Legionella is a form of Gram-negative bacteria with species such as Legionella pneumophila. It can be identified through a cultured or silver stain. It exists in a wide range of environment including aquatic and soil system. It has more than 50 species. Nonetheless, it is not spread from person to person the side chains in the cell wall possess chemical compounds which accounts for the infection1. After entering the lungs, it contaminates the alveolar macrophages where the replication stakes places. Consequently, it can lead to a less serious infection known as Pontiac fever or serious illness referred to as Legionnaire disease.2
Legionella pneumophila is the bacteria species that is responsible for serious illnesses such as Pontiac fever and Legionnaires’ disease. The infection is characterized by lethal, often severe, type of pneumonia. After a victim inhales the contaminated air, the bacteria grow in the in the lungs. After nearly 10 days, a person starts to manifest serious symptoms such as high fever and coughing1. Additionally, the lungs begin to suffer from sign and symptoms similar to those of pneumonia. The bacteria usually exist in both non-potable and potable water structures. The Australia National Notifiable Diseases Surveillance System (NNDSS) in 2014 reported 424 cases of Legionnaire disease. The cases denoted a proportion of 1.8 per 100, 000 persons. Fortunately, as compared to the previous year, the number of diseases decreased by approximately 17 percent. Moreover, L. pneumophila accounted for 54 percent of the disease in the country. The bacterial infection contributed to 78 percent of the mortality rate. Annually, nearly 115 to 229 persons suffer from the disease in Australia3. The distribution of the disease indicates that the rate of infections varied across the country. Western Australia recorded the highest rate of infection at 4.5 per 100,000 people while the Australian Capital Territory registered 0.5 per 100,000 people. The new cases of the disease were higher among males (65 percent) as compared to females (35 percent)4.
Moreover, a large proportion of these patients are taken to the intensive care unit (ICU) due to associated complications. Furthermore, a significant number of patients will experience long-run impairment, which affects the quality of life5. The victims exhibit a wide range of health effects. A study by WHO revealed that 75 percent of survivors demonstrated prolonged fatigue, while 63 percent and 66 percent of the patients indicated neuromuscular symptoms and neurologic symptoms6.
Legionnaire presents a serious public health concern in the world. The outbreak of the disease can lead to loss of many lives. A study has highlighted that the disease accounts for 2-13 percent of incidences of pneumonia acquired in the community needing hospitalization. The transmission of Legionella has been linked largely with the inhalation of water droplets having the microorganism7.
Various environmental factors have been linked with the outbreaks of legionella especially water distribution structure in ships, hotels and homes, ornamental fountains, and whirlpool spas 2. More importantly, cooling towers have been implicated with high colonization levels of the Legionella bacteria. Similarly, the evaporative condensers are largely colonized hence provide a perfect environment for consequent generation of aerosol8. Cooling towers have been identified as the main cause of community epidemics of Legionella infection. The bacteria develop quickly at an optimum temperature of between 35oC and 40oC but at 60oC, the temperatures destroy the bacteria. The cooling towers facilitate aerosolization and amplification of the bacteria8. Noteworthy, amplification occurs when the bacteria are permitted to multiply unrestricted in a wet and warm environment. The water contains nutrients, which act as source of food for the bacteria coupled by favorable environment. Similarly, the absence of UV light in the living room encourages it to grow faster. The UV light destroys bacteria. Nonetheless, the study delivered a weak causal association between the epidemics and cooling towers. Subsequently, the significance of cooling towers as the key basis of infection has been probed5. Challenges exist in investigations of an epidemic due to the repeated delay in reporting a new case and the problems of detecting possible sources.
All persons inhaling the water droplets having the bacteria are at risk of the infection. Moreover, males are more susceptible to the disease as compared to females. Similarly, persons aged more than 45 years coupled with impaired immune system or smokers are largely vulnerable8. A young person appears to be less vulnerable to Legionnaire disease.
Due to rising number of cases and emerging epidemics in the United States, various states and local governments have enacted legislation aiming to regulate the maintenance of cooling towers in the country. In addition, the laws are intended to ensure that water systems that are accessed by the public are free from Legionella bacteria1. Moreover, the property owners, developers of residential real estates, managers, and investors of healthcare, hospitality, and commercial centers are held liable for the risk of the bacteria. In this regard, they are expected to initiate a plan that ensures they remain proactive in the prevention of Legionella10. Furthermore, the statute expects managers of such buildings to ensure that the potable water systems utilized for showering, cooling systems, decorative fountains, and