baths and showers and swimming pools and spas. People become infected when they inhale air that contains tiny droplets of water called aerosols that contain the Legionella bacteria. If the bacteria get inhaled into the lungs they can cause infection. But to quash a myth, the disease cannot be acquired from drinking water that contains the bacteria nor can it be passed from person to person". Adding: "The most high-risk areas where people are at risk include:

  • Showers and baths
  • Spa baths and whirlpool baths
  • Turkish baths and saunas
  • Cooling towers and evaporative condensers even if situated on the roof or in the grounds
  • Ornamental fountains, particularly indoors
  • Humidified food displays

The risk of legionnaires' disease can be avoided. Any premises that does not have an active programme to control the growth of legionella is negligent in ensuring the safety of their guests/customers. This programme should include the following:

  • Have one named person responsible for legionella control.
  • Ensure the named person is trained in control of legionella and other staff are trained to be aware of the importance of their role in controlling legionella.
  • Keep hot water hot and circulating at all times: 50ºC - 60ºC (too hot to put hands into or under for more than a few seconds).
  • Keep cold water cold at all times. It should be maintained at temperatures below 25ºC.
  • Run all taps and showers in guestrooms (where present) for several minutes at least once a week if they are unoccupied and always prior to occupation.
  • Keep shower heads and taps clean and free from scale.
  • Clean and disinfect cooling towers and associated pipes used in air conditioning systems regularly - at least twice a year.
  • Clean and disinfect water heaters (calorifiers) once a year.

This latest outbreak is a stark reminder of the dangers of this type of bacteria and reinforces the importance of correct procedures in areas associated with risk. Those responsible for public and employee safety must have in place strict controls, including water temperature management, water system cleaning regimes, record keeping, as well as staff training to avoid potential issues with Legionella.

For more information, Contact Us

 

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