The same bacterium may have different consequences on health depending on the vunerability of individuals. Who needs to be prioritised for protection?
The gravity of a bacteriological infection on health depends on the immune system of each individual and the presence or absence of aggravating factors. Consequently, the elderly, immunocompromised individuals, persons who are convalescing, young children who still have an immature immune system, or even smokers are people who are more vulnerable and more exposed to risk. The presence of these populations in a home therefore requires increased surveillance of the water system and of the various installations. Some bacteria, such as legionellae, or pathogenic bacteria revealed by coliforms (including E. coli) can be the source of very serious infections, the mortality rate of which can reach 50% in these persons.
The immune system is the human body’s only line of defence against bacteriological attacks. It is generally very powerful and makes it possible to combat the majority of infections. However, in the event of genetic immunodeficiency or secondary immunodeficiency (i.e. following a disease), an infection which would be benign in a normal person can become very serious and be life-threatening. Those concerned are persons being treated with immunosuppressants or anti-cancer substances, persons who have been afflicted with diseases such as HIV, cytomegalovirus, hepatitis B, tuberculosis, cancers (leukemia, lymphoma, or any other type of cancers), or even persons who have undergone an ablation of the spleen or an organ transplant or an organ graft.
Regarding legionellosis, it is known today that immunodeficiency is an aggravating factor in close to 20% of cases*.
The immune system weakens with age. The elderly are therefore more exposed to a risk of infection from a bacteriological source than younger persons. This is why the residential care facilities for the elderly are high-risk locations for residents who have more chances to contract a severe form of infection, whether this be a legionellae contamination or coliform (including E. coli) contamination.
Specifically regarding legionellosis, studies show that the mortality rate rises to 50% for the elderly, as opposed to 10% for younger persons.
Young children have an immature immune system which does not allow them to defend themselves correctly against bacteriological attacks. Being more vulnerable, and more inclined to put their hands to their mouth, they must be the subject of a great deal of vigilance and increased hygiene measures, notably with regard to faecal contaminations due to coliforms (including E. coli). These can easily be found in bathing waters, wells and water tanks which can be used to water a garden or the like. Monitoring the water in these installations if there are young children present is a preventative measure which is vital to their safety.
Any person with a significant prior medical history can suffer from a general immunodeficiency or from an immunodeficiency of the specific area concerned.
A person suffering from a chronic respiratory disease, for example, is more exposed to a risk of contracting the severe form of legionellosis than a person in good health.
In the same way, a person suffering from Crohn’s disease (which attacks the digestive system), will be a lot more sensitive to a contamination with coliforms (including E.coli) and likely to develop a serious form of infection.
It is essential to particularly protect these persons by regularly monitoring the different installations in your water system.
In the specific case of legionellosis, studies show that smoking is a very significant aggravating factor in the contraction of the disease. In France, for example, where it is obligatory to declare the disease, close to 44% of persons afflicted each year are smokers. This aggravating factor can be compounded by all the others, which are: age, sex (men are affected more than women), the existence or absence of a history of respiratory ailments, diabetes, or immunodeficiency.
What consequences does a bacteriological contamination have on health?
An excessively high concentration of bacteria in the water system can become harmful to health and bring about illnesses which are more or less serious depending on a person’s vulnerability.
Legionellae are responsible for Legionnaire’s disease, or legionellosis, an infectious respiratory disease which can be fatal in 10% to 50% of cases.
The bacteria stemming from faecal contaminations, indicated by the presence of coliforms (including E. coli) can be responsible for infections ranging from gastroenteritis to septicaemia. They can bring about serious consequences.
I live, or a member of my family lives, in a residential care facility for the elderly. - Can I check the facility’s water system?
In certain countries, regulations oblige publicly accessible establishments and in particular residential care facilities for the elderly, to check for the presence of legionellae once per year. However, this is unfortunately not always put into practice and this is still very insufficient in the face of the reality of the risk incurred by the residents of these establishments who are already vulnerable. The elderly constitute a population which is particularly vulnerable to the legionellae risk.
My children use the showers and dressing rooms of their sports club or their educational establishment. Are they safe?
Depending on the country, the educational establishments or establishments which receive children can be submitted to a health risk monitoring regulation. It is necessary to be extra vigilant before the beginning of the academic year. The summer holidays are a period which is conducive to the development of bacteria in unused installations. Such installations must be monitored without fail before the beginning of the academic year in order to guarantee the safety of the children and other users.
What should I do in the event of contamination?
This depends on the point of contamination, the pathogenic bacteria responsible, and its level of concentration in the water.
In the event of contamination with legionellae, it is recommended that you contact the manager of the water system in order to have a professional engaged. He/she will carry out a high-temperature heat treatment and/or a chlorine chemical treatment in order to eliminate the bacteria. However, it is very difficult to eradicate legionellae completely. There are frequently recurrences, which make it necessary to regularly monitor your water system once it has been contaminated.
If you suspect you are exhibiting the symptoms of legionellosis (high fever, cough, muscular pain, headaches…), contact your doctor. Depending on the country, legionellosis may be a disease which must be declared by law. For example, in France, it gives rise to a medical and environmental inquiry by the Agence Régionale de Santé (ARS – Regional Health Agency) to identify the source of contamination.
In the event of your running water system being contaminated with coliforms (including E. coli), it is recommended that the water not be used for drinking, cooking or for cleaning teeth. It is advisable to contact the system manager immediately, who will inform you of the protocol to be followed in accordance with the instructions of the responsible health authorities.