Archive for the ‘Pools’ Category

Preparing for the Summer of Zika Virus

Friday, April 1st, 2016

Fig. 1. U.S. map showing 1) Ae. aegypti potential abundance for Jan/July (colored circles), 2) approximate maximum known range of Ae. aegypti (shaded regions) and Ae. albopictus (gray dashed lines), and 3) monthly average number arrivals to the U.S. by air and land from countries on the CDC Zika travel advisory. Additional details can be found in the text. Figure reproduced with permission of PLOS Currents Outbreaks.


Are you curious about your risk of contracting Zika virus this summer?  The figure above is from a brand new study1 on the projected spread of the Aedes aegypti mosquito, the main Zika virus “vector”2. Based on meteorological models, mosquito-breeding patterns, air travel and socioeconomic status, the study compares the January, 2016 abundance of the mosquito (upper hemisphere of each circle) in each geographical location with its projected abundance this July (lower hemisphere of each circle).  The area of each circle is proportional to the estimated monthly average arrivals of people to the US from countries on the Centers for Disease Control and Prevention (CDC) travel advisory list.

The researchers project the greatest concentration of the Aedes aegypti mosquito in the US this summer will be throughout the Gulf Coast states and along the eastern seaboard as far north as New York City, a destination of many arrivals from countries on the CDC Zika travel advisory.  In fact, the circle for New York City is approximately the same size as the one for Miami.

Zika Virus to Date

As of early spring, 2016, virtually all of the known Zika virus infections in the US have been acquired during travel to other countries. Many Zika-infected individuals travelled to Latin America and the Caribbean, where there are Zika virus pandemics.  In Florida, where I am an Environmental Administrator in the Florida Department of Health (FL DOH), we have documented 67 cases of travel-related Zika virus.  Texas has had 27 confirmed cases, including one believed to have been sexually transmitted.  With the northern migration of the Aedes aegypti mosquito carrier this summer, however, Zika virus could soon be transmitted in the US.

The FL DOH and other state and county health departments in Zika virus-vulnerable areas are in full response mode.  States of emergency have been declared in 12 Florida counties,3 and Florida has a mosquito control district operating in every county. Having worked at the FL DOH for over 30 years, I know we will harness the lessons learned in the past fighting other mosquito borne illnesses, such as Eastern Equine Encephalitis and Dengue Fever.  We will inevitably learn a few new tricks as we turn our attention to Zika.  We already have a robust communication plan around this public health threat.

What Florida is Doing to Fight Zika

Daily Zika Updates:  Each day at 2 pm EDT, the Florida DOH issues an online Zika update and press release, identifying new Zika cases, making recommendations, and providing links to additional information.

Tips for Residents:  The Florida DOH website “encourages Florida residents and visitors to protect themselves from all mosquito borne illnesses by draining standing water; covering their skin with repellent and clothing; and covering windows with screens.”  See our “Drain and Cover” web page for more information, including keeping pool chemistry maintained.  Appropriate pH and chlorine levels will help avoid swimming pools becoming breeding grounds for mosquitoes.

Tips for Travelers:  The Florida DOH website advises travelers to tropical and sub-tropical regions can protect themselves from Zika virus and other mosquito borne illnesses by using appropriate insect repellent, covering skin with long-sleeved shirts and long pants, and keeping mosquitoes out of hotel rooms by choosing a hotel with air conditioning or window screens or sleeping under a mosquito bed net.  Our website notes that pregnant women should consider postponing travel to areas of Zika virus transmission.

Basic Information on Zika virus:  Zika is transmitted through the bite of infected Aedes aegypti mosquitoes. Perinatal (mother to child in the weeks just before or just after birth) and sexual transmission have also been reported.

 As summer approaches, stay tuned to public health communications on Zika virus so that you can make decisions and take actions to help protect your family.


Bob G. Vincent is an Environmental Administrator in the Florida Department of Health. He manages Department of Health programs for Healthy Marine Beaches, Safe Drinking Water, Water Well Surveillance and Public Pools and Bathing Places.

Click here to download this article.

1 Monaghan AJ, Morin CW, Steinhoff DF, Wilhelmi O, Hayden M, Quattrochi DA, Reiskind M, Lloyd AL, Smith K, Schmidt CA, Scalf PE, Ernst K. “On the Seasonal Occurrence and Abundance of the Zika Virus Vector Mosquito Aedes Aegypti in the Contiguous United States,” PLOS Currents Outbreaks. 2016 Mar 16 . Edition 1. doi: 10.1371/currents.outbreaks.50dfc7f46798675fc63e7d7da563da76.

