Legionellosis is a lung infection caused by the Legionella Pneumophila bacterium. This disease does not seem to be part of our “list of diseases” perhaps because we do not often hear about it, however it is an infection that can even lead to death. So not only is it not to be underestimated, but it is not to be considered even a rarely contracted pathology.
Perhaps not everyone knows that in Italy, the Legionella risk assessment is a legal obligation. Law Decree 81 of 09 April 2008, the “Consolidated Safety Act”, provides operational indications to combat the phenomenon.
It dictates a global vision by establishing the obligation to “make safe” any aspect that may represent a risk to the health and safety of workers, passing through risk assessment and defining a strategy that must find its practical implementation.
“It is necessary to highlight by place or environment of work, whether or not there is a risk of exposure of workers to biological agents and what the technical, organizational, procedural measures implemented and must be implemented to avoid exposure by identifying and defining the necessary protective interventions ».
ELDSnet was also established, a body coordinated by the ECDC (European Center for Disease Prevention and Control), which has developed operational procedures implemented by the competent authorities following the reporting of legionella cases associated with travel. But let’s get to the practice. Legionella is a bacterium found in natural and artificial aquatic environments and spreads aerobically.
It can contaminate air conditioning systems, swimming pools and other water-based recreational systems (saunas, evaporative condensers, humidifiers, taps, diffusers, showers, toilets, fire prevention systems and water softeners). It is clear therefore that not only the air conditioning systems are involved as many think! Why are cases of legionellosis increasing on ships? The problem lies in the specific characteristics of the ships and their risk factors.
It is known, for example, that the quality of the supply water, especially in some countries is not the best. Furthermore, the water stored on board can be subjected to extreme temperatures during navigation in tropical regions. This is a factor that can be decisive for the proliferation of pathogenic microorganisms. Let’s briefly see what are the main risk factors.
Water temperature between 25 and 45 ° c (77 -113 ° f): Due to the extension of the pipes, it is difficult to maintain a high temperature in the water system in the ship. Water system design: ship’s water systems are complex and can be altered during refits.
Also there may be materials that are no longer approved or dead branches difficult to control. Stagnant water: the presence of large tanks and prolonged storage times can reduce the presence of residual chlorine in the water.
Accumulation of residues: limestone, corrosion, zinc, iron, manganese, rubber and silicone parts, algae and amoebas can sediment at the base of the kettles, constituting nutrients for legionella. Cleaning: Cleaning of pipes, taps and showers can be very difficult due to the limited access spaces. Materials: only materials approved for contact with drinking water and not suitable for microbial growth should be used. Complexity of the pipes: the water pipes for recreational facilities (e.g. whirlpools, swimming pools, etc.) are placed in confined spaces, this makes maintenance difficult. Knowledge: there are few experts available on board. Modification of water systems: emergency repairs can create blind branches. In risky environments such as yachts, adequate prevention to combat the multiplication and spread of Legionella through risk assessment and management is definitely a must.