Returning businesses warned of water-based disease
Building such as schools, leisure facilities, offices, gyms and salons that were forced to close for over two months due to the Covid 19 pandemic have been cautioned against Legionella growth, a disease found in water systems and associated equipment if they are not managed or used for a long period of time, according to the National Institute for Communicable Diseases (NICD).
“Legionnaires’ disease is a severe pneumonia caused by Legionella bacteria. The mortality rate ranges between 10 – 20% and symptoms may include a flu-like illness, followed by a dry cough, which progresses to a lower respiratory tract infection and pneumonia,” according to Sinenhlanhla Jimoh, Senior Communications Manager at NICD.
Legionella is not transmitted from person-to-person but a person becomes infected by breathing in water droplets containing the Legionella bacteria. Where water droplets can be created there is a risk of infection and this includes places like showers, taps and toilets, cooling towers and evaporative condensers of air conditioner, spa pools and Jacuzzis, ornamental fountains, humidifiers in food display cabinets and factories, dust suppression systems such as those used in construction, respiratory therapy equipment, spray irrigation systems and vehicle washes and pressure hoses.
This alert highlights the importance of maintaining water systems and performing maintenance of water systems prior to buildings being put back into use in order to minimise the risk of Legionnaires’ disease. Water systems that have been shut down, have had low water usage or limited control measures during the pandemic may result in an increased risk of Legionella bacteria being present.
To prevent the growth of Legionella and minimise the risk of Legionnaires’ disease on re-opening of buildings, hot water should be maintained above 60˚C and delivered to taps at temperatures above 50˚C. Cold water should be maintained below 20°C, if using a biocide, maintain target levels throughout the system. For premises that have had to shut down, perform controlled flushing of all hot and cold water outlets (showers, taps, toilets, urinals and any other points on the water system) at least weekly to prevent water stagnation.
Appropriate Personal Protective Equipment (PPE), such as an N95 respirator, should be used when performing flushing, cleaning or other aerosol-generating procedures. Buildings that have been closed for more than a month without maintenance should not be used straight away but water systems should be thoroughly flushed, cleaned and disinfected before bringing into use again. Some water systems, such as wet cooling systems, may require water testing prior to re-use.
“All persons can develop Legionnaire’s disease; however, the risk is higher in persons over the age of 50 years. Male gender, persons with immunodeficiency syndromes or chronic underlying medical conditions of the lung, heart or liver and smokers are also at increased risk,” said Jimoh.
The bacteria is found in low numbers in environmental water sources, including rivers, lakes, groundwater and moist soil.