2Disease vectors, according to the World Health Organization, are “living organisms that can transmit infectious diseases between humans or from animals to humans.”  In addition to Zika virus, the Aedes aegypti is a vector for Chikungunya, Dengue fever, Rift Valley fever and Yellow fever.

3 Alachua, Brevard, Broward, Hillsborough, Lee, Miami-Dade, Orange, Osceola, Polk, Santa Rosa, Seminole and St. Johns Counties

Zika Virus: On the Move

Friday, February 5th, 2016

Zika virus is being actively transmitted by mosquitoes in Brazil, Paraguay, Bolivia, Ecuador, Columbia, Venezuela, Curacao, Guyana, French Guyana, Suriname, Mexico, Guatemala, Honduras, El Salvador, Nicaragua, Panama, Haiti, Dominican Republic, US Virgin Islands, St. Martin, Puerto Rico, Guadeloupe, Martinique and Barbados.

The Zika virus, a flavivirus1, is spreading “explosively” through several Latin American and Caribbean countries, according to the World Health Organization (WHO), prompting that group to declare an international health emergency which, according to the BBC “…means research and aid will be fast-tracked to tackle the infection.”  The virus is transmitted through the bite of the Aedes aegypti and Aedes albopictus mosquitoes, the same mosquito that, according to WHO, transmits dengue, chikungunya and yellow fever.  The virus was identified in the Zika forest of Uganda in 1947 in rhesus monkeys, then in humans in Uganda and the United Republic of Tanzania in 1952.  Recently, Zika virus was reported in Chile in 2014, followed by Brazil in 2015.  Currently the virus is being transmitted actively in over 20 countries.  As of yet, there is no reported active transmission of the virus in the US, but some travelers have returned to the US infected with Zika virus.  As CDC notes, “Any travelers visiting or returning to parts of the United States with established populations of Aedes aegypti or Aedes albopictus mosquitoes could initiate local virus transmission.”

Health Effects of Zika Virus

The Zika virus is spread mainly by the Aedes Aegypti mosquito. Mosquitoes breed in stagnant water and, unchlorinated pools and water storage tanks.

The US Centers for Disease Control and Prevention (CDC) notes that one in every five people infected with Zika virus will become sick for up to one week with fever, rash, joint pain and “nonpurulent” conjunctivitis (“pink eye” without the pus).  That means that 80 percent of people infected have no symptoms, but are carriers of the virus.

Zika virus testing is not widely available.  It is performed only at the CDC Arbovirus Diagnostic Laboratory and a few state health departments, according to CDC.  Test results can be misleading (false positive) if the individual in question was previously infected with another flavivirus, such as dengue, or has been vaccinated against yellow fever or Japanese encephalitis.

Pregnant women who are infected with the virus can pass it on to their unborn children.  There is a question, based on preliminary data from countries such as Brazil , as to whether those children may be at risk for microcephaly, a condition of abnormally small heads that is associated with underdevelopment of the brain.  Studies are needed to clarify whether there is an association between Zika virus infection and microcephaly and Guillain-Barre syndrome.

Pregnant women or women who may become pregnant should not travel to outbreak areas.  Meanwhile, the virus continues to spread at an alarming rate, and there is neither a vaccine for its prevention nor anti-viral medications for treating symptoms.   Research on Zika virus is just beginning, and new information will likely be revealed in the weeks and months ahead.

Maintain Chlorine Levels in Swimming Pools and Water Storage Tanks to Help Prevent Mosquito Breeding

Mosquitoes breed in standing water, not just the puddles and pools remaining following a rainstorm, but any still water that is not intentionally made inhospitable to breeding. For that reason, it is important to maintain appropriate chlorine levels in swimming pools and water storage tanks.

Swimming pool water should be chlorinated in the range of 1-4 parts per million (ppm) and stored drinking water chlorine levels should be kept above 1 ppm free chlorine. This measure not only helps prevent mosquito-breeding, but also helps prevent a host of waterborne illnesses that can be contracted from bacteria and other pathogens in water.

