Legionnaires' disease: what it is, symptoms, treatment

Going to the pool or spa can turn out badly. If you feel unwell after visiting these places and have symptoms similar to an acute respiratory infection, it is important to seek medical attention. It could be a serious illness such as legionellosis.

Inhaltsübersicht

What is Legionnaires’ disease?

doctor, researcher of the Saratov MSC of hygiene FBUN.

“Legionellosis or Legionnaires’ disease is an acute sapronous infectious disease, the causative agent of which is bacteria of the genus Legionella.”

The pathology officially originated in 1976. At that time in Philadelphia, a convention of veterans of the American Legion (a public organization of veterans of the U.S. Armed Forces) was held. An outbreak of this infection, later called Legionnaires’ disease, occurred among them.

In 1979, the first case was recorded in the USSR. At the moment this disease is registered in 19 regions of Russia, including the central regions. According to WHO data, the highest prevalence of legionellosis is observed in the USA, Australia and European countries.

The natural reservoir of legionella is fresh water bodies at temperatures of 25-45 degrees Celsius. However, among the annually registered cases of legionnaires’ disease infection, the cause of most of them is not natural water sources, but technical installations associated with the use of water supply system. These include:

water supply pipes;
air conditioning units;
fountains;
showers;
swimming pools;
Jacuzzis;
boilers.

These provide a comfortable environment for the growth of colonies of the pathogen. Although there are also species of Legionella (L. longbeachae), which as a habitat use artificial soil for growing flowers in pots.

Infection occurs by airborne droplets, usually through inhalation of fine droplets of contaminated water with the air. It should be noted that this disease is not contagious, that is, a sick person does not pose a threat of infection to others.

Symptoms

Legionnaires’ disease does not have specific symptoms. Two forms of clinical manifestations of legionellosis are distinguished. These are non-pneumatic and pneumatic. Despite the fact that at the moment there are approximately 50 species of legionellae, the disease runs through the scenario of one of the two clinical forms.

In the non-pneumatic form, after the incubation period (up to 48 hours), there are symptoms similar to ARVI. This is a subfebrile fever, chills, pain in the muscles and joints. This course of the disease is not life-threatening, the symptoms resolve on their own in a few days, without causing complications.

The incubation period in the pneumatic form of legionellosis can vary from two days to two weeks. After which symptoms of acute pneumonia and pleurisy, intoxication (febrile fever), myalgias develop. There may be dyspnea, a feeling of painful pressure in the chest, coughing, both non-productive and with the discharge of sputum, including with an admixture of blood.

In severe cases, pulmonary insufficiency may develop. When visual methods of examination on the images can be seen signs of destruction and abscess of lung tissue. Functional disorders are not excluded:

gastrointestinal tract (pain, nausea, vomiting, diarrhea);
cardiovascular system (inflammation of the heart membranes, decreased blood pressure, bradycardia);
central nervous system (impaired coordination of movement, consciousness).

According to WHO, mortality from legionellosis is 5-10% and occurs due to the development of multi-organ failure, central nervous system damage.

How it differs from the common cold

The main difference is that without therapy, the patient’s condition usually worsens during the first week. There may also be sputum with traces of blood or hemoptysis, as well as an increase in body temperature up to 40 degrees.

Who gets sick most often?

general practitioner of the Department of Family Medicine of JSC “Medicine” (Clinic of Academician Roitberg)

“Legionella microorganisms can live in various aquatic environments such as ponds, rivers, lakes. It is also found in artificial water supply, air conditioning and refrigeration systems. Given that many of us are often in rooms with artificial air conditioning systems, that means that virtually every office worker is at risk.”

The risk of infection is increased in people over 50, smokers or those who abuse alcohol. Other factors that increase the likelihood of the disease are chronic lung, heart, kidney or liver disease, and decreased immunity due to cancer, diabetes, HIV or taking immunosuppressive drugs.

Anyone who falls into one of these groups should be especially careful in air-conditioned rooms, swimming pools with public showers.

If you spend a lot of time in the office, try to choose a workplace as far away from air conditioning as possible. Discuss this possibility with your management.

Which doctor treats this condition?

If you suspect that you have legionnaire’s disease, you should immediately consult a general practitioner or infectious disease specialist. Also legionellosis is treated by a pulmonologist. This specialist deals with diseases of the respiratory organs (bronchi and lungs). In some cases, the help of a radiologist may be required.

Diagnosis and treatment

To diagnose the disease, various methods are used, such as:

blood tests for antibodies to Legionella bacteria;
sputum or urine culture for Legionella bacteria;
PCR to determine the DNA of Legionella bacteria;
X-ray or computed tomography (CT) scan of the chest to detect changes in the lungs.

Treatment for Legionnaires’ disease is based on taking antibiotics that kill Legionella bacteria or inhibit their reproduction. Usually the course lasts from seven to 14 days, depending on the severity of the condition and the response to therapy.

In addition, patients are prescribed symptomatic medications such as antipyretics, analgesics, cough suppressants and oxygen therapy.

Under no circumstances should you prescribe treatment for yourself. The pneumonia that develops with legionellosis is similar in appearance to regular pneumonia. But it also has its own specifics, which can only be determined by a specialist.

The main method of treatment of this disease is antibacterial therapy. Therefore, fluoroquinolones, macrolides are highly effective. The most commonly used drugs are levofloxacin, erythromycin, azithromycin, clarithromycin.

In most cases, one of the above means is sufficient to treat the disease, but in severe cases, the additional use of an antibiotic belonging to the group of ansamycin (rifampicin) is allowed. With adequate treatment, recovery occurs within 7-10 days.

Preventive measures

Prevention of Legionnaires’ disease is to prevent the growth and spread of Legionella bacteria in aquatic systems. To accomplish this, the following measures should be followed:

Keep water temperatures below 20 degrees or above 60 degrees, as Legionella bacteria multiply in warm, contaminated water;
clean and disinfect water supply, air conditioning and cooling systems regularly;
avoid stagnant water in pipes, tanks and filters;
renew water in decorative fountains (at least once a week);
use chlorine or other chemicals to kill Legionella bacteria;
avoid contact with fine water dust from fountains, hot tubs, or air conditioners;
use sterile water instead of tap water when using an inhaler or vaporizer;
Before using public showers (at a gym, swimming pool or hotel), carefully examine their condition. If there is dirt or rust, you should refuse to use it;
pregnant women and small children should not take hot baths or swim in public pools.

Remember that Legionnaires’ disease is a serious disease that can have serious consequences for human health and life. Therefore, it is important to timely detect and start treatment, as well as to take measures to prevent it.

Also, the prevention of legionellosis is carried out in the framework of sanitary and epidemiological supervision. The main method is periodic cleaning of means to maintain an optimal microclimate in buildings and facilities, swimming pools, fountains, boilers.

Apply not only chemical (chlorine-containing agents), but also physical (ultraviolet treatment, ionization of water, heating water over 65 degrees) methods of disinfection.

It is also necessary to regularly (at least twice a year) sampling of water from the centralized water supply system for microbiological examination.

Remember that bacteria of the genus Legionella can be in tap water for up to a year, and in distilled water – from two to four months. At the same time, they die in one minute when using a disinfectant (which has up to 70% alcohol in its composition).