and prevention legionella

What is Legionella?

Legionella is a disease caused by a bacterium that spreads through the airways. This disease, known as legionellosis, mainly attacks the respiratory tract and its system, in some cases even in the form of lung inflammation, and can be very serious.

To fully understand the danger level of Legionella, it is necessary to learn some basic concepts.

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Gram-negative bacteria are those that remain pink-colored after undergoing Gram staining. They are contrasted with Gram-positive bacteria, which remain blue-violet at the beginning of the Gram procedure. This distinction is useful for classifying bacteria based on their lesser or greater resistance to antibiotics.
Legionella is a bacterium, defined as gram-negative, meaning it stays pink following the Gram test. This bacterium can live in water and sludge. It can also be transmitted through air conditioning systems by air dispersion. The bacterium can develop into two different pathologies:

  • the so-called “Legionnaires’ disease” – a more severe epidemic
  • “Pontiac fever” – a milder infection

There is also a further possibility, identified as asymptomatic, which is characterized by the presence of antibodies.
The contagious pathology that manifests as pneumonia, also known as legionellosis has a mortality rate of about 15%. In its flu-like form, in the variant of Pontiac fever fever, it has a not too demanding course.

Why does it develop?

The ideal environment for Legionella to develop and proliferate is water. The Legionella bacterium develops wherever there are conditions for it to survive, mainly where there is water stagnation, such as in a natural or artificial water basin.

The transition from the natural environment to the artificial environment of the Legionella bacterium occurs through water pipes.

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Indeed, it is through the capillary distributed potable water network that it manages to ascend and settle inside the buildings’ systems, in systems to humidify and air condition environments, in swimming pools, and inside decorative fountains in cities.
The ideal climatic condition for the development and growth of the Legionella bacterium is at an average temperature ranging from 35 to 37 degrees Celsius. There are also two other states of the bacterium’s life: below 25 degrees Celsius, it is considered dormant if it exists, and towards 45 degrees Celsius, it stops reproducing. Moreover, they are so aggressive as bacteria that they manage to live in environments with a pH value ranging from 5.5 to 8, considering the neutral pH value as 7.
Moreover, the Legionella bacterium develops and multiplies in all those conditions of scaling and lime deposit, of wear present in water systems. The same systems that, by characteristics and typology, present elements of junction, dead points, and accumulation points where the possibility of water stagnation is very high. These are the ideal conditions for the Legionella bacterium to find fertile ground to proliferate undisturbed.
Generally, this type of bacterium from the Legionella family does not live alone in stagnant waters. Indeed, it has been ascertained that environments populated by protozoa such as amoebas and ciliates, walls covered with green algae, and bacterial biofilm, the Legionella bacterium can live as a parasite. Through the elements present, it protects itself and spreads from external aggression. Indeed, protozoa provide both the nutrient substance and defense against the unfavorable conditions of the environment in which it lives, such as high temperature or other decontaminating elements.

what are the health risks

What are the risks if we are infected with Legionella? Usually, the disease known as Legionellosis presents symptoms such as: fever, with or without chills, dry or productive cough.

Like many febrile aspects, it can manifest with muscle pains, migraine, fatigue, loss of appetite, and rarely diarrhea.

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By performing more accurate checks, through more targeted analyses in specialized centers, you could find renal dysfunctions and evident signs of lung inflammations.
Normally, the incubation of Legionellosis ranges from 3 to 9/10 days.

It is evident that to distinguish between various types of lung inflammation and be sure that it is Legionella, it is necessary to perform specific clinical exams The simplest thing, from a diagnostic point of view, if there is doubt about the presence of the Legionella bacterium is:

  • identify the bacterium in saliva
  • the presence of urine antigens
  • the value of antibodies present in the venous sample

In case of mild fever, which may manifest almost immediately once in contact with the bacterium, legionellosis could last a few days causing mild muscle soreness, but certainly not pneumonia.

It is important to limit and confine the proliferation of Legionella bacteria in all those environments that are considered risky: such as RSA structures and hospitals but also in shopping centers. The bacterium does not discriminate by age, anyone can be infected, mainly people with critical lung situations.

Legionellosis can infect people of all ages, but it is particularly prevalent in the elderly, among individuals who smoke or who have certain chronic lung disease conditions.

What to do in case
of Legionella infection?