Preventing Zika Virus TransmissionStrategies to prevent mosquito breeding and human exposure to mosquitoes are our best bet for preventing the virus transmission.  These include:

  • Eliminating standing water in flower pots, buckets, barrels, old tires, untreated kiddie pools and other containers that can serve as breeding grounds for mosquitoes.
  • Ensuring good drainage of water around homes.
  • Maintaining a chlorine residual of about 1 mg/l in stored treated drinking water; drinking water storage is common in developing countries that lack central water distribution.
  • Making sure backyard pools are appropriately chlorinated as mosquitoes will not breed in chlorinated water.
  • Inspecting and repairing window and door screens.
  • Applying an insect repellent to exposed skin and/or clothing when spending time outdoors. The Aedes aegypti mosquito bites during daytime hours. Products containing DEET, picaridin, IR3535, and some products containing oil of lemon eucalyptus and para-menthane-diol may provide long-lasting protection; follow label directions for use.2
  • Applying insect repellent to skin after applying sunscreen, if sunscreen is to be used.
  • When you are outdoors, air movement around your body (from fans or natural breezes) disrupts mosquito flight and reduces your risk of being bitten.


Ralph Morris, MD, MPH, is a Physician and Preventive Medicine and Public Health official living in Bemidji, MN.

Fred M. Reiff, P.E., is a retired official from both the U.S. Public Health Service and the Pan American Health Organization, and lives in the Reno, Nevada area.
Click here to download this article.

1 Flaviviruses, according to CDC, are a family of positive, single-stranded, enveloped RNA viruses that cause widespread illness and death.  They are found primarily in ticks and mosquitoes and can occasionally infect humans.  Flaviviruses include Yellow Fever, Dengue Fever, Japanese encephalitis, West Nile viruses and Zika virus.

2 For more information on insect repellents and their effectiveness, please see

This Winter, Use Your Senses around Your Indoor Pool

Friday, January 22nd, 2016

A “Natatorium” is an indoor swimming pool

Is swimming your exercise of choice this winter? According to the US Census Bureau, swimming is America’s fourth most popular recreational activity after (1) walking,
(2) exercising with equipment and (3) camping. Unless you’re a polar bear, indoor pools help make swimming a year-round option, and swimming brings health benefits galore. But how do you know if you are swimming in a healthy indoor pool?

The Water Quality & Health Council asks swimmers to be sensible around the pool. Translation: In addition to making smart decisions on safety, such as diving only in designated areas and not running on the deck, swimmers can use their five senses to:

  1. See: You should be able to see clearly through the water to the pool floor stripes.
  2. Smell: Indoor pools should not have a strong, irritating chemical odor. This is a common problem in indoor pools, however, stemming from (a) poor air ventilation and/or (b) improper pool chemistry. See the text box below.
  3. Touch: The tiles around the pool water line should feel clean, not slimy.
  4. Hear: You may hear the sound of the pool filter at work.
  5. Taste: Avoid tasting the water; swallowing even a small amount of water could make you sick. Remind children not to drink pool water!
Indoor Air Quality
Irritating chemical compounds called chloramines can build up in the air and water of an indoor swimming pool, causing respiratory and other health effects that degrade the indoor swimming experience. Chloramines are the chemical products of (a) chlorine from pool sanitizers and (b) ammonia-based substances (e.g., sweat, urine, oils) from the bodies of swimmers. Pool facility operators can minimize swimmers’ exposure to chloramines by maintaining proper pool chemistry, and encouraging swimmers to shower before entering the pool and refrain from “peeing in the pool.”

Another way that pool operators can reduce chloramines in and around the pool is by adequately managing air exchange in the indoor pool environment. Chloramines are volatile and fill the air over the swimming pool after they form in the water. Air currents that sweep away chloramines also help remove chloramines from the water. Good air exchange with outside air also helps reduce the humidity of the indoor air, helping to reduce mold and mildew.

Another way to ensure that you are swimming in a healthy pool is to use pool test strips to check that the pH and “free chlorine” level are within acceptable bounds. These strips are available in hardware and pool supply stores, and free from the Water Quality & Health Council each summer.

For more information on indoor pool air quality, please see the US Centers for Disease Control and Prevention website.

Bob G. Vincent is an Environmental Administrator in the Florida Department of Health. He manages Department of Health programs for Healthy Marine Beaches, Safe Drinking Water, Water Well Surveillance and Public Pools and Bathing Places.

Click here to download this article.

Responding to Dengue Fever

Friday, October 9th, 2015
Responding to Dengue Fever

The female Aedes aegypti mosquito is the “vector” that transmits dengue fever from person to person.Image reprinted from the US Centers for Disease Control and Prevention website.

In the wake of recent monsoons and flooding, mosquito-borne dengue fever is once again on the rise in the Asia Pacific Region.  According to the US Centers for Disease Control and Prevention (CDC), worldwide, dengue fever cases number over 50 million annually.  The World Health Organization (WHO) estimates1 that globally 2.5 billion people, over one-third of the world’s population, live in areas that put them at risk for the viral disease, and about 70 percent of them (1.8 billion) live in the Asia Pacific Region.

