Hot Tub/Whirlpool Bacteria Studies

Texas Study

The Boulder Study

Jewish Study

Quote from Jewish Study: "Because luxury items like hot tubs are becoming more common, I believe there will be an increasing recognition and understanding of the risk associated with their use among doctors and consumers."

Mayo/CDC Study - "Emerging Infectious Diseases Journal"

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Cryptosporidiosis - Chlorine resistant

Giardiasis

 Conditions

During recent years, association of hypersensitivity pneumonitis disease with a different species, Mycobacterium avium complex (MAC), from hot tubs, whirlpool baths, and spas has also been identified, sometimes referred to as "hot tub lung" (Capelluti et al. 2003; Grimes et al. 2001; Rickman et al. 2002; Scully et al. 1997). In these hot water bathing tubs, water may be agitated by powerful jets of air or water that produce bubbles and hence aerosols of water droplets. MAC grows well in the high water temperature of the indoor hot tub. The combination of MAC organisms' growth and jet aerosolization and subsequent inhalation of large amounts of MAC presumably leads to the development of this disease. Hot tub lung appears to be hypersensitivity pneumonitis to MAC aerosol rather than a direct infection of the lung, although this subject is still a matter of debate (Aksamit 2003; Embil et al. 1997). Interestingly, there have been no documented cases of hot tub lung with outdoor hot tubs.

In hot tub lung, pulmonary function tests were mainly restrictive with occasional obstruction (Anonymous 2000; Kahana and Kay 1997; Khoor et al. 2001; Mangione et al. 2001; Mery and Horan 2002; Rihawi et al. 2004). Chest radiography shows diffuse infiltrates, and high-resolution CT of the chest shows ground glass opacities and micronodules (Pham et al. 2003). Sputum culture was positive for MAC in about 70% of the patients; transbronchial biopsy and bronchoalveolar lavage cultures increased the yield further (Anonymous 2000; Kahana and Kay 1997; Khoor et al. 2001; Mangione et al. 2001; Mery and Horan 2002). Hot tub water usually grows MAC. The histopathologic findings reveal discrete nonnecrotizing granulomas with centrilobular and bronchiolocentric distribution. The granulomas described in hot tub lung were more exuberant and well formed than those seen in typical cases of hypersensitivity pneumonitis from other causes.

There is no standard approach to treatment of hot tub lung. Case reports describe significant improvement with removal from exposure to the hot tubs. Oral corticosteroids, antimycobacterial therapy, or both have also been used. The expected course of this disease after the above measures is recovery without relapse. Measures proposed as being helpful in prevention include better ventilation of the hot tub room, frequent cleaning of the hot tub, frequent change of hot tub water, and use of disinfectants such as chloramines, bromine, and ultraviolet light.

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Bath residue adheres to and builds up on surfaces it touches. You can see it on your bathtub surface and scrub it clean, but you can neither see it nor reach it on the inside surfaces of the piping of conventional whirlpool baths and the air channels of air tubs. Bath residue becomes a smorgasbord for infectious bacteria, which rapidly multiply in the warm, dark, moist environment of inaccessible pipes and air channels. Matrices of bacteria called "biofilm" develop that are highly resistant to disinfectants. Circulating common household products such as detergent or bleach or "specially formulated" products through piped systems will NOT remove the residue buildup and will NOT kill biofilm. The inability to effectively clean and sanitize piped systems and air tubs exposes the bather to dangerous pathogens associated with skin problems, urinary tract and vaginal infections, respiratory illnesses, including pneumonia, legionnaires disease and other maladies. Because piped whirlpool baths and air tubs cannot be effectively cleaned and sanitized, they may present a health risk to the user.

The Organization responsible for setting whirlpool bath cleaning and sanitation standards is the American Society of Mechanical Engineers (ASME/ANSI A112.19.7M-1995; generally called "the ANSI committee"). The committee is populated in part with representatives of piped whirlpool bath manufacturers. The committee has adopted two weak standards regarding water retention and cleaning.

