Swimmer’s Itch-2023 Update

Swimmer’s Itch (SI) has been in the area news a lot lately!

We understand that you may have questions or concerns. The good news, as of August 2023, we have had no guests report a case of swimmer’s itch on our beach. The less good news, there have been 192 cases reported on Crystal Lake as a whole (Merry, 2023).  Read on below to learn more about SI in Crystal. 

A beach and swimming concern: Swimmer’s Itch – An Overview

Swimmer’s itch is a skin condition caused when swimming larvae of several species of parasitic flatworms encounter human beings rather than their usual avian host, penetrate the skin and trigger an allergic reaction in many people. Scientifically known as schistosome cercarial dermatitis, it has been recognized in Michigan inland lakes since at least the 1920s, although only in recent years has it become a significant problem for recreation.

In response to increasing complaints on Crystal Lake, the Crystal Lake Watershed Association (CLWA) formed a Swimmer’s Itch committee in the summer of 2006. In 2009 concerned stakeholders formed the Crystal Lake Swimmer’s Itch Partnership, which now constitutes one of the standing committees of the CLWA.

In 2014, CLWA became one of 20 lake associations that formed a new coalition called Michigan Swimmer’s Itch Partnership (MISIP) By joining forces, the group has greatly expanded the expertise and resources now being directed at solving this complex problem.  It will help raise funds for scientific studies that will provide data regarding swimmer’s itch. This data enables organizations (such as Department of Natural Resources and Department of Environmental Quality) to receive funding to address swimmer’s itch. The formation and work of this partnership is a huge step in the quest to eradicate swimmer’s itch

In 2016, a small steering committee formed by the MISIP, developed a request for supplementary appropriations from the State of Michigan for a three-year pilot program that includes both research and practical control methods (such as merganser relocation). The State awarded $750K grant for the 3-year program.  The active support of the public will also be required to help raise the substantial funds needed for such a large-scale program, but experience has now clearly demonstrated that piecemeal efforts are not enough.

The CLWA website now has a new link that enables our Crystal Lake community to report cases of swimmer’s itch, and sightings of merganser broods and merganser nesting spots. This is part of CLWA’s swimmer’s itch control and research program, now under way for summer 2017, which the CLWA has contracted with Swimmer’s Itch Solutions LLC. (Curt Bankespoor, Adjunct professor, UM, Biological Station in coordination with his father, Dr. Harvey Blankespoor, retired professor emeritus of Biology, Hope College, both swimmer’s itch experts).

In 2022 on March 28, the Michigan Department of Natural Resources (DNR) notified the CLWA that all permits for the trapping and relocation of wildfowl in 2022 had been cancelled. This was due to the “highly pathogenic” outbreak of avian influenza (“bird flu”) in the state. 

In 2023, the relocation program has still not been allowed to resume. Due to this, there has been an increase in reported cases of SI in Crystal Lake. 

You will find the link to report cases or brood sightings on the home page of CLWA’s website: http://crystallakewatershed.org/

To find out more information about the Michigan Swimmers Itch Partnership (MISIP) go to this link: https://www.misip.org/


Preventing and Treating Swimmer’s Itch

  • Recently, some people have taken a proactive approach and have taken antihistamines prior to entering the water, such as Benedryl. 
  • Apply waterproof sunscreen or other products (see below) that may provide a barrier to the cercaria. Allow the product to dry before entering the water. 
  • For unprotected skin, while swimming run hand over the skin every 10 minutes or so. This may remove cercaria before they can penetrate. After swimming, towel off vigorously and shower with non-lake water.
  • If using sunscreen and also showering, reapply the product before re-entering the water.
  • If swimming for a long period of time, reapply the product according to the manufacturer’s directions.
  • Swim in deeper water when possible, as wind and waves may concentrate the cercaria in the shallows or close to the shore.
  • If you contract a severe case of Swimmer’s Itch, ask a pharmacist about anti-itch cremes or antihistamines.

Two sunscreens that are helpful…although they don’t completely prevent swimmers itch.

Bullfrog Waterproof Sunscreen with Deet or other insect repellents.

Rocky Mountain Waterproof Sunscreen (lotion or liquid)

  • Add 5 drops of citronella oil to an 8-ounce bottle (citronella is a natural insect repellant) shake and apply by hand or use a spray bottle. Do so carefully, adding too much citronella can stain clothing.
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