Dengue is rare in the continental US, but endemic in Puerto Rico, where the CDC maintains a center of expertise and a diagnostic laboratory in its San Juan Dengue Branch.  It is also endemic to the Caribbean, Mexico and Central America.  According to the Gates Foundation website, dengue fever incidence has increased 30-fold worldwide since the 1960s.  Increasing urbanization and global travel contribute to ongoing outbreaks globally.

Dengue Fever Symptoms

Dengue fever symptoms range from mild fever to incapacitating high fever, with severe headache, pain behind the eyes, muscle and joint pain and rash, according to the World Health Organization.  Symptoms appear 3 -14 days after the infective bite.   The CDC advises patients to go immediately to an emergency room or closest health care provider if any of the following warning symptoms appear:

  • Severe abdominal pain or persistent vomiting
  • Red spots or patches on the skin
  • Bleeding from nose or gums
  • Vomiting blood
  • Black, tarry stools (feces, excrement)
  • Drowsiness or irritability
  • Pale, cold, or clammy skin
  • Difficulty breathing

Dengue hemorrhagic fever is a severe, potentially lethal form of the disease that generally requires hospitalization.  Children usually have a much milder form of dengue fever than adults, but those who survive the disease have a much greater chance of dengue hemorrhagic fever if they are subsequently infected as adults with a different serotype of the virus.

Avoiding Mosquitoes to Avoid Dengue Fever

Dengue fever is spread by the bite of infected Aedes aegypti mosquitoes, which are endemic to the southeast sector of the US among other world regions.  Humans are the reservoir of the disease, and there are at least four dengue viruses.  A person bitten by an infected mosquito may or may not develop symptoms.  That person cannot transmit the illness directly to others, but if a mosquito bites that person after he/she becomes infected, that mosquito can spread dengue fever to others through ongoing biting. According to the CDC, the Aedes aegypti bites primarily during the day. This species is most active for approximately two hours after sunrise and several hours before sunset, but it can bite at night in well-lit areas.

There is neither a vaccine for dengue fever nor specific antiviral medicines to treat the illness.  Preventing dengue is a matter of avoiding mosquitoes and their bites. Strategies include:

  • Eliminate standing water in flower pots, buckets, barrels, old tires, untreated kiddie pools and other containers that can serve as breeding grounds for mosquitoes.
  • Ensure good drainage of water around homes.
  • Maintain a chlorine residual of about 1 mg/l in stored treated drinking water; drinking water storage is common in developing countries that lack central water distribution.
  • Make sure backyard pools are appropriately chlorinated as mosquitoes will not breed in chlorinated water.
  • Inspect and repair window and door screens.
  • Apply an insect repellent to exposed skin and/or clothing when spending time outdoors. Products containing DEET, picaridin, IR3535, and some products containing oil of lemon eucalyptus and para-menthane-diol may provide long-lasting protectionfollow label directions for use.2
  • Apply insect repellent to skin after applying sunscreen, if sunscreen is to be used.
  • When you are outdoors, air movement around your body (from fans or natural breezes) disrupts mosquito flight and reduces your risk of being bitten.

The Indian Government is Activated

The Indian Express reports the current Dengue Fever outbreak is the worst one in five years, and notes other diseases with similar symptoms are also on the rise, including typhoid and B. coli.  The newspaper reports government inspectors go house-to-house in New Delhi in search of standing water, for even a few milliliters of clear water can become the breeding grounds of mosquitoes. Steep fines are imposed on residents who harbor standing water.  Fumigation is practiced in some areas.  Children are advised to wear full-sleeved shirts.

Government doctors have been told they will be on the job with no leave until the outbreak subsides and the number of hospital beds has been increased.

A High-opportunity Target

As flooding in the Asia Pacific region subsides, dengue cases are expected to decline.  Nevertheless, the disease remains one of the “most widespread vector-borne viral infections in the world,” according to the WHO.3  The Gates Foundation calls dengue fever a “high-opportunity target” because several potential vaccines are in development. The foundation supports efforts to develop a dengue vaccine, which it estimates could prevent more than 500,000 hospitalizations and 3,000 deaths annually, most of these among children (see press release).

An effective vaccine against dengue fever is the response we would most like to see to this global scourge.

Click here to download this article.

For more information on dengue fever and the Aedes aegypti mosquito, please see this CDC resource.