Water Retention --- Section 5 allows a piped whirlpool system to retain as much as 1.5 fluid ounces of water for each jet and suction fitting. This means that a typical 6-jet system with one suction fitting can retain 10.5 fluid ounces (over one cup) of dirty bath water when the tub vessel itself is fully drained. We know from grade school that stagnant water is associated with germs. The whirlpool bath industry acknowledges that fluid retention is unsanitary. Why else would the committee set maximum limits? However, would you pour a cup of left over dirty bath water into a fresh tub of water before you bathed in it?

Some manufacturers dubiously claim that their systems fully drain. Manufacturers routinely have their whirlpool systems tested for water retention by the International Association of Plumbing and Mechanical Officials (IAPMO) through various approved testing laboratories. If a manufacturer claims that its whirlpool system does not retain any water, ask the manufacturer for its IAPMO test results.

In any case, hard water scale deposits and soap scum residue build up on the interior surfaces of the piping, regardless of water retention. Witness the 'ring around the tub' when you drain it after bathing. Imagine how your bathtub would look if you took a bath with soap every day for two weeks without cleaning the tub (90 days under the ASME/ANSI standard minimum), even though you had drained it after each use. Residue collects in the pipes just like it does on the tub surface, but you can't see it inside the pipes---it's out of sight and out of mind.

Cleaning --- Section 4.4.2 says to flush the circulation system at least every 90 days with fresh water and sanitize with chemicals as recommended by the manufacturer and requires that manufacturers' operating instructions have a warning in bold print that informs the user to flush the circulation system.

The "sanitizing chemicals" manufacturers typically recommend are dishwashing detergent and/or bleach. However, evidence developed in litigation as well as statements by other manufacturers reveals a complete absence of any testing to support the committee's 'standard' or the manufacturers' recommendations. To the contrary, sound science, practical experience and common sense show that merely flushing the system with detergent or bleach will not thoroughly clean and sanitize the system. Scrubbing a surface with detergent and bleach is one thing, but trying to remove oily residue by merely running highly diluted detergent and bleach through piping is quite another. Could you clean the soap scum film off your shower door or bathtub surface once every 90 days (or even once a week) without scrubbing it? Instead of adopting a real cleaning standard, scientifically tested and uniformly applied, the committee passed the buck back to each manufacturer.

Section 3 of the whirlpool bath standard defines "circulation system" to include all air induction piping. The air piping however on most systems is designed in such a way that bath water will backfill into the air lines and deposit residue when the pump is deactivated, but no fluid will circulate through the air lines when the pump is engaged. Therefore, even if detergent, bleach, or any other product would thoroughly remove residue and kill bacteria, it cannot be circulated through the air lines of most systems, making the entire circulation system of most whirlpool baths uncleanable by any means.

Owners of piped whirlpool baths should locate their product literature and compare the manufacturer's cleaning recommendations with those in the ASME/ANSI Standard. If the product literature isn't available, contact your manufacturer's customer service department and request current literature.

• Does the literature contain a "warning in bold print that informs the user to flush the circulation system"?
• If so, ask the manufacturer why the warning is there and what might happen if the warning is not followed. Ask the manufacturer, if the warning has anything to do with a risk of bacterial infection.
• If the bold warning isn't in the product literature, ask why.
• Ask if the manufacturer has any testing reports that support the effectiveness of its published cleaning recommendations and request a copy.
• Ask the manufacturer how much water its systems retain and ask for its IAPMO approved testing to verify the manufacturer's answer.

Q & A

Do manufacturers have any testing to back up their cleaning recommendations?

No manufacturer has any such testing.

How do you know that flushing automatic dishwashing detergent (ADD), bleach or other products through the pipes is not effective?

