As the weather gradually gets hotter, people turn on their air conditioning to cool off. In Chengdu, Sichuan, a citizen contracted severe pneumonia after turning on air conditioning that had been sealed off for a year. Why did this situation occur? How to get cool properly in summer? The reporter interviewed Yu He, Deputy Chief Physician of the Department of Respiratory and Critical Care Medicine at West China Hospital of Sichuan University. This is a typical Legionella pneumonia. After being infected with Legionella, mild patients may experience symptoms such as fever, headache, and mild cough, while severe cases may develop pulmonary infections. ”Yu He explained that the air conditioning cooling tower, which had not been cleaned for a long time, was a breeding ground for Legionella bacteria. Suddenly opening it was like pressing a "bacteria launch button". The cold water inside the machine will atomize and turn into small aerosols, carrying a large amount of Legionella bacteria. Once inhaled, the body's immune system begins to fight back, resulting in corresponding symptoms. The survival and reproduction of Legionella require a warm and humid environment. Air conditioning cooling towers, shower heads, or hot water pipes that are not used for a long time can easily breed Legionella bacteria due to accumulated water. Fountain, humidifier, and hot water bath that are not regularly disinfected can produce Legionella aerosol. Yu He introduced that Legionella pneumonia is a serious lung infection caused by Legionella bacteria, which mostly occurs from June to September. Patients with underlying diseases such as chronic heart and lung diseases and immunocompromised individuals are prone to infection. The incubation period of Legionella pneumonia is generally 2 to 10 days. The main symptoms include respiratory symptoms such as high fever, severe cough, and difficulty breathing, as well as extrapulmonary manifestations such as headache, nausea, vomiting, diarrhea, and muscle soreness. In severe cases, it can even lead to respiratory failure, rhabdomyolysis, and acute kidney damage. How to prevent it in daily life? Yuhe suggests regularly cleaning the water source system. Cleaning and disinfecting equipment such as air conditioners, water heaters, and shower heads can prevent bacteria from accumulating in pipelines. During the cleaning period, it is important to wear a well sealed mask to avoid inhaling pathogenic bacteria. Long term unused faucets, showerheads, etc. should be drained of water for one or two minutes before use to remove any remaining contaminated water. In addition, the humidifier needs to be cleaned with purified water and changed daily. At the same time, keep the environment ventilated and dry, open windows for ventilation every day, and reduce the continuous closed operation of air conditioning. For susceptible populations, it is necessary to strengthen protection. Elderly people, chronic disease patients, and immunocompromised individuals should try to avoid contact with contaminated water mist as much as possible, "said Yu He. What are the precautions for cooling off in summer? Yu He introduced that before using the air conditioner for the first time, it is necessary to thoroughly clean the filter and condensate tray. It is recommended to set the air conditioning temperature at around 26 degrees Celsius, avoid direct cold air blowing, and ventilate every two to three hours of operation. If swimming, it is recommended to choose a swimming pool with standard disinfection to avoid inhaling water mist from spray cooling equipment. When engaging in outdoor activities, it is also important to avoid contact with unclean water sources such as standing water, fountain pools, and landscape pools. After playing in water, rinse your body promptly. Yu He reminds everyone that if they experience symptoms such as fever, cough, chest pain, and poor breathing during the use of air conditioning, it may not be a common cold and they should seek medical attention promptly to be alert to the occurrence of Legionella pneumonia. (New Society)