As the hospitality sector is ready to reopen its doors and welcome back customers, some public health risks may arise if water systems in hotels have not been properly managed during the lockdown, a health expert warned.
With temperatures rising, water distribution systems are at risk of being colonised by pathogens such as the Legionella bacteria.
Cultures of this Pneumonia-causing bacteria can proliferate in warmer parts of water systems and cooling towers and then spread through the mist emitted by air-conditioning units in large buildings.
Most outbreaks and cases of Legionnaires disease happen during the summer season, explained Susanne Lee, a microbiologist with many years of experience in UK public health agencies and currently director of an independent consultancy Legionella Ltd.
According to the expert, this risk increases if the main means of controlling Legionella growth within water systems have not been put in place during the closures of the hotelier industry.
“At the beginning of the COVID pandemic, we produced some guidelines to help people to close down buildings safely, particularly in the accommodation sector,” she said.
Public health agencies gave a range of options for the proper maintenance of the water systems that could help to avoid the costly chemical treatment with biocide in case contaminated water is detected.
The ideal maintenance in water systems is to keep the temperature for cold water below 20 degrees – or 25 if it is not practical for buildings to achieve it – and above 50 degrees for hot water – which means that within one minute of turning on the tap, you should be able to achieve 50 degrees at least, and ideally 55.
The extension of the Legionella bacteria monitoring to every potable water system in the EU is part of the new risk assessment analysis included in the revised EU’s Drinking Water Directive (DWD).
There are 62 species of this bacteria known to date but Legionella pneumophila serogroup 1, causes most Legionnaires disease infections and the deadly form of pneumonia. In 2018, Legionella pneumophila amounted to approximately 94.1% of confirmed cases in Europe.
In Annex III of the drinking water directive, EU countries will be provided with the option of using alternative Legionella pneumophila testing to achieve public health protection objectives and are also called upon to establish guidelines for sampling methods of legionella.
How (not) to contract Legionellosis
Basically, all buildings that use or store water needed their water systems to be managed well during the pandemic, according to the expert. Any equipment that contains water, such as spa pools and hot tubs, is also included.
“[To have contamination,] you need a system that has water in it and you need to have the Legionella to be disseminated into the environment,” she said.
The most common way for people to be infected is by inhaling very fine aerosols which have been derived from contaminated water sources.
“So whether it’s having a shower, just turning on a tap, or flushing toilets, the force of the water hitting the base creates an aerosol,” the expert explained.
However, hot and cold water systems are the second most common source of infection, since in the past there have been some large outbreaks caused by evaporative cooling towers such as the ones for comfort cooling in hotels.
Exposure can be for quite a short time too. “We know, for example, that when we had an outbreak in London from a cooling tower on the BBC roof, somebody who was sitting on an open-air bus contracted Legionnaires disease just passing through Piccadilly,” Lee said.
Much depends on how vulnerable people are to infections, as those with underlying conditions – smokers, immunocompromised persons or diabetics, for instance – are more likely to get Legionnaires disease.
Tests are needed.
In non-COVID times, about half of Legionellosis cases in the UK are travel-related, the expert told EURACTIV.
“Before opening up, hotels need to do a risk assessment with somebody who will go and check water storage, tanks and do some tests on those to see that the system hasn’t been subject to colonisation if they’ve kept it running,” she added.
However, laboratory capacity to do testing have become recently problematic as they are not able to cope with the same intensity of sampling.
“Some labs have gone into a 24-hour working mode so they can increase the number of samples they can get through by working on a shift basis”, she said, adding that it is still an additional challenge to find someone who will be able to process samples in a timely manner.
Another thing that makes the Legionella detection a tough task is that it is not just about the water coming out of the tap.
“I do have some concerns on whether some of these apartments on accommodation websites with a hot tub on the balcony have been managed appropriately during closures because it’s quite difficult to manage those types of equipment even in the best of times,” she concluded.
[Edited by Zoran Radosavljevic]