Reports of frustrated whirlpool bath owners follow a common refrain, "I've tried those and other products, and black stuff still comes out of the jets." No whirlpool bath manufacturer to our knowledge has any testing to prove the efficacy of its flushing instructions. To the contrary, scientific evidence points to the practical impossibility of maintaining a piped system at a safe level of sanitation. Here's what an expert says:

Connie M. Hendrickson, Ph.D. (Biochemistry)
Certified Professional Chemist
Specializes in commercial cleaning applications

"ADD (automatic dishwashing detergent) is often recommended by whirlpool bath manufacturers but falls far short of a complete cleaning. ADD has no component for dissolving scale. Bleach reacts with some ingredients of whirlpool bath soil, but not as a cleaner. If anything, bleach action will make this type of soil more insoluble in water. Bleach does destroy accessible bacteria or fungal material, but will not kill those deep in crevices and protected by oily material, because bleach does not dissolve oil or scale. In concentrations generally recommended by manufacturers (4 oz in 50-100 gal. of water), bleach will be only marginally effective as a bactericide, if at all. Baking soda [sodium bicarbonate] in its powdered form is commonly used as a household odor control agent. Dissolved in water, it is a weak base, a kind of chemical which can dissolve a very small amount of oily material but has no effect on odor control. It also has no effect on scale, as scale itself is formed in a basic medium. Vinegar [acetic acid] will also dissolve a small amount of accessible oily soil if used in high concentrations. It will dissolve some scale but cannot act on scale protected by heavy oily deposits. Based on my experience in the cleaning industry, piped bath systems can not be cleaned by the simple circulation of ordinary household cleaners."

What evidence shows that piped whirlpool circulation systems promote the growth of infectious microorganisms?

Here's what the scientists say:

Rita Moyes, Ph.D.
Director of the Microbiology Laboratory
Texas A&M University

"Since December 1998, I have been conducting tests on the microbial content of whirlpool bath water from piped whirlpool baths in homes and hotels across the nation. These tests were conducted on aseptically collected samples sent to me in sterile containers, which were then subjected to standardized laboratory tests to assess relative bacterial numbers. All piped whirlpool bathtubs present identical dangers of microbial propagation because the biofilms which constitute the bacterial environment collect and remain on the interior of the piping. All tub samples tested contained microorganisms including enteric organisms, fungi, Pseudomonas sp., Legionella sp., and Staphylococcus aureus. The enteric bacteria cause 30-35% of all septicemias (blood infections), >70% of urinary tract infections, and many intestinal infections. Pseudomonas aeruginosa has been implicated in infections of the respiratory tract, burn wounds, urinary tract, ear, and eye. It can also cause bacteremia, endocarditis, and gastroenteritis. All Pseudomonas sp. can cause opportunistic infections in immunocompromised patients. Legionella is the causative agent of Legionnaires' disease (with a 20% mortality rate) and Pontiac fever. Staphylococcus aureus causes a number of cutaneous infections including impetigo, folliculitis, furuncles, carbuncles, and wound infections. S. aureus also release a toxin, which is responsible for scalded skin syndrome, toxic shock syndrome, and food poisoning. S. aureus is also an etiological agent for bacteremia, endocarditis, pneumonia, empyema (pus in the plural cavity), osteomyelitis, and septic arthritis. This was just a preliminary study and I tested for only a few types of organisms but it should be obvious that the presence of these microorganisms illustrate the potential health risk the bather exposes themselves to upon each entry into the tub."

"Any piped system will propagate harmful microbes which can and do cause sickness and death in humans."

"Due to the presence of pathogenic and potentially pathogenic organisms, education of the public on the hazards of piped whirlpool bathtubs use should become a priority."

Note: Dr. Moyes tested over 40 whirlpool bath water samples from homes and hotels across the country. All of them tested positive for at least one type of (and frequently more) pathogenic bacteria or fungus.

