Hot Tub Lung

Hot tubs have been shown to be associated with disease. A well documented example of this is Hot Tub Lung (Mycobacteria induced respiratory illness) as a result of hot tub use.

Hot tubs are a favorable environment for these thermophillic bacteria and their disinfectant-resistant nature can make them a potential health risk for bathers. Once established, a Mycobacteria infection can also be very difficult to treat with antibiotics. The Center for Biofilm Engineering at Montana State University has developed hot tub simulations to study the efficacy of chlorine as a disinfectant against Mycobacterium fortuitum.

Bacterial samples were taken from three locations: from the bulk water, from coupons mimicking hot tub surfaces such as walls, and from inline hot tub filters. In the control, it was determined that colonies were particularly prevalent in the bulk water and on the inline filters. The main result was that while chlorine worked fairly well in a clean system inoculated with an organism, if fouled filters were moved to a clean system (analogous to a poor cleaning or just a spray down of the filter) with no new inoculation, M. fortuitum would not just survive but would actually GROW in the presence of chlorine. This enhances the chances for a user to experience repeat exposure and eventually develop a Type III Immunopathology response, hypersensitivity pneumonitis.

Chronic hot tub use can lead to inoculation of the bacterium resulting in the development of antibodies circulating in the blood stream. At a certain threshold, an individual may enter the hot tub and develop an immune response to the bacteria, as the circulating antibodies bind to the antigen. When the antibodies bind to the antigen large immune complexes form that cannot be cleared and they are subsequently deposited in vessel walls and there is an inflammatory response.

The center at MSU suggested that hot tub filters are really tricky to effectively clean due to all of the folds and even an aggressive cleaning could result in this occurrence.

All that said and I will be hot tubbing sometime this winter season!