Petition to rid Sand Hollow of swimmer’s itch begs the question: Can it be done?

Stock photo | St. George News

ST. GEORGE — A petition to remove the parasite responsible for swimmer’s itch from Sand Hollow State Park has been circulating through social media, prompting St. George News to determine if an eradication program is possible and if so, what that operation would look like.

A young boy exhibits signs of swimmer’s itch, Santa Clara, Utah, June 14, 2016 | Photo by Hollie Reina, St. George News

The petition to remove swimmer’s itch from Sand Hollow State Park was started by Nicolas Wagner on June 5, based on claims that the water in Sand Hollow Reservoir is “overwhelmed with a parasite known as Cercarial Dermatitis, aka Swimmer’s Itch.” The petition states that the water should be “treated for Swimmer’s Itch immediately.”

The Centers for Disease Control describes swimmer’s itch, or “cercaria,” as a skin rash caused by an allergic reaction to microscopic parasites carried by waterfowl, semi-aquatic mammals and snails.

The petition lists Utah State Parks and Recreation as the agency that should be responsible for the cleanup, but the department’s public information officer, Devan Chavez, told St. George News it is not possible to rid the water of swimmer’s itch “immediately,” adding that it doesn’t appear to be possible at all.

“We haven’t been made aware of any program that will remove swimmer’s itch from Sand Hollow or any other body of water in Utah,” Chavez said. “We have researched the issue but have yet to find anything that would be effective.”

Even if a solution were available, he said, there are multiple agencies that would need to “come to the table” to conduct impact studies on wildlife, agriculture and the food chain.

“But again,” he said, “we have not found a program that has any level of effectiveness.”

Why can’t we beat the itch?

The fundamental issues involved with implementing an eradication program have to do with the life cycle of the parasite, the effect a chemical additive may have on the environment and logistics.

First, the life cycle of the parasite that causes swimmer’s itch is a three-stage cycle, according to the Centers for Disease Control.

The larvae go through various stages of development, similar to a butterfly, starting with the adult flatworm that lives in the blood of infected birds. The female flatworm lays eggs that are released through the birds’ feces.

Once in the water, the eggs hatch and swim to the surface to optimally find a snail. If successful, the larvae enter the snail and continue to develop, producing thousands of new parasites that are then released into the water where they begin the search for a bird again, completing the cycle.

Photo of cercarial dermititis, parasite that causes swimmer’s itch | Photo courtesy of the Center for Disease Control, St. George News

However, if the larvae find a human first, they burrow into the skin of the swimmer and die off, since humans aren’t appropriate hosts. This is what causes the “itch,” a rash that appears as red, bite-like welts within several hours of leaving the water.

To address the problem, different eradication attempts have been tested in various states, including treating the snail population with an insecticide such as copper sulfate, which can be added to the water in early June and has had some effect in reducing the number of snails.

However, according to research conducted in Michigan, chemical treatments are only effective on the snail population present at the time of treatment, with no residual protection going forward. These chemicals also kill other plants and animals and may contaminate sediments, which can have long-range consequences that are still being studied.

The second issue relates to water, which is critical to the life cycle of the parasite.

Any chemical added to Sand Hollow to eradicate the snail population could have far reaching effects on the water supply, said park ranger and assistant manager Stephen Studebaker.

Anything that affects Sand Hollow can also have an affect on Quail Creek and the Virgin River, because the water flows between all three,” Studebaker said. “We have 3,500 acre feet of surface water at Sand Hollow, which is a huge area.”

Studebaker added that the water does not belong to the park; it is managed by the Washington County Conservancy District, an agency that diverts and stores more than 33 trillion gallons of surface water annually that is used to supply residents throughout the county.

Sand Hollow Reservoir is the largest of five reservoirs managed by the agency.

Quail Creek reservoir by the dam, Hurricane, Utah, May 11, 2018 | Photo by Mori Kessler, St. George News

Water from the Virgin River is diverted into the Quail Creek Reservoir, as well as Sand Hollow, a reservoir that sits on a natural sandstone aquifer that stores and holds 17 billion gallons of water,  Washington County Conservancy District’s general manager Ronald Thompson said.

That water is used to regulate levels between the two reservoirs before it is piped over to the Quail Creek Water Treatment Plant for processing and becomes part of the county’s water system.

Thompson told St. George News that copper sulfate is “occasionally” used at the water treatment facility to remove nonbeneficial algae during the treatment process but said it isn’t something they would put directly into the water at Sand Hollow to remove the snail population.

“We certainly wouldn’t treat the whole lake with copper sulfate because it would kill off the beneficial algae and would have little effect, if any, on the snail population,” he said, adding that the water ultimately serves as the drinking water for more than 150,000 residents.

More importantly, the bird population would have to be treated along with the snails, since both are necessary hosts for larvae development. This process involves capturing and administering a de-worming medication similar to the type used for cats and dogs.

Graphic showing life cycle of parasite that causes swimmer’s itch | Image courtesy of the Centers for Disease Control, St. George News

However, Thompson said, the bird population surrounding Sand Hollow is migratory, which means that even if it were possible to treat every bird, the population changes from one day to the next.

“With today’s technology, I just don’t see any way to successfully treat both the snail and bird population,” he said. “It’s just not possible.”

Utah is not alone in the battle against swimmer’s itch. Thirty states across the country have reported cases of the parasite, along with Canada and Europe, the CDC says.

One state that has conducted extensive testing and research on swimmer’s itch is Wisconsin, with its 15,000 lakes along thousands of miles of coastline.