William J. Costerton, Ph.D., microbiologist
Director of the Center for Biofilm Engineering (CBE),
Montana State University

"The CBE is the premier research institution for the study of the slimy surface aggregations of bacteria called biofilms. I coined the term 'biofilm' . . . in an article in Scientific American (Feb. 1978), and have since published more than 400 research papers on this topic." Commenting on a controlled study of a Jacuzzi piped whirlpool bath by a CBE research engineer, Dr. Costerton reports:

"The data summarized in this report show, with scientific certainty, that biofilms are formed on the surfaces of the pipes that feed the jets, and that these biofilms contain very large numbers (hundreds of thousands of cells per square centimeter) of heterotrophic bacteria, including many cells of Pseudomonas aeruginosa. This test reconfirms the widely known fact that biofilm forms in piped systems of this nature and it will form similarly in any whirlpool tub that humans use for bathing which utilize a piped circulating system. Irrespective of how well the system drains, water adheres to the interior pipe walls and this is the initial mechanism by which the bacteria are able to attach to the surfaces and thereafter begin the process of forming biofilm. Because small particles are always entrained in bubbles, the whirlpool jets produce an aerosol that contains bacteria from these biofilms, and direct observations of this test system have shown that the aerosol contains sessile bacteria in matrix-enclosed biofilm fragments. It is therefore a scientific certainty that any person using this whirlpool bath, with the jets in operation, would be exposed to airborne biofilm fragments containing pathogenic bacteria. While it cannot be predicted with certainty which bathers will develop overt pulmonary disease, it can be stated with scientific certainty that all bathers will have been exposed to the potentially hazardous aspiration of biofilm fragments as a result of using this whirlpool bath."

"The chance of infection during any given bath cannot be predicted with mathematical precision because contact with, or duration of, the bacteria is a random event depending on many variables. However, it is scientifically certain that all bathers are exposed to an environment conducive to infection and - if they are bathing in the typical nude fashion and having no device filtering the air they breathe - which, of course, is the usual procedures, they are taking no precaution against infection in an environment where they are surrounded by microscopic disease causing organisms and, unbeknownst to them, they should be taking precautions."

"Our experience in the cleaning of biofilm colonized pipes, for the re-use of these systems in laboratory experiments, indicates that a 24-hour exposure to bleach (at a sustained hypochlorite concentration of more than 2%) is necessary to kill bacteria in biofilms and to remove the biofilm matrix from these surfaces. If the matrix material is not removed, the regrowth of the biofilms is very rapid (less than 2 days), while perfectly clean surfaces will re-foul in +/- 4 days. Because these effective measures would be beyond the resources of even the most fastidious spa owners, there is essentially no way to keep units designed in this way free from biofilms that constitute a real risk to human health."

From a 1995 report in Lancet, "Pseudomonas aeruginosa wound infection associated with a nursing home's whirlpool bath":

Whirlpool baths are fitted with hydrojet circulation and/or air induction bubble systems. Water in a whirlpool bath, unlike a spa pool, is not filtered or chemically treated but the bath is drained and cleaned between each bather. This is, we believe, the first report of Pseudomonas aeruginosa wound infection associated with the use of a whirlpool bath in a nursing home. Microbiologically confirmed infections with P. aeruginosa ofidentical [sic] antibiotic sensitivity patterns arose in one week in wounds of four of 24 residents who used a whirlpool bath from which P. aeruginosa was also isolated. P. aeruginosa was not isolated from the wounds of a [sic] further seven residents who did not use the whirlpool bath. The incident control team advised that use of the whirlpool bath should be restricted to continent residents with intact skin, and that the bath should be cleaned with a degreasing agent and disinfected with hypochlorite between use by individual residents. The hazard of infection posed by whirlpool baths, particularly in nursing homes, needs to be assessed. National guidance for their cleaning, maintenance, and disinfection is required."

