Each summer as lake water temperatures rise, some swimmers begin to get the itch - swimmer's itch, that is.

A few reports have been made in the Park Rapids area already but there are no "hot spots," said Edie Evarts, Assistant Area Fisheries Supervisor for the Department of Natural Resources in Park Rapids.

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According to the Department of Natural Resources, only 30-40 percent of people are sensitive to swimmer's itch. Much like poison ivy, the more times you come in contact with the organism that carries swimmer's itch, the more likely the chances are that you will get it.

The life stage that causes swimmer's itch is called a "cercaria" which is an immature stage of a blood fluke common in waterfowl, according to the DNR. The cercaria only lives for a day or so and typically inhabits the upper few inches of water, which increases its chances of coming into contact with a duck, its host. This behavior makes it easy for them to be moved around the lake, and tends to concentrate their numbers along the shoreline.

The DNR offers the following tips to minimize the likelihood of getting swimmer's itch:

-Do not encourage waterfowl to hang around beaches. They can carry the adult form of the organism, so it is better if they aren't hanging around public beaches. The organism that causes swimmer's itch has a complicated life history. However, an important fact to consider is that the critter starts out in the intestinal lining of waterfowl, mostly ducks. Stop feeding any geese or ducks near the dock.

-After swimming, dry off immediately. The organism needs water to live, when water starts evaporating off the skin, it burrows in to survive. Toweling off immediately after swimming helps avoid this scenario.

-If possible, swim from a raft or boat farther out in the water. The organism drifts to shallow water near the shoreline, so it's best to avoid wading or playing in shallow water.

-Be sure to keep beaches clean of weeds and other debris that washes ashore. Snails carry the organism too, so if there are weeds or other debris near shore, there's a possibility that there are snails around also.

If a person comes into contact with swimmer's itch, symptoms begin within 24 hours. Some symptoms include the tingling, burning or itching of the skin, small reddish pimples and small blisters.

It is not contagious however, and the symptoms can last for a few days up to several weeks.

If the itching becomes severe, a pharmacist may be able to recommend some creams or lotions to help.

If these strategies don't work, there is an option of getting a permit from the DNR to use copper sulfate to kill the snails that are an intermediate host of the parasite.

Evarts said people can get a permit at the Park Rapids Fisheries Office. Call 732-4153.

Infected snails release the life stage (cercaria) that actually causes swimmer's itch. The copper sulfate will only kill the snails present at the time of application; any snails that enter the area afterward will not be affected.

The relief provided may be temporary and more than one treatment may be required.