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Swimmer's Itch


What is swimmer’s itch (also called cercarial dermatitis)?

Is an allergic reaction that looks like a skin rash caused by certain microscopic parasites.  These parasites are released from snails into fresh and salt water (such as lakes, ponds, and oceans). The parasite prefers to live inside specific birds or mammals, such as a duck or snail.  But if the parasite comes into contact with a swimmer, it digs into the skin which causes the allergic reaction and rash. 

How does water become infested with the parasite?

Adult microscopic parasites live in the blood of animals such as ducks, geese, gulls, swans, and certain mammals such as muskrats and raccoons.

  1. The parasites make eggs that are passed in the feces of the birds or mammals.
  2. If the eggs land in or are washed into the water, the eggs hatch, releasing small, free-swimming microscopic larvae.
  3. These larvae swim in the water in search of a certain type of aquatic snail.If the larvae find one of these snails, they infect the snail.  There they multiply and undergo further development.
  4. Infected snails release a different type of microscopic larvae (or cercariae) into the water. This larval form then swims about looking for a suitable host (bird, muskrat) to continue the lifecycle.
  5. Although people are not the right hosts for these microscopic larvae, they will still dig into the swimmer’s skin.  This causes an allergic reaction and rash. Because these larvae cannot develop inside a person, they soon die. 

What are the signs and symptoms of swimmer’s itch?

  • Tingling, burning, or itching of the skin – within minutes to days after swimming.
  • Small reddish pimples – within 12 hours.
  • Small blisters – may develop.

Scratching the areas may result in secondary bacterial infections. Itching may last up to a week or more, but will gradually go away.

Do I need to see my health care provider for treatment?

Most cases of swimmer’s itch do not need medical attention. If you have a rash, you may try the following for relief:

      • Use corticosteroid cream.  
      • Apply cool compresses to the rash.    
      • Bathe in Epsom salts or baking soda.  
      • Soak in colloidal oatmeal baths.  
      • Apply baking soda paste to the rash (made by stirring water into baking soda until it reaches a paste-like consistency).  
      • Use an anti-itch lotion.

Try very hard not to scratch.  Scratching may cause the rash to become infected. If itching is severe, your health care provider may suggest prescription-strength lotions or creams to lessen your symptoms.

Can swimmer’s itch be spread from person-to-person?

You cannot get swimmer’s itch from another person.

Who is at risk for swimmer’s itch?  

      • Anyone who swims or wades in water where there is swimmers itch.  Larvae are more likely to be in shallow water by the shoreline.  
      • Children, who tend to swim, wade, and play in the shallow water.  They are also less likely to towel dry themselves when leaving the water.

What can be done to prevent swimmer’s itch?  

      • Do not swim in areas where swimmer’s itch is a known problem or where signs have been posted.           
      • Do not swim near or wade in marshy areas where snails are commonly found.  
      • Towel dry or shower right after leaving the water.  
      • Do not attract birds (e.g., by feeding them) to areas where people are swimming.


Fight the Bite

When enjoying time outdoors, it is important to be aware of ticks and take steps to protect yourself. You can take several steps to "Fight the Bite" and prevent getting ill from ticks. This includes using personal protection, removing ticks as soon as possible, and getting rid of ticks in your yard. Ticks are typically most active in Wisconsin from May to September, but it is still important to use caution year-round.

If you spend time outdoors often, download the Tick App(link is external), a free smartphone app from our partners at the Midwest Center of Excellence for Vector-Borne Disease (link is external) that allows people living in areas with a high risk of Lyme disease to report ticks, learn tick bite prevention tips, and help researchers understand ticks and the illnesses they spread.

Ticks may carry bacteria, viruses, or parasites that can also cause serious health problems. Lyme disease is the most common illness caused by ticks in the U.S.  Typical symptoms (signs) include fever, skin rash, headache, and being tired.  If you do not get treated, the infection can sometimes spread to joints, the heart, and the nervous system.

In the United States, West Nile virus is the most common disease spread by mosquitoes. West Nile virus can cause flu-like symptoms (signs) or cause serious illnesses that affect the brain, even resulting in coma and paralysis. In rare cases, it can even cause death.