Elson Zazulak, Certified Public Health Inspector
Environmental System Health Officer, Capital Health Authority
Alberta Province, Canada:

"Since 1993 the Capital Health Authority has been monitoring drain and fill whirlpool bathtubs in public facilities such as nursing homes and extended care facilities. . . . The bacterial content of the water in drain and fill whirlpool bathtubs in these facilities is periodically tested because it has been known for a number of years that these kinds of tubs propagate and circulate various pathogenic bacteria, including pseudomonas, legionalla [sp], staphylococcus and E. coli."

"This agency [Capital Health Authority] has conducted field trials on Quaternary ammonium compounds, Bleach and Virox and the only chemical we have found which effectively reduced pathogenic bacteria in individual hydrotherapy tubs is Quaternary ammonium compounds."

"A Whirlpool Of Bacteria", Nursing Times, June - 1989:

"The ambience for survival of Pseudomonas aeruginosa in the pump and pipework of the therapy bath [speaking about a whirlpool bath] is clear, and it is significant that the organism continued to survive following the introduction of the manufacturer's recommended detergent, degreasing agent and methods of use."

Canadian Infection Control Guidelines for Long-Term Care Facilities, Rev. 1993 (pp. 8-9):

"Single-use recirculating hydrotherapy equipment, such as bath tubs, century tubs, hubbard tanks and whirlpools, must be drained after each resident use. Pseudomonades, legionellae and other bacteria thrive in the warm, moist, dark environment of the internal plumbing of these units. Given the opportunity, they may form a semi-permanent biofilm, which can provide a never-ending reservoir of bacteria within the system. It is necessary to disinfect all components of the unit, including the basin, the internal plumbing and the lift chair with a disinfectant-detergent after every bather (emphasis added). Prior to the first use of the day, it is necessary to disinfect the entire system . . . as organisms may have survived the disinfection process of the previous day and multiplied. " (emphasis added)

E. Tredget, MD et al., "Epidemiology of Infections with Pseudomonas aeruginosa in Burn Patients: The Role of Hydrotherapy", Clinical Infectious Diseases 1992
Outbreak of pseudomonas infection, including multiple deaths, in burn treatment unit was attributed to hydrotherapy tubs (piped whirlpool baths) despite rigorous disinfectant procedures after each use, leading to the discontinuance of hydrotherapy.

"P. aeruginosa is a opportunistic gram-negative pathogen that thrives in an aquatic environment and has been identified as the cause of numerous outbreaks of skin infection transmitted to unburned patients and health care workers by medical equipment used for hydrotherapy. Because the organism was recovered from hydrotherapy equipment, this form of treatment was stopped and the strain of P. aeruginosa associated with the epidemic was eradicated . . . This outbreak occurred despite weekly surveillance cultures of this equipment and the use of standardized protocols for its disinfection between uses."

Glenn A. Bodnar, Engineering Unit Leader
Drinking Water Section of the Water Quality Control Division,
Colorado Department of Public Health and Environment
(Commenting in a February 13, 1995 letter on fill-and drain whirlpool baths in commercial facilities)

"Public baths that are not properly cleaned and disinfected have been the cause of skin rashes and disease such as pseudomonas. We have also received complaints of gastroenteritis and diarrhea when some of the contaminated water had been accidentally consumed."

"It is common that the maintenance people responsible for these baths properly drain and disinfect the basins, but do not properly clean the re-circulation system and air line. Bacteria are known to be present in this part of the baths. Even when you clean the basin and fill it with clean water, the bath is immediately contaminated when the pump is turned on."

Kevin L. Winthrop, M.D., et al., "An Outbreak of Mycobacterial Furunculosis Associated with Footbaths at a Nail Salon", The New England Journal of Medicine, Vol., 346, No. 18, May 2, 2002, www.nejm.org; (Note that the footbaths described in the following abstract are equipped with 2-jet piped whirlpool bath systems.)

