People who swam at Lake Johanna have reported getting swimmer's itch.
Ramsey County Parks and Recreation has received reports of swimmer's itch from a number of people who were recently at Arden Hills Beach Park, which is located within Tony Schmidt Regional Park.
"Anyone who swims or wades in the lake is advised to towel off or shower immediately after leaving the water," the county's website says.
Signs are posted at the beach.
The Centers for Disease Control and Prevention (CDC) says swimmer's itch, aka cercarial dermatitis, appears as a skin rash that's caused by an allergic reaction to some microscopic parasites that infect some birds and mammals. The parasites are released from infected snails and when they can't find a bird or a mammal, they'll burrow in a swimmer's skin, which causes the rash.
Anyone who swims or wades in the water could get swimmer's itch, however children are most often affected because they tend to play in the shallow water more than adults, and are less likely to towel dry themselves after getting out of the water.
Beachgoers who get swimmer's itch often don't need medical attention, but can do things like using corticosteroid and anti-itch creams, apply cool compresses and bath in Epsom salts, baking soda or oatmeal to help with symptoms. Scratching can make it worse.
If a lake is reported to have swimmer's itch, it won't always be a problem there. Specific factors are needed to keep the lifecycle of swimmer's itch going, the CDC explains. The larvae of the parasite live for about 24 hours after the snail releases them, but the infected snail can continue to produce the parasite for the rest of its life. For other snails to get it, a bird or mammal in the area must be infected to infect the snail.
Lake McCarrons beach still closed
The county did follow-up testing at the beach and found the levels are still high, so the beach will remain closed until results are within state guidelines for safe swimming.
Bacteria levels will be retested and an update on the beach reopening will be shared on June 16, the county says.
All other beaches the county operates and tests are within safe limits. You can find water quality results on the county's website here.
Several other Minnesota counties, including Anoka, Carver, Dakota, Hennepin, Washington and Wright, have beach water monitoring programs. The goal of the programs is to minimize the risk of people getting recreational water illnesses, most of which cause diarrhea.
You can find a list of counties and organizations in Minnesota that monitor and test beaches here.