Recreational Water Illnesses (RWIs) - Part 1 In their most recent summary the CDC reports that during 2003-2004 there were 62 Waterborne Disease Outbreaks (WBDOs) in recreational water. These occurred in 26 states and Guam, affected 2,698 persons, and resulted in 58 hospitalizations and one death. The reported number and severity of recreational water illness (RWIs) outbreaks continues to rise year after year. The CDC estimates the bather exposures at >368 million per year. Even when considering that at most ten percent of RWIs are reported the overall incidence rate of RWIs is quite low. Recreational water illnesses (RWIs) present a health threat to all users of aquatic venues because pathogens are prevalent in recreational water. RWIs are caused by microbial infections (e.g. bacteria, viruses, and parasites) as well as adverse chemical reactions (e. g. chloramines, accidental release of chlorine gas). RWIs may occur in treated venues (swimming pools, spas, spray pads, kiddy pools); natural untreated venues (lakes, natural beaches, rivers, streams); or man-made untreated venues (water parks using natural water). One way to classify RWIs is by the symptoms they cause. In treated venues the four major classes of RWIs are acute gastro-intestinal illness (AGI); dermal infections (rashes) and ear aches; respiratory infections; and adverse reactions to chemical exposure. For discussion here we will focus on the infections. There are many misperceptions regarding RWIs. In recent observations it has become quite clear that even experienced aquatic professionals fail to understand the occurrence patterns of RWIs in various venues. Two examples of this are Naegleria fowleri (the microbe that causes Primary Amebic Meningoencephalitis or PAM) and Schistosoma (the microbe that causes Cercarial Dermatitis or Swimmer’s Itch). These two parasites are restricted to fresh water (untreated venues). Naegleria has only rarely been linked to swimming pools but case studies strongly suggested exceptional conditions or other exposures. Yet, in the trade press and some training materials these organisms are listed as pathogens in swimming pools. Acute Gastro-Intestinal Illness (AGI) may be caused by bacteria (e.g., E coli O157:H7, Shigella), viruses (e.g., Norovirus, Echovirus), or parasites (e.g. Cryptosporidium, Giardia). The diarrhea and vomiting caused by AGIs is serious. Bathers affected by AGIs are more likely to seek medical attention than bathers affected by other RWIs. With the exception of Cryptosporidium, all of the microbes that cause AGIs can be readily controlled. How? Simply maintaining the chlorine concentration at 1.0 ppm or greater would have prevented at least 45% of the AGI outbreaks reported by the CDC. What is this telling us about how our public facilities are being operated when easily controlled microbes continue to cause illness? Bacterial rashes are also very common. Anecdotal evidence strongly suggests that rashes vastly outnumber AGIs. Nearly all bacterial rashes are caused by Pseudomonas aeruginosa. These rashes are most often minor and do not require medical treatment. Also, the incubation time can be quite variable, ranging from 2 up to 14 days. As a result the affected swimmer seldom seeks medical attention or even recognizes that the symptoms are linked to aquatic exposure. Many people simply don’t realize that improper treatment or under-treatment of their pools and spas poses a health risk. Several years ago in a previous job I was preparing a trade show presentation on RWIs and discussing rashes with co-workers. Our administrative assistant suddenly began to ask questions. Both she and her son had developed minor “red dots” after swimming in a friend’s pool. This had happened repeatedly during the summer. Upon examination of the pool we found a long history of under-treatment, and enough bacteria to make our seasoned bacteriology team squirm. Yet no one had recognized this as a case of improper pool treatment. What about public facilities? Think of hotel operations for a moment. It is quite common for hotel pools to be run by the front desk personnel on weekends. Few of the weekend and off-hours staff has any formal training in pools. Is it any wonder that rash outbreaks are very common at hotels on weekends? The third group of RWIs in treated venues is respiratory infections. The vast majority of reported cases are caused by Legionella pneumophilia. Like the bacteria that cause AGIs and rashes, Legionella is very easily control by either chlorine or bromine. The World Health Organization (WHO) has documented at least 50 outbreaks on cruise ships alone. There are at least three well-documented examples where untreated display spas at trade shows and big box stores have resulted in illnesses and deaths. This pattern is continuing. Recently one of my colleagues was shopping in a big box store that sells spas. There were three display spas full of water and running. All were untreated – and had been that way for days. It had never occurred to the department manager that these might be health threats. It is quite clear that the general public and many facility operators fail to understand that recreational water is not drinking water. RWIs can be prevented. Preventing RWIs will require both bather education program and improved operator training. The first step in RWI prevention is educating bathers. Nearly all AGIs can be prevented by not swallowing water. Where do these microbes come from? The microbes that cause AGIs are carried into the pool by infected bathers. A single fecal accident of either E coli O157:H7 or Cryptosporidium will release enough infective cells to contaminate every single swallow of water in a 225,000 gallon pool! Even after ill bathers “recover” they can still shed microbes for up to 14 days. It is not possible to prevent all fecal accidents but informing bathers not to swim for at least a week after having diarrhea will reduce AGIs. Dr. Michael Beach of the CDC points out that in the U.S. we use the word “swimmers” where in Europe the term is “bathers”. Most people would not intentionally swallow bath water. Perhaps a gentle reminder that pool water is really communal bath water could reduce the number of AGIs. While pool water should be clear like drinking water, pool water is not safe to drink. The CDC has prepared a number of posters for patrons on RWIs. These are available free of charge at www.cdc.gov/healthyswimming/. The Association of Pool and Spa Professionals (APSP) is developing a training module on recreational water illnesses. The Recreational Water Quality Committee of the APSP (the publisher of this newsletter) has been developing the module for use in various APSP classes. APSP training classes are taught nationwide by pool and spa professionals. The RWI module will be PowerPoint based and ready to use for any instructor. In addition, the module will include instructor notes. Leading the development of the module are Sam Fruia and Roy Vore. Sam is presently the Aquatic Administrator of the Brownsville Independent School District. Sam brings many years of coaching at the college and secondary level as well as facility management to the task. Roy is a senior microbiologist at DuPont and has many years of researching, writing, and speaking on the microbiology of pools and spas. The APSP RWI module will premier June 20 during the NEHA Atlantic City conference. You are invited to attend. Your impressions, suggestions, and recommendations are encouraged and will be incorporated. Roy Vore, Ph.D., Research Microbiologist Dr. Vore is a senior microbiologist in the Clean and Disinfect division of DuPont’s Chemical Solution Enterprise. Over the last fifteen years he has concentrated most of his work in the microbiology of swimming pools and spas. Dr. Vore has over 30 scholarly papers and presentations on the microbiology of swimming pools
© 2007 by The Association of Pool & Spa Professionals. All rights reserved. No part of this publication may be reproduced or transmitted without written permission. |
.jpg)