Ralph Morris, MD, MPH, is a Physician and Preventive Medicine and Public Health official living in Bemidji, MN.

1See: World Health Organization, Regional Office for South-East Asia, Asia-Pacific Dengue Strategic Plan (2008-2015)

2For more information on insect repellents and their effectiveness, please see

3WHO.  Dengue hemorrhagic fever:   Diagnosis, treatment, prevention and control. Geneva. World Health Organization, (1997): 12-23

How to Drain a Residential Swimming Pool

Friday, September 18th, 2015

Summer’s nearly over and many backyard swimming pool owners will soon undertake their annual “pool draining ritual.” Draining the water helps prevent damage to pools in geographic areas subject to freeze-thaw cycles. This article provides information to help you drain your pool responsibly.

What’s the Big Deal?

It’s easy enough to fill your pool with water, so why is draining it a big deal? First, all summer your swimming pool water has been treated with chemicals to help keep it safe for you and your family. Chlorine-based sanitizers, for example, probably were used to help destroy waterborne pathogens that can cause diarrhea, swimmer’s ear and skin infections. These germs can enter the pool on the bodies of swimmers and in animal feces. Chlorinated pools also prevent your backyard pool from becoming a mosquito breeding ground; mosquitoes potentially spread diseases like West Nile virus. But the same low levels of chlorine-based sanitizer that help keep pool water safe for your swimmers can be harmful to fish and wildlife.
The second reason to stop and think before you pull the plug is to consider the sheer volume of water and where it will flow to or pond outside the pool. Will it flow onto your neighbor’s property? Will it pond in a depression? Are you planning to drain your pool directly into a sewer? Better find out what type of sewers are nearby. A storm sewer will channel your pool water directly into a natural stream or other body of water with no treatment. Only sanitary sewers channel wastewater flow to treatment facilities.

This storm sewer in Montgomery County, Maryland bears a sign that indicates water flowing into it drains into Rock Creek, a tributary of the Potomac River, and warns residents not to pollute.

Tips to the Drainers

  • Consult your local municipal Department of Environment Quality for specific guidelines or codes. The US Environmental Protect Agency (EPA) website highlights, for example, Montgomery County, Maryland’s Department of Environmental Protection guidelines.
  • According to an Oregon Department of Environmental Quality Fact Sheet, if possible, swimming pool water should be sent to a treatment plant via a sanitary sewer. This is most important for large (especially community) pools, and happens automatically when in-ground pools are built with a drain that goes to a sanitary sewer.
  • If drainage to a sanitary sewer is not possible, water may be allowed to evaporate to a lower level for the winter, if desired, or disposed of on the ground or used to irrigate your property. Water should be released, however, only after the pool owner stops adding chlorine or other treatment chemicals, or shuts off the chlorination system and holds the water in the pool for at least one week while chlorine levels drop.
  • When disposing of pool water on the property or using it to irrigate your property, do so in a manner that water will not flow off your property or into a stream or storm sewer.
  • When disposing of pool water on your property, do so in a manner that water will not pond for a prolonged period, resulting in nuisances such as odors and insect breeding conditions.
  • If discharge to the ground will result in flow to a stream ditch or storm sewer, increase the holding time of water in the pool with no added chlorination to at least two weeks to allow chlorine to dissipate.
  • Use a pool test kit to measure the chlorine level of the pool water prior to draining to ensure there is no detectable chlorine level (for example, the Washington, DC Department of Energy and Environment website indicates less than 0.1 mg/l free chlorine is acceptable). A longer holding period may be necessary if free chlorine levels are above 0.1 mg/l.

Happy Swimming Pool Winterizing!

Chris Wiant, M.P.H., Ph.D., is president and CEO of the Caring for Colorado Foundation. He is also chair of the Water Quality & Health Council.

Click here to download this article.

What to do about Bird (and Other) Droppings in the Swimming Pool

Friday, August 7th, 2015

There’s nothing like a swim in an outdoor pool in beautiful summer weather. As the open air is the domain of nature’s flying creatures, however, the occasional splat of bird droppings in the pool is to be expected. What, if anything, needs to be done about bird droppings in the pool?

According to the US Centers for Disease Control and Prevention (CDC) website, many germs that might be present in bird droppings can infect humans, although few, if any, outbreaks have been associated with bird droppings. Duck and goose droppings are highlighted by CDC as potentially containing E. coli, Salmonella, Campylobacter or Cryptosporidium. Fortunately, in a well-maintained pool most pathogens in bird droppings are killed by chlorine within minutes, according to CDC. Cryptosporidium, a microscopic parasite surrounded by a tough chlorine-resistant outer shell, can be removed by a well-maintained pool filtration system.

