According to Professor Sebastian Lemmen, who works in the central department for hospital hygiene and infectious diseases at the University Hospital Aachen, concerned swimmers can be reassured. “It can be assumed that due to chlorination and the extreme dilution by the mass of water in the swimming pool, sufficient transmission of pathogens that could lead to an infection is almost impossible,” he says. For almost all infectious diseases, a sufficient amount of pathogens, known as the infectious dose, is needed for an infection such as the flu or diarrhea to occur in the recipient. This is only theoretically conceivable in a swimming pool. “To my knowledge, a swimming pool has never been described as a source of an outbreak in the literature either.”
Two billion microorganisms
It’s interesting to know that every person is inhabited by microorganisms, which are released into the bathwater during bathing. “So each of us releases about two billion microorganisms with each bath. Most of them come from our skin and are harmless bacteria,” informs the German Environment Agency in its free brochure “Around the Bathwater.” It is possible for microorganisms, some of which are less harmless and theoretically can cause diseases such as gastrointestinal diseases, skin diseases, eye diseases, ear diseases, and respiratory tract diseases, to be introduced into a swimming pool. Waterborne pathogens exist among bacteria, viruses, and multicellular organisms. However, they must first survive in chlorinated water, and an infection, such as a Salmonella infection, would typically require 100,000 to 10 million bacteria to trigger it.