Even so, Wisconsin has yet to find a viable option to control or eradicate swimmer’s itch, according to the Wisconsin Department of Natural Resources.

“There is no effective way to eliminate swimmer’s itch, and any attempts at control are ineffective because cercariae are capable of swimming or drifting long distances from non-treated areas,” the agency’s website said.

The good news?

This 2016 file photo shows a sign at the entrance to Sand Hollow State Park warning visitors that swimmer’s itch is active, Hurricane, Utah, June 23, 2016 | Photo by Cody Blowers, St. George News

Without an available option to eradicate the parasite, educating the visiting public is the focus at Sand Hollow State Park, Studebaker said, including posting signs when the parasite is active, one of which is located at the park’s entrance.

“We want the public to be informed, which allows them to take precautions and protect themselves and their families,” Studebaker said, “even if that means turning around and leaving.”

Studebaker said that so far this season, the actual number of cases compared to visitor numbers is “marginal.”

In addition, not everyone will be affected. Less than 7 percent of the population is affected by swimmer’s itch, and of those who are, a majority build an antibody after one reaction and do not experience symptoms again. Small children playing in shallow water are most susceptible, as they cycle between being wet and dry throughout the day, which increases the risk of being infected as the larvae tend to burrow once the swimmer leaves the water.

The level of discomfort varies with the person’s sensitivity and the extent of infestation, said David Heaton, Southwest Utah Public Health spokesperson, adding that while swimmer’s itch is neither dangerous nor contagious, it can be painful and very uncomfortable.

It’s one of those things that is a nuisance and uncomfortable but has no lasting effects,” Heaton said.

“Anytime there is heat, a large body of water with a lot of standing water, and snails and birds around, then we get a lesson on interacting with nature,” he added.

There are steps park visitors can take to minimize the risk of exposure, Studebaker said. The first is to avoid areas where plants or vegetation are growing and swim away from the shore whenever possible.

Areas where winds and wave currents tend to carry algae into the shallow water should also be avoided, as larvae can be carried as well.

Swimming during morning hours is also riskier, as cooler temperatures can increase the chance of coming into contact with the parasite.

Another suggestion is to rub down briskly with a towel immediately after leaving the water, which will remove or crush the larvae before they get a chance to penetrate the skin. If possible, showering right after swimming has also been shown to help.

Stapley Pharmacy carries a swimmer’s itch cream that can be used as a preventive measure and contains zinc oxide that serves as a protective barrier, according to a previous St. George News report.

Other swimmer’s itch remedies include the following:

  • Corticosteroid cream.
  • Cool compress to the affected area.
  • Bathe in Epson salts or baking soda.
  • Soak in colloidal oatmeal baths.
  • Apply baking soda paste to the rash.
  • Use an anti-itch lotion.

Swimmer’s itch updates and information can be found on the park’s Facebook page, and for additional safety tips and information go to the Sand Hollow State Park website.

Email: [email protected]

Twitter: @STGnews

Copyright St. George News, LLC, 2018, all rights reserved.


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  • Brian June 14, 2018 at 9:56 am

    Seriously, someone should do something. For the children. Immediately. If we could save just one child from swimmers itch it would all be worth it.

  • LocalTourist June 14, 2018 at 12:11 pm

    But only 7% of humans are affected by a non-fatal irritation. The article says other states have been unable to find a treatment that is successful in treating water to kill these parasites.
    Yeah, I get that it’s uncomfortable, but do we really want our kids swimming in a chemical soup? And if an effective treatment IS found, what about people that have a reaction to the chemicals put in the water? If we really want to be doing something “for the children”, maybe it should be avoidance of un-needed chemical exposure.

    • Brian June 14, 2018 at 2:41 pm

      My entire post was a sarcastic jab at snowflakes addicted to outrage and expecting the government to fix all of their problems. There is no way to “immediately” fix this, or really at all. The “for the children” and “do something” comments were a jab at those wanting to pass gun laws every time a shooting happens, even though the gun laws they say we should past often already exist or wouldn’t have prevented that shooting or almost any of the previous ones they reacted the same way to. There isn’t a viable solution to swimmers itch and other than the signs no money should be spent on it.

  • Blumpking June 14, 2018 at 2:22 pm

    They should allow waterfowl hunting at the lake to reduce the number of birds and discourage them from staying all winter. There are thousands of birds that are there through the winter. There is no reason to restrict hunting on the lake.

    • bikeandfish June 14, 2018 at 2:57 pm

      I don’t duck hunt that far south, is it off limits to the taking of waterfowl?

  • RadRabbit June 14, 2018 at 2:40 pm

    Non lethal and only affects a small percentage of the population, sounds like a waste of time and money.

  • Snarkles June 14, 2018 at 4:36 pm

    Oh yummy… and we have to drink these parasites. Just love our healthy water supply around here.

    • bikeandfish June 14, 2018 at 6:03 pm

      A fair amount of the human body is non-human, we are quite the ecosystem of microbes.

  • comments June 15, 2018 at 5:09 pm

    Some water is just too nasty to swim in. It’s amazing the amount of whining. Climate warming is a fact of life. Standing water is warming and the world will see more parasites like this in greater numbers as warming will continue. Find somewhere else to swim or deal with the discomfort of this parasite. It’s that simple.

  • youcandoit June 17, 2018 at 4:04 pm

    Or go to Stapley Pharmacy carries a swimmer’s itch cream that can be used as a preventive measure and contains zinc oxide that serves as a protective barrier. It’s a never ending cycle and to keep the costs of the parks fees and our water bill at least there’s preventative measures we can take.

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