Addressing Bird (and Other Types) of Droppings in the Pool

CDC recommends pool managers and backyard pool owners treat bird droppings in the pool in the same way that they would respond to finding formed human feces in the pool. The goal is to remove the waste material, if possible, and disinfect the water by taking the following steps:

  • Close the pool to swimmers.
  • Put on disposable gloves.
  • Remove the waste material using a net or bucket. Do not vacuum the waste from the pool.
  • Clean off any debris or dirt from the item used to remove the waste.
  • Disinfect the item used to remove the waste by immersing it in the pool during the 30-minute disinfection time described below.
  • Remove and dispose of gloves.
  • Wash your hands thoroughly with soap and water immediately.
  • Raise the free chlorine concentration to, or maintain it at, 2 parts per million (ppm); maintain the pH level at 7.5 or less; keep the temperature at 77°F (25°C) or higher. The free chlorine and pH should remain at these levels for 30 minutes.
  • Confirm that the filtration system is operating properly.

How to Discourage Birds around the Pool

CDC provides the following tips for discouraging birds (not the duck and geese varieties) from frequenting the pool area:

  • Remove plants that produce edible nuts, fruits, and berries.
  • Remove bird feeders.
  • Trim or remove trees and shrubs to limit branches hanging around or over the pool that can be used by roosting birds.

To discourage ducks and geese:

  • Do not keep domestic ducks and geese in the pool area to decrease the likelihood of wild ducks and geese becoming attracted to the area.
  • Do not feed ducks or geese.
  • Ducks and geese eat grass. If possible, reduce the area of grass lawns around the pool or install barriers that control movement between the pool and grass lawns, such as fences, grid wires and hedges. Noise makers, goose repellents and trained dogs can also be used to discourage non-migratory or resident geese from becoming a nuisance.

Happy swimming! For more information on addressing animals and pools, please see this CDC website. For further information on waste products in pools, please see the CDC’s Fecal Incident Response Recommendations for Pool Staff, linked from this CDC web page.

Bob G. Vincent is an Environmental Administrator in the Florida Department of Health. He manages Department of Health programs for Healthy Marine Beaches, Safe Drinking Water, Water Well Surveillance and Public Pools and Bathing Places.

To download a copy of this article, click here.

Avoiding Norovirus at the Lake

Friday, June 26th, 2015

 Norovirus, the notorious “stomach bug,” can spread like wildfire  through homes, schools, healthcare facilities and cruise ships.  According to a recent report by the US Centers for Disease Control and Prevention (CDC), the virus also can be spread among swimmers in natural water bodies. In July, 2014, 70 people became ill with norovirus after swimming in Oregon’s Blue Lake, on the outskirts of Portland.  More than half of these were children between four and ten years old.  A CDC investigation found those who swam in the lake over the course of one weekend were more than twice as likely to develop vomiting or diarrhea as those who visited the lake but did not go in the water.  The outbreak was the subject of public communication during CDC’s 2015 Healthy and Safe Swimming Week1.

Anatomy of an Aqueous Outbreak

Last summer’s norovirus outbreak in Oregon probably started after a sick swimmer had diarrhea or vomited in the lake, dispersing numerous norovirus particles into the water.  Other swimmers then inadvertently swallowed water contaminated with norovirus. Unlike treated recreational water venues such as pools and water parks, natural waters do not contain disinfectants that can destroy norovirus and other pathogens.  Even in properly treated venues, however, disinfectants take time to work, so one should never assume pool water is completely germ-free.

Norovirus is the second-leading cause of waterborne illness outbreaks in untreated recreational waters. The leading cause is the bacterium Shigella.

Blue Lake was closed to swimmers for ten days to prevent further norovirus cases, but CDC noted its investigation highlighted a need for guidance for public officials to help them determine when to reopen recreational water venues following outbreaks.  We agree this should be a priority, especially given the fact, as CDC notes, that there is evidence norovirus can survive in water for several months, and even years.

Healthy and Safe Swimming

The CDC report also noted a need for communication tools to inform the public about the risks associated with swimming in untreated recreational water venues, including the ocean, lakes, ponds and rivers.  Many of the same tips for avoiding waterborne illness in treated venues, such as swimming pools, apply to lakes and ponds, including:

  • Don’t swim if you have diarrhea or have been vomiting.
  • Don’t urinate or defecate in the water.
  • Don’t swallow lake water.
  • Take children on frequent bathroom breaks.
  • Check diapers, and change them in a bathroom or diaper-changing area–to keep germs away from the water.