Legionella infection can present itself, as already mentioned above, in two distinct ways:

  • as the disease commonly known as legionnaires’, which in most cases presents acute and violent forms of lung inflammation;
  • as a temperature rise known as Pontiac fever, which is usually less incisive and severe than the former.
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Since it is a bacterial pathology, to combat legionellosis, we are forced to use treatments with antibiotic medicines. Obviously, it is the attending physician who prescribes the most appropriate medications. The second case, that of Pontiac, is the benign variant, which does not impose any emergency treatment. Conversely, where the variant of legionella presents itself in its most violent form: from pneumonia to the rare extra-pulmonary infection, it is necessary to intervene more decisively, through the use of antibiotics, to avoid an outcome that is not certainly pleasant.
The percentage of death linked to the Legionella bacterium is strictly related to specific elements:

  • the initial health conditions of the patient
  • the criticality of the pathology
  • times and methods of initial intervention
  • where the bacterium was contracted

Based on the previous answers, there is a mortality rate of about 50% in all those immunocompromised patients who were not treated; about 15% in those situations that have received adequate treatment for the disease. Overall, the mortality linked to Legionella is on average under 10 units per 100 patients with legionellosis.
For this reason, the treatment of pipes, especially in air conditioning systems, is not only obligatory.

How to prevent it?
The legionella

Legionella can be avoided. Preventing leinfectionsfrom Legionella bacterium s possible as well as obligatory. There is some simple information to know and ways to proceed:

  • a well-designed technological system can definitely decrease the chance of water stagnation, especially where the water is either heated or vaporised/nebulized, such as air conditioning systems with air humidifiers, hydrosanitary systems, cooling towers, evaporative condensers, thermal facilities, swimming pools and hot tubs;
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Such as, for example, all air conditioning systems equipped with air humidifiers, plumbing systems, cooling towers and evaporative condenser, thermal plants, swimming pools, and whirlpool tubs;

  • adopting prevention systems such as scheduled maintenance, periodic disinfection, with the goal of hindering the proliferation and spreading of the Legionella bacterium in all those systems that are considered potentially risky.

The trace of Legionella is almost impossible to eradicate 100%. In a minimal part, it could be present in the system but not harmful. These actions can contribute significantly to the reduction and contrast of the spread and potential contamination by Legionella.

Legionella: treatment and prevention

Legionella can be countered by all those in charge of systems within various facilities. How can legionella be combated, thereby ensuring people a life free from the risk of contracting legionellosis?

A systematic process can be adopted to reduce the risk of contagion from the legionella bacterium:

It is essential to assign the role of responsible for checking against the legionella bacterium.

Ensure that the person appointed to the role of checker is properly trained and has the experience and competence to perform the function independently and authoritatively.

Train all staff about the risks of legionella and how crucial their contribution is to the checking process.

Ensure that water above 30 degrees is always moving.

Ensure that unheated water is always cold. The water should be around 20 degrees Celsius throughout the water system, even in containers, like tanks.

Run water from every outlet for a few minutes at 50/60 degrees every seven days, or anyway before the room, bathroom, is assigned (in the case of hotel facilities).

Remove all limescale from taps and showers

Consider the possibility of systematically sterilizing, every six months, both any evaporative cooling tower and the entire pipe system, and the air conditioning system.

Descaling and disinfecting boilers at least every 9/12 months.

Sterilize the high-temperature water production system with CL (chlorine) levels around 50 mg per liter for at least 2 to 4 hours following maintenance activity at the start of activities.

Periodically decontaminate water filtration systems, as indicated by the manufacturer (from one to three months).

Check all water tanks, cooling towers, and visible pipes once a month; ensure that the coating is intact and in the correct location.

Check the inside of the chilled water tank every 12 months and if there is material on the bottom, sterilize with 50 mg per liter of CL (chlorine) and then rinse.

Ensure the continuity of fluids in case of regular or extraordinary maintenance, at the end sterilize as above.

In the case of a thermal pool, ensure that: it is always managed with 2/3 mg per liter of CL or Br (chlorine or bromom) and pH values checked every 6/8 hours depending on attendance The water changed at least 50% every day, performing a backwash on the filtration system. Every 7 days disinfect the inside system.

Keep a daily log with values concerning water, temperatures, pH, and CL concentrations.

A systematic process can be adopted to reduce the risk of contagion from the legionella bacterium.

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