Source Information: From the Epidemic Intelligence Service, Epidemiology Program Office (K.L.W.), and the Division of AIDS, Sexually Transmitted Diseases, and Tuberculosis Laboratory Research, Tuberculosis/Mycobacterial Branch ( M.Y.), Centers for Disease Control and Prevention, Atlanta; the Division of Communicable Disease Control, California Department of Health Services, Berkeley (K.L.W., J.E., D.J.V.); and the Santa Cruz County Department of Health, Santa Cruz ( M.A., I.S., D.G.).

"Background: In September 2000, a physician in northern California described four patients with persistent, culture-negative boils on the lower extremities. The patients had received pedicures at the same nail salon. We identified and investigated an outbreak of Mycobacterium fortuitum furunculosis among customers of this nail salon.

Methods: Patients were defined as salon customers with persistent skin infections below the knee. A case-control study was conducted that included the first 48 patients identified, and 56 unaffected friends and family members who had had a pedicure at the same salon served as controls. Selected M. fortuitum isolates, cultured from patients and the salon environment, were compared by pulsed-field gel electrophoresis.

Results: We identified 110 customers of the nail salon who had furunculosis. Cultures from 34 were positive for rapidly growing mycobacteria (32 M. fortuitum and 2 unidentified). Most of the affected patients had more than 1 boil (median, 2; range, 1 to 37). All patients and controls had had whirlpool footbaths. Shaving the legs with a razor before pedicure was a risk factor for infection (70 percent of patients vs. 31 percent of controls; adjusted odds ratio, 4.8; 95 percent confidence interval, 2.1 to 11.1). Cultures from all 10 footbaths at the salon yielded M. fortuitum. The M. fortuitum isolates from three footbaths and 14 patients were indistinguishable by electrophoresis.

Conclusions: We identified a large outbreak of rapidly growing mycobacterial infections among persons who had had footbaths and pedicures at one nail salon. Physicians should suspect this cause in patients with persistent furunculosis after exposure to whirlpool footbaths."

What about air tubs that don't circulate water, but only blow air into the bath water? Aren't they touted as being free from bacterial contamination?

These systems employ air channels and/or false tub bottoms to force air into the bath water, creating a bubbling effect. However, water backfills into the channels when the air-system is deactivated. When backfilling occurs, bath residue adheres to and builds up on the inside surfaces of the channels, creating the same host environment for infectious microorganisms as ordinary piped whirlpool baths. Since the channels are completely inaccessible, you have no way to remove the residue build up and bacteria. Some manufacturers use check valves to prevent backfilling, but oily bath residue and scale deposits can cause check valves to fail. Our testing on one leading brand that advertises "a completely dry and sanitary system" visibly revealed that the automatic drying cycle does NOT completely dry the air channels. Testing by Rita Moyes, Ph.D. microbiologist, also found microbial contamination of the same brand of air tub (See discussion under question 8). Consumers should not be fooled into thinking that air tubs represent a safe alternative to conventional piped tubs. They DON'T.

What about fill-flush systems touted as the self-cleaning answer to bacterial contamination?

First, the term "self-cleaning" is badly misleading. No whirlpool bath cleans itself. These systems contain an inlet through which you must pour a product directly into the piping, fill the system with water and let it soak. The leading manufacturer recommends diluted bleach and advises the consumer to let the system soak "until it feels clean". Ask a fill-flush manufacturer for any scientific testing to back up its claims that its system prevents or removes bacterial contamination and let us know what they say. The relevant scientific evidence discussed above debunks the notion that fill-flush systems represent any serious answer to microbial contamination.

What about recirculating showers? Do they have contamination problems too?

These showers have vertically arranged jets connected to piping and a pump that recirculate wastewater from the shower floor onto the user. The same design characteristics that lead to contamination of piped whirlpool baths are common to recirculating showers--- residue buildup on the surfaces of inaccessible and uncleanable piping.

How are disease-causing organisms transmitted by a piped whirlpool bath?

