Increasing outbreaks of water illness prompt action

June 2005

Epidemiologists from across the nation are teaming up to develop a strategic plan to keep patients healthy as they head to the public pool this summer.

Health officials said they plan to issue a statement in the CDC’s Morbidity and Mortality Weekly Report that educates people about the importance of avoiding swimming while sick with waterborne illnesses, using proper hygiene techniques to avoid cross transmission, and improving surveillance for tracking these illnesses.

In response to a Council of State and Territorial Epidemiologists (CSTE) position statement, leaders from state, local and federal public health institutions, the health care community, the aquatics industry and nongovernmental groups recently gathered for the Recreational Water Illness Prevention Workshop to begin planning the first national, broad-based initiative to reduce and prevent illnesses associated with swimming pools, water parks and natural water sources, such as lakes, rivers and oceans.

“What we have seen over the past two decades is a steady climb in the number of outbreaks associated with recreational water, in particular, diarrheal disease outbreaks,” said Michael Beach, PhD, an epidemiologist in the division of parasitic diseases at the CDC and co-author of the CSTE position statement. “The emergence of recreational water illnesses has demanded a public health response, and we are pleased to see this unprecedented collaboration to address this growing threat.”

Surveillance data of recreational water outbreaks have indicated an increasing trend of gastrointestinal illnesses, mainly associated with contaminated facilities.

“Ingrained in the national psyche is the expectation of a healthy swimming experience. However, people need to keep in mind they share the water with everyone else in the pool who may spread illness, including kids in diapers,” added Beach, also the team leader of the Water and Environment Activity and a CSTE member.

Rising water illnesses

Pathogens, such as Cryptosporidium, Giardia, Shigella and Escherichia coli O157:H7 that are spread by swallowing contaminated water, cause recreational water illnesses.

While chlorine may kill a number of pathogens, some are not killed rapidly. Cryptosporidium can live for days in chlorinated water. Beach explained to Infectious Diseases in Children that Cryptosporidium accounts for nearly half of the disease outbreaks in chlorinated pools and swim parks, and biologically, this parasite is chlorine resistant.

According to the CDC’s surveillance data collected from 1999 to 2000, more than 2,500 people became ill during 65 water-related disease outbreaks from 23 states; however many cases go unreported. This represented the highest number of outbreaks and cases since reporting began in 1978, highlighting recreational water illnesses as a growing public health problem, according to a CDC statement.

Data are collected and reported as part of the national waterborne-disease outbreaks surveillance system maintained by the CDC, CSTE and the U.S. Environmental Protection Agency. This surveillance system is the primary source of data concerning the scope and effects of recreational water-related disease outbreaks in the United States.

“After a large-scale waterborne-disease outbreak in my state, I recognized the urgent need for epidemiologists from across the nation to team up with all the needed players in preventing illness from recreational water venues,” said Gail Hansen, DVM, MPH, author of the CSTE position paper and acting Kansas state epidemiologist.

Action taken

Hansen and Beach wrote a position statement addressed to the CSTE, suggesting a strategy to address this issue and decrease the prevalence of water illnesses must incorporate a “multifaceted and multidisciplinary approach.” Further recommendations incorporated in the position statement included the following:

• Improved health education activities to develop and disseminate educational messages concerning healthy swimming behaviors.
• Improved environmental health services to assure proper maintenance of chlorinated venues.
• Improved surveillance for recreational water illness outbreaks.
• New laboratory and epidemiologic research to answer critical questions.
• Additional resources for developing health swimming materials and programs.

CSTE members also recommended that partnerships between governmental and institutional groups be developed to identify a thorough strategic plan that can be implemented nationally and will effectively address this public health issue.

“Developing a national strategic plan to address the prevention and control of [recreational water illnesses] is both timely and necessary,” they concluded in their statement. “Implementing such a strategy may have a significant impact on public health.”

From these suggestions, the Recreational Water Illness Prevention Workshop forum was convened.

Workshop convenes

Nearly 100 participants attended the workshop, held in Atlanta, which called for establishing a national dialogue on the risks and solutions for ensuring healthy swimming.

“This is the first time we pulled together a national group from the aquatics sector, public health, academia and even within public health – the epidemiological side as well as environmental health side,” Beach said. “It is not something that is always done, but we absolutely see a need for a very seamless collaboration between those groups in the future to make this work.”

The first part of the two-part workshop focused on reducing illnesses associated with swimming pools and chlorinated swimming venues, where epidemiologists are seeing large increases in waterborne illnesses, Beach said.

Meeting attendees discussed the need to improve the tracking system of recreational water illness outbreaks across the nation and improve training for public health officials and pool staff. Disinfection efficacy trials and devices need to be conducted and created as well, he said.

Attendees also recommended the establishment of a national pool code model, so that state and local health departments can use the code to assist them in developing their own safety guidelines, Beach said.

The attendees also discussed the need for better public health education materials and communication to curb waterborne illnesses. He said the panel urged physicians to remind their patients presenting with waterborne illness to refrain from swimming until they are well again.

“We see this as being a multi-tiered effort that has to involve the public and also pool operators and public health workers as well,” Beach said. “We’re hoping to see raised awareness and action on all sides to move forward with this initiative.”

The next meeting will focus on suggestions and discussions preventing waterborne illnesses in lakes, rivers and other natural water sources, such as fresh and marine environment settings. This part of the meeting has not been scheduled at this point in time, Beach said.

The National Center for Environmental Health; Division of Emergency and Environmental Health Services; Environmental Health Services Branch; and the National Center for Infectious Diseases, Division of Parasitic Diseases, Healthy Swimming Program co-sponsored the workshop.

Swimming safety

Swimmers should ask how often the chlorine levels are checked and what the pool inspection scores from the public health department are, he suggested.

The CDC recommends swimmers forego swimming when they have diarrhea, which can contaminate the water and cause others to acquire the illness. In particular, parents of children in diapers are advised to keep their children out of the pool if they have diarrhea.

Practicing good hygiene by showering before and after swimming, washing hands after visiting the restroom or changing diapers and taking regular bathroom breaks are also recommended.

Swimmers should also refrain from getting pool water in their mouths. Less pool water swallowed reduces the risk of acquiring a waterborne illness, said Beach.

“We’d like people to transition from thinking of the pool as drinking water to communal bathing water,” he said. “We’re not saying don’t swim, but we’re saying swim responsibly and understand the process of improving the health of everyone in there.”

For more information:

• Information on the CDC’s “Healthy Swimming” can be found online at: www.cdc.gov/healthyswimming.
• Information on summer safety tips from the AAP can be found at: www.aap.org.

• Castor ML, Beach MJ. Reducing illness transmission from disinfected recreational water venues: swimming, diarrhea, and the emergence of a new public health concern. Pediatr Infect Dis J. 2004. 23:866-870.
• Yoder J, Blackburn B, Levy DA, et al. Surveillance for recreational water-associated outbreaks – United States, 2001-2002. MMWR Surveill Summ. 2004. 53:1-22.