We submit the following additional tips for healthy swimming in untreated recreational water venues:

  • Do not swim in waters posted as “no swimming” zones.
  • Avoid swimming after a heavy rain to avoid exposure to sewage from overflowing sewage treatment systems or contaminated runoff.
  • Limit the amount of water going up your nose to reduce your chance of contracting a rare but deadly Naegleria fowleri amoeba infection. These infections have been documented in people who swim or dive in warm fresh water venues.
  • Check with local health or environmental officials if you are unsure about swimming in a natural body of water.
  • Shower after swimming.

For more information on swimming in natural water bodies, see the CDC website, Oceans, Lakes & Rivers and the linked US Environmental Protection Agency’s brochure, “Before You Go to the Beach” at:

Click here to download this article.

1 Formerly known as “Recreational Water Illness and Injury Prevention Week,” this year the annual observance occurred May 18-24, 2015.

Swimming Pools Myths Busted over the Airwaves

Friday, June 19th, 2015

We recently completed our annual Healthy Pools “radio media tour” of 23 radio stations across the US, during which we dispelled common swimming pool myths and promoted tips on staying healthy in the pool this summer.  Here are some highlights from the tour:

MythThere is a dye that is used to identify swimmers who pee covertly in the pool.

There is no dye in pool water to indicate the presence of pee (pockets of warm “water” may be an immediate, but fleeting give-away).  Rather, swimmers are on the “honor system” when it comes to getting out of the pool to use the bathroom.  We highly recommend doing this (see below).

Myth:  Swimmer’s eyes turn red when there is too much chlorine in the pool.

Too much chlorine in the pool would be irritating to the eyes, but chlorine itself is not the common cause of swimmer “red eye.”  Swimmers’ eyes redden from irritants–known as chloramines–produced when urine and sweat in the pool combine chemically with chlorine pool disinfectant.  To quote Dr. Tom Lachocki of the National Swimming Pool Foundation, “Swimmers’ eyes are the real color indicator that someone might have peed in a pool.”

For a healthy experience in the pool: shower before swimming to remove sweat, dirt, cosmetics and trace fecal matter (yes, we all carry some, so please shower thoroughly).  The pre-swim shower and frequent bathroom breaks can go a long way toward letting chlorine carry out its critical role of killing germs in the pool instead of having to bind with the various impurities swimmers add to pool water.

Use Your Senses and Use Pool Test Strips

Over the course of our interviews, we repeated these simple tips on using your senses to evaluate the “health” of a swimming pool:

Sight:  Make sure you can see clearly through the water to the floor of the pool.

Sound:  If you are near the mechanical room, you should be able to hear the pool pumps operating to circulate the pool water.   For larger pools, pumps might not be as audible.  In that case, you should be able to feel water being pumped into the pool in various locations, especially near the bottom of the pool.

Smell:  A properly maintained pool should have NO HARSH CHEMICAL odor.

Touch:  Tiles on the sides of the pools should feel smooth and clean, NOT SLIMEY.

Taste:  Avoid getting water in your mouth and swallowing it.

Finally, pool test strips are a simple tool swimmers can use to check the pH and free chlorine level of pool water. Order a free pool test kit at

Happy Swimming in Healthy Pools.  Over and out!

 Click here to download this article.

Chris Wiant, M.P.H., Ph.D., is president and CEO of the Caring for Colorado Foundation. He is also chair of the Water Quality & Health Council. Ralph Morris, MD, MPH, is a Physician and Preventive Medicine and Public Health official living in Bemidji, MN.

Saluting Our Fallen Heroes with Swimming Lessons for Children

Friday, June 12th, 2015

Jerod M. Leob 

Swimming is a skill that can provide endless enjoyment, help keep you fit, and even save your life.  As a group of public health and safety professionals, we have been strong proponents of healthy swimming for nearly 25 years.  We believe all children should learn to swim, and that is why we are so impressed with the Angels of America’s Fallen project (AoAF), brought to our attention by the National Swimming Pool Foundation.

The non-profit AoAF project helps provide “wish list” activities, like swimming lessons, to the children of fallen soldiers and first responders.  The project recognizes and strives to fill the gap in the lives of children of fallen heroes.  We are especially proud that a donation will be made to AoAF by the American Chemistry Council’s Chlorine Chemistry Division in our honor as a tribute to one of our own fallen, Jerod M. Loeb, PhD.