Here are more detailed tips to prevent bites from mosquitoes and ticks:

  • Insect repellent, when used properly, can keep mosquitoes and ticks off your skin. Use repellents that contain DEET, picaridin, or oil of lemon eucalyptus, and adults should help apply repellents to children under 12.
  • Wear long-sleeve shirts, long pants, and socks to keep bugs off your skin.
  • Check for ticks daily after being outdoors, even in your own yard. Check all parts of your body carefully, including your armpits, scalp, and groin. Remove ticks immediately using fine-tipped tweezers.
  • Early morning, late afternoon, and early evening are peak biting times for mosquitoes that spread West Nile virus. It’s especially important to use repellent if you’re outdoors at these times.
  • Mosquitoes lay their eggs in water, even in small containers. Walk around the outside of your home at least once a week and empty any water that’s collected in toys, pet food and water bowls, birdbaths, buckets, and other objects. Check under bushes and other hard-to-see places. Get rid of old tires and other objects that can collect water.
  • Create a tick-safe zone around your home. For example: remove leaf litter and clear grasses and brush around your home and the edge of the lawn, and place mulch between lawns and wooded areas to keep ticks off the places you work and play the most.
  • Check for and repair holes in window and door screens.
  • Avoiding mosquitoes and ticks doesn’t mean that you have to stay inside, in front of the TV. Work and play outside, but remember to apply an effective repellent to exposed skin and clothing.

For more information, visit our Disease Control page:

To pick up a "Fight the Bite" kit, stop at the Public Health Department (330 Court Street, Eagle River). Kits will be provided throughout the county in the upcoming months.

Stay Safe during the Summer Weather 

Stay cool, hydrated, and informed during extreme heat this summer! Hot temperatures and humidity can be dangerous and even deadly.  Remember to stay cool, hydrated, and informed.

Follow these tips to stay safe during extreme heat:

  • Stay in air conditioning. When possible, stay in air conditioning on hot days. If you don’t have air conditioning head to a public buildings that have air conditioning. 
  • Check on loved ones. Be sure to check on older friends and neighbors who live alone and don’t have air conditioning.
  • Avoid the hottest part of the day. If you have to be outside, stick to the cooler morning and evening hours. Wear light, loose clothing and take frequent, air-conditioned breaks.
  • Beware of hot cars. Never leave a person or a pet in a parked car, even for a short time. On an 80-degree day, the temperature inside a car can reach 100 degrees in less than 10 minutes.
  • Stay hydrated. Drink plenty of water on hot days. Avoid alcohol and hot, heavy meals.
  • Stay informed. Watch your local weather forecasts so you can plan outdoor activities safely. Pay attention to any extreme heat alerts.
  • Keep your pets cool. Be sure to give your pets plenty of fresh, clean water. Make sure they have a shady place to get out of the sun, or bring them indoors. If you start feeling overheated, weak, dizzy, nauseated, or have muscle cramps, you could be experiencing heat illness. Move to air conditioning, drink water, get under a fan, and put cool washcloths on your neck or forehead. If your symptoms worsen or don’t improve, go to the emergency room or call 911.


Indoor Mold

The Key to Mold is Moisture Control

Tiny mold spores are all around us, both indoors and outdoors. Mold spores travel easily through the air and begin to grow indoors when moisture is present. There is no practical way to eliminate all mold and mold spores from the indoors, so the best way to control mold growth is to control indoor moisture. When indoor conditions are just right, mold spores can grow and become a problem. By taking important steps, you can prevent and control mold growth inside your home.

Mold spores need 3 things to grow:

  1. Moisture
  2. A nutrient source (i.e., wood, paper, or other materials)
  3. The right temperature

Of these three conditions, the most important to control is moisture. Indoor mold growth is really a sign that moisture is present. If indoor moisture is controlled, mold will not grow.

Fixing the Mold Problem

Since moisture is essential for mold growth, do all you can to quickly identify and fix any source causing too much indoor moisture. Common household problems that lead to indoor moisture issues include:

  • Roof leaks.
  • Leaking pipes or plumbing fixtures.
  • Condensation due to high indoor humidity.
  • Indoor flooding.

After all moisture and water problems have been fixed, clean the moldy area and keep the area dry.

If you cannot identify the moisture source, or if you are dealing with a large mold and water problem, consider a professional home inspection. Visit our Wisconsin Mold Contractor's page for a listing of indoor air consultants and mold remediation contractors.

Preventing Mold Growth

Important actions can be taken to prevent indoor mold from becoming a problem:

  • Keep indoor spaces well ventilated and dry. Air conditioners and dehumidifiers can help.
  • Keep indoor humidity levels below 50%.
  • Clean bathrooms often and keep surfaces dry. Run the bathroom ventilation fan during and after showers.
  • Promptly fix water leaks.
  • Clean up and dry your home fully and quickly (within 24-48 hours) after any flooding event.

Testing for Mold

The Wisconsin Department of Health Services does not recommend testing for mold because:

  • Federal standards or limits for airborne mold concentrations or mold spores do not exist.
  • Mold spores are everywhere around us, indoors and outdoors.
  • Mold testing can be expensive.

If you see or smell mold, it is present. In any situation, your approach should be to find the moisture source, fix it, and clean what you can.

Fact Sheets:

For more information, visit:

Tips for Food Safety in a Power Outage: