Not long ago, the unexplained pneumonia in Argentina really made the whole world nervous.

Fortunately, the real culprit was finally verified - the pathogen causing pneumonia was Legionella.

What is Legionella?

Why is it called such a "fierce"?

Where does it usually hide and how does it enter the human body?

　　Today, experts from the Environmental Sanitation Institute of the Beijing Center for Disease Control and Prevention have come to a thorough understanding of Legionella. Let's see if these corners of your home are properly disinfected.

　　ferocious-sounding Legionella

　　What the hell is a "ghost"

　　Legionella is a water-borne microorganism.

They are widely found in natural water sources and soils, and are often parasitic in hot and cold water piping systems.

Especially when the water temperature is 25 ℃ ~ 40 ℃, Legionella can survive for a long time.

Legionella bacteria are killed only when the water temperature exceeds 60°C.

　　Legionnaires' disease outbreaks occur all over the world.

In addition to Tibet, there have been reports of Legionella cases in my country, and cases of Legionella-like upper respiratory tract infection caused by air-conditioning system pollution have also occurred in Beijing.

　　Among them, Legionella pneumophila is the main pathogen causing Legionella pneumonia.

It prefers a humid and warm environment, so summer has become the season with the highest incidence of Legionella infection.

　　According to disease control experts, after infection with Legionella, the following two types of symptoms generally appear:

　　Legionella pneumonia is clinically characterized by symptoms of acute lower respiratory tract infection and is severe.

It has the typical characteristics of pneumonia, high fever, dyspnea, and respiratory distress syndrome, liver and kidney failure, etc. in severe patients. Legionella pneumophila infection is the main infection. If the treatment is not timely, the fatality rate is 15% to 30%. , the mortality rate of immunocompromised patients can be as high as 80%.

　　Pontiac fever is an influenza-like non-pneumonic Legionella infection that is mild.

The symptoms are like a cold, with fever, headache, muscle pain and other manifestations, and most of them can be cured by themselves in a short time.

　　Legionella is easy to cure.

Antibiotics can treat Legionella pneumonia, and antibiotics such as erythromycin, macrolides, and respiratory quinolones should be used in a timely manner as prescribed by a doctor.

However, once the time is delayed and the condition worsens, it may lead to irreversible consequences.

　　these corners

　　It's a hiding place for Legionella.

　　The study found that Legionella is ubiquitous in nature, and water is the natural habitat of Legionella. The survival and diffusion of Legionella in the environment must meet the following conditions: relatively static water environment, suitable temperature (20℃~40℃) , Appropriate pH (pH value 5-8.5), there are suitable parasitic microorganisms (amoeba, ciliate, etc.) in the environment.

　　Based on the above conditions: the central air-conditioning cooling water system, water storage system (fountain landscape, fire pool), industrial cooling water system, rain sprinkler, and atomization of homes, hospitals or office buildings are most susceptible to Legionella contamination.

　　Speaking of which, we have to understand how Legionella invades the human body.

Legionella is mainly infected through the respiratory tract. People inhaling water mist (aerosol) containing Legionella may be infected with this bacteria, resulting in the occurrence of Legionnaires' disease.

If you accidentally drink water containing Legionella, you will not be infected with Legionella.

　　Here comes the point!

Expert Tip: Although Legionella is not transmitted through human contact, its transmission route is more difficult to prevent.

For example: central air conditioners, air coolers, water vapor, etc., basically cover all public areas...

　　As the cooling device of the central air-conditioning ventilation system of public buildings, the central air-conditioning cooling tower is mostly built outdoors.

The cooling process will generate a large amount of water mist and spread to the surroundings. Improper design, operation and maintenance of the cooling tower will cause the Legionella bacteria in the cooling water to multiply and pollute the surrounding environment. The main source of Legionnaires' disease.

　　In addition, centralized hot water supply systems and household water storage independent water heaters usually operate at a temperature between 35°C and 50°C, which is suitable for the growth of Legionella; This increases the risk of Legionella contamination, and people who inhale the bacteria-laden mist in the shower can contract Legionnaires' disease.

　　Four high-risk groups

　　Most afraid of encountering Legionella

　　Anyone can get Legionella, but the following groups are at higher risk: men are at higher risk than women; people 50 years and older; long-term smokers, heavy drinkers; immunocompromised people, such as the elderly, young children, long-term use of immunizations Patients with suppressive drugs.

　　However, if you encounter Legionella, you will definitely be attacked by it.

Legionnaires' disease infection is caused by a combination of three factors.

First, the water mist contains Legionella bacteria, especially Legionella pneumophila; second, inhalation of these mists; and third, people who are susceptible to infection themselves.

　　At present, there is no corresponding vaccine for Legionnaires' disease. The main preventive measures should be taken to control Legionella contamination in cooling towers and hot water systems of air-conditioning systems, and at the same time strengthen self-protection of the population.

　　We can strengthen the sanitation management of air conditioning cooling tower systems and centralized hot water supply systems.

Especially hospitals, hotels, restaurants, office buildings and other public buildings with many susceptible people and high crowd density.

Continuous disinfection of cooling water, regular water quality testing, and risk assessment of key sites.

In addition, centralized hot water supply systems and storage-type water heaters used in households should regularly increase the water temperature for sterilization (above 60 ℃), empty the stagnant water in the pipes, and frequently clean the shower head.

　　Finally, exercising, quitting smoking and limiting alcohol, and improving your own immunity can also reduce the risk of disease.

　　Text/Reporter Li Jie