Short essay proposal on Legionella Bacteria from a Cooling Tower

Introduce the hazard

Legionella bacteria is mainly found in fresh water systems and have the capacity to develop in the hot tubs, cooling towers of AC and other artificial water systems. Legionella has been detected in cooling towers of AC and it mainly spreads by breathing the contaminated air with aerosolized (hanging particles of bacteria in the air) and it typically does not spread directly between people as it is not a contagious disease. The risk factors of the disease indicate that old age people, smokers, people with chronic health conditions and individuals with immunosuppression are most likely to develop disease upon exposure to the bacterium [1]. The symptoms are mainly pneumonia like and affect respiratory system of individuals.

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Critical Analysis of hazard

While studying about the spread of legionella, it is found that only 0.1 to 5% of the individuals, exposed to the bacteria develop the disease, while others remain completely healthy. It is mentioned by researchers that even though all workers are not likely to develop legionnaire upon exposure, yet the contamination should not be overlooked and immediate actions should be taken to address the issue [2, 3]. Additionally, it is important to consider the varying risk factors of disease among different individuals developing the disease. When people, who develop the disease, have differentiated risk factors, then early consideration is needed by the management [4].

In terms of hazard assessment, both the employers as well as workers (more specifically maintenance workers) need to be aware of the conditions which are linked with enhanced growth of legionella [5]. The areas where bacterial growth is most likely, should be monitored periodically for detecting the early signs of bacterium presence. The most needed areas of assessment are;

  • Locations where water might stagnate and flow of water is not maintained
  • Water storage system
  • Hot water maintenance systems
  • Any side stream equipment, whereby regular flow is not maintained, such as by-pass lines
  • Any devices used for prevention of back flow

Moreover, there are some conditions which are more favorable than others, for the growth of legionella. For instance, it is notable that when temperatures are above 140°F, then there prevails lower risk regarding the development of disease [6]. Therefore, when water systems are not managed in effective way and temperature is low then the recommended, then there are enhanced chances of developing legionella [7].

Followed by the identification of maintenance issues, or diagnosis of any worker with the disease, the immediate action requires the employers to shut down the source of infection. For instance, in case of AC cooling tower, being the risk of infection, there is need to carry out maintenance of the underlying water system for decontaminating the cooling tower from legionella bacterium [8]. The legionella sampling and use of biofilms might be considered an appropriate way to detect the signs of bacteria followed by maintenance of the water system. Followed by this, the other action require the employers to extend communication with the employees who are at greater risk of exposure or who might have inhaled the bacterium through aerosolized air. By following these steps, legionnaire might be addressed in timely manner, restricting the further spread of disease [9, 10].

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Conclusion

Among other water maintenance systems, AC cooling towers are considered as key source for developing the legionella and inhaling of contaminated air might cause spread of disease. The hazards can be assessed to detect the early signs of legionella in vulnerable spots and management is needed to shut down the contaminated water systems on immediate basis to assure that spread of disease is controlled.

References

  1. Hyland JM, Hamlet N, Saunders C, Coppola J, Watt J. Outbreak of Legionnaires’ disease in West Fife: review of environmental guidelines needed. Public Health. 2008 Jan 1;122(1):79-83.
  2. Macher JM, Gold D, Cruz P, Kyle JL, Durrani TS, Shusterman D. Evaluation and management of exposure to infectious agents. Handbook of Occupational Safety and Health. 2019 Apr 10:147-97.
  3. Whiley H, Keegan A, Fallowfield H, Ross K. Uncertainties associated with assessing the public health risk from Legionella. Frontiers in microbiology. 2014 Sep 24;5:501.
  4. Oggioni C, Za A, Auxilia F, Faccini M, Senatore S, Vismara C, Foti M, Scaturro M, Fontana S, Rota MC, Crippa F. Legionnaires’ disease contracted from patient workplace: First report of a severe case of coinfection with varicella-zoster virus. American journal of infection control. 2016 Oct 1;44(10):1164-5.
  5. Crook B, Willerton L, Smith D, Wilson L, Poran V, Helps J, McDermott P. Legionella risk in evaporative cooling systems and underlying causes of associated breaches in health and safety compliance. International Journal of Hygiene and Environmental Health. 2020 Mar 1;224:113425.
  6. Kusnetsov J, Neuvonen LK, Korpio T, Uldum SA, Mentula S, Putus T, Minh NN, Martimo KP. Two Legionnaires’ disease cases associated with industrial waste water treatment plants: a case report. BMC Infectious diseases. 2010 Dec 1;10(1):343.
  7. Carson P, Mumford C. Legionnaires’ disease: causation, prevention and control. Loss Prevention Bulletin. 2010 Dec 1(216).
  8. Bohle P, Quinlan M. Managing occupational health and safety: A multidisciplinary approach. Macmillan Education AU; 2000.
  9. Su CP, de Perio MA, Cummings KJ, McCague AB, Luckhaupt SE, Sweeney MH. Case investigations of infectious diseases occurring in workplaces, United States, 2006–2015. Emerging infectious diseases. 2019 Mar;25(3):397
  10. Reinhart K. Legionnaires: How Safe Is the Water?. Professional Safety. 2019 Apr 1;64(04):26-30.