A common mode is by aerosolization of the organism through bursting air bubbles which the bather and bystanders can then aspirate. Microbial transmission can also occur through water ingestion, entry through superhydrated skin follicles, cracked skin, open abrasions, or through the eyes, ears, and urinary tract.

Sickness and death from Legionnaires' Disease have been traced to spas, so what do experts say about the Legionella organism that has also been identified in piped whirlpool baths?

The following statements were taken from a verbatim transcript of a roundtable discussion concerning Legionnaires' Disease, at the CDC, on October 17, 1994:

Dr. Paul H. Edelstein, M.D.
Director, Clinical Microbiology Laboratory
University of Pennsylvania Medical Center
Philadelphia, PA

"If we take national and international figures, we know that somewhere between ... 3 to 30 percent of all home potable water systems contain this organism [Legionella]. In general, something in the range of 60 percent of most large buildings contain this somewhere within their water distribution system or the air-conditioning system. And so we're talking about an immense problem."

Dr. Christine Pasko-Kolva, Ph.D.
Environmental Group Leader
Perkin Elmer
Foster City, California

"I think it is very important to point out that the CDC has used that test [PCR] in other outbreaks in Colorado of a hot tub where the disinfectant level was at the appropriate concentration, yet there was still an outbreak." ."These protozoans [with Legionella engulfed in them] can insist, and once they insist they can be resistant to concentrations up to 50ppm of free chlorine ... after exposure to 50ppm ... amoeba cysts were able to exit and release the Legionella. So disinfection alone is not going to solve the problem. We do know that the infectious dose [of Legionella] is considerably low because it's an intracellular infection..."

Dr. Jean R. Joly
Directeur de la Recherche
Hopital du Saint-Sacrement
Quebec, Canada

"In a previous study it was shown that 100 percent of the water samples in southeastern United States were positive for Legionella."

Dr. Jon R. Geiger, Ph.D.
Group Leader, Microbiology
Olin Research Center
Cheshire, Connecticut

"I suspect that [air induction systems] may be a reservoir for all kinds of organisms. ... organics provide food and shelter for microorganisms, including possible pathogens. These organics also shield the microorganisms from the oxidizer and thus decrease the efficiency of sanitation.. Microorganisms in biofilms are difficult to kill, even with chlorine."

What assessment can one make about the health risk of using a piped whirlpool bath?

Consider what two experts say:

William J. Costerton, Ph.D., microbiologist
Director of the Center for Biofilm Engineering (CBE),
Montana State University

"The chance of infection during any given bath cannot be predicted with mathematical precision because contact with, or duration of, the bacteria is a random event depending on many variables. However, it is scientifically certain that all bathers are exposed to an environment conducive to infection and - if they are bathing in the typical nude fashion and having no device filtering the air they breathe - which, of course, is the usual procedures, they are taking no precaution against infection in an environment where they are surrounded by microscopic disease causing organisms and, unbeknownst to them, they should be taking precautions."

Michael Nicar, Ph.D., Epidemiologist
Board certified in clinical chemistry and pulmonary function testing
Credentialed in the field of human disease testing and research

"The relative risk for transmission of legionella via whirlpools, is significant (The Lancet 347:494, 1996), even for people standing next to the whirlpools (they did not even have to get in to the water). The drain and fill whirlpools make aerosols just like the hot tub models. Thus, the transmission of disease is the same between the drain and fill and the constant filled hot tub models."

"Physicians need to know that [whirlpool bathtubs] are a source of exposure to legionella bacteria. Otherwise, an erroneous diagnosis and incorrect choice of therapy may result." . . . "Delay of appropriate therapy can result in prolonged hospitalization, complications, and death . .

How do I test the water in my whirlpool bath to discover if it is contaminated?

Contact your local health department. You should be able to purchase special collection containers and receive instructions on the proper protocol for obtaining water samples. We recommend that you test for coliforms, pseudomonas aeruginosa, staph aureus and legionella. Ask your health department. You should also test the tap water supply to compare against the tub samples.