Microorganisms
The indoor air also contains bacteria, viruses and other microorganisms such as mold, which can cause infectious and allergic diseases. Bacteria and virus are transmitted by various means, including through the air, person-to-person, or by other means, such as insects and animals. Examples of infectious diseases include colds, influenza, measles, tuberculosis, and chickenpox. Hypersensitivity pneumonitis is an allergic inflammatory disease of the small air sacs (alveoli) deep in the lungs caused by hypersensitivity to mold, bacteria, or other small allergen particles (5um or smaller).
Many homes have whirlpool baths or hot tubs near them or part of the master bathroom, which can be a source Pontiac fever, folliculitis (an itchy skin rash caused by a bacterium called Pseudomonas aeruginosa), and respiratory illnesses such as bronchitis. Hot tubs and whirlpools can be particularly hazardous because resident may not keep the properly cleaned. Owners of hot tubs and whirlpools should be sure to obtain guidelines for homeowners developed by the National Spa and Pool Institute, which addresses how to keep their hot tubs and whirl pools clean.