Jerod was an active member of the Water Quality & Health Council for over 20 years, and a treasured friend.  His life was not stopped short by an enemy bullet on the battlefield or in trying to save a life, but by cancer on October 9, 2013.  Jerod was a tireless soldier for public health and safety.  In his professional capacity at The Joint Commission, he worked to improve hospital performance and patient safety.  This role took on new meaning as Jerod transitioned from health care administrator to health care recipient during his final illness.  Jerod was also a volunteer first responder.  A graduate of the Buffalo Grove Citizen’s Fire Academy, he was a fully trained member of the Buffalo Grove Community Emergency Response Team.  In 2005, Jerod was appointed Commissioner of Fire and Police for the municipality of Buffalo Grove.

We miss our friend terribly, both professionally and personally.  We respectfully place Jerod in the ranks of America’s fallen heroes, and honor his memory with the very real tribute of children of other fallen heroes becoming proficient swimmers.

Angels of America’s Fallen is a 501(c)(3) public charity headquartered in Colorado Springs, Colorado.

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Safe Fun in the Kiddie Pool

Friday, May 29th, 2015

A Word to the Wise: If you plan to leave the end of a garden hose submerged in the pool, remember that not all states require backflow preventers on hoses. Without a backflow preventer, it is possible that tainted pool water will flow back into the drinking water system when the hose is turned off. 

Kiddie pools can bring hours of delight to young children on a hot summer day.  But unlike larger pools, small plastic and inflatable kiddie pools are normally not equipped with water filters or treated with chemicals that remove germs and balance pH.  Add to this the fact that hygiene is not a strong suit of the kiddie pool set, and a few helpful tips are in order for safe fun in the kiddie pool:

  • Fill the pool with fresh water before each use:  Without the benefit of chemical treatment, kiddie pools must be refilled with fresh tap water before each use.  When my children were small, I would fill the pool with water early in the morning and let it warm up for a few hours before letting the children go in.  Naturally, adult supervision is needed around the water-filled pool.
  • Bathe children before they enter the pool: This may sound counterintuitive, but without bathing children first, the risk of their contaminating the pool with pathogens rises.  Without getting too graphic, the diaper and underpants area are the source of most of the pathogens that can make kids sick.  Change diapers as needed, and keep in mind that swim diapers or swim pants are not leak-proof.  If your little swimmer is potty trained, build in some bathroom breaks to avoid “accidents.”
  • Sick children should not be in the pool with other children: A child who is experiencing diarrhea or vomiting must not be allowed in the pool with other children. If a child becomes sick in the kiddie pool, a quick exit of everyone from the pool is in order.  The pool must be emptied of water, cleaned and disinfected before being used again (see the next tip). 

Do You Bathe Your Children Together?

The Centers for Disease Control and Prevention website notes children from the same family or household who are often bathed together are unlikely to be at increased risk of spreading diarrheal illness to each other when using the same inflatable or plastic pool. Allowing larger numbers of children from different families to use these pools, however, is likely to increase the risk of spreading diarrheal illnesses.

  • Clean and disinfect the kiddie pool after each use: Drain or empty the pool after each use. Leaving the pool full overnight is unsafe, both because it is a potential drowning risk and a potential waterborne disease risk.  (Did I mention there are no disinfectants in the water?)  The Centers for Disease Control and Prevention (CDC) recommends cleaning the pool after it has been used, and once dry, leaving it in the sun for at least four hours.  The ultraviolet rays of the sun can be effective at destroying pathogens.  Alternatively, if manufacturer’s directions agree, the kiddie pool interior can be cleaned and then disinfected with a simple chlorine bleach solution.  For example, the “How to Clean Stuff” website1 recommends using a solution of one part bleach to five parts water. Rinse the pool well after this treatment. 
  • Don’t drink the kiddie pool water: Discourage children from drinking pool water from kiddie pools or from any pool, for that matter.  After all, we know from a 2009 Water Quality & Health Council survey that approximately one in five adults admit to having peed in the pool–a habit that might have started in the kiddie pool.  Distracting young children with a “sippy cup” of a favorite beverage may help, but don’t be surprised if the beverage ends up poured over somebody’s head! 

Here’s to a happy, healthy and safe fun in the kiddie pool.

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 Barbara M. Soule, R.N. MPA, CIC, FSHEA is an Infection Preventionist and a member of the Water Quality & Health Council.

1 Although the “How to Clean Stuff” website recommends draining kiddie pools only once per week, I strongly recommend draining the pool immediately after use.