Legionella: The Silent Killer Lurking in Warm Water

Legionella is a disease-causing pathogen that thrives in warm and humid environments (25-42°C). It spreads through aerosolized water, and when water droplets containing the bacteria are inhaled into the lungs, it can cause a severe illness known as Legionnaires' disease.

It is highly deceptive, as the initial symptoms of Legionella infection resemble those of the flu (fever, cough), making it easy to misdiagnose! The disease can develop into severe pneumonia within 48 hours, leading to respiratory failure and multi-organ damage, with a fatality rate as high as 10-30%!

Those with weakened immune systems (the elderly, smokers, and individuals with chronic diseases) are the most susceptible!

The most common hiding places for Legionella are air conditioners that have not been cleaned for a long time, public hot springs, showerheads that haven’t been used in a while, garden fountains, and humidifiers that are not regularly cleaned. These sources can release bacteria into the air.

Symptoms can appear 2-10 days after infection, including persistent high fever (over 39°C), severe cough, chest pain (including coughing up blood), shortness of breath, and confusion.

Note: Common antibiotics (such as penicillin) are ineffective against this disease, and delayed treatment can be fatal!

How to “Fight” Legionella Bacteria

• Clean devices and water systems: Regularly clean air conditioners. Before using an air conditioner each year, have a professional clean it thoroughly. Typically, remove the filters every month and wash them with water hotter than 70°C and a neutral cleaner. Pay attention to cleaning water sources, removing dust and debris from faucets or showerheads that haven’t been used for a long time, and flush out any stagnant water before use. Replace the water in humidifiers daily and disinfect it once a week with a diluted chlorine-based disinfectant.

• Precautions when outdoors and unusual physical symptoms: Be cautious when enjoying outdoor activities. Choose locations with good hygiene conditions and ensure frequent disinfection when using hot springs. Wear a mask and gloves when gardening or handling soil. Be alert to any unusual physical symptoms. If you suddenly experience high fever, cough, or diarrhea after using air conditioning or taking a hot spring bath, seek medical attention immediately and inform your doctor of your symptoms.