Swimmer's Itch

 

It finally felt like summer this week!  It's that time of year again when swimmer's itch can be a problem.  Today I will talk about what swimmers itch is, and how to avoid it.

 

Swimmer's itch is when you leave the lake after swimming and about an hour later some itchy red spots appear on your body.  It can itch for a week or so and feel uncomfortable.  Once you have had swimmer's itch, your skin may be more sensitive to it next time.

 

Swimmer's itch is caused by a tiny parasite that enters your skin from the water.  That sounds repulsive, but the parasite doesn't do any harm to humans besides causing itchy red bumps.  Most of the parasite species that cause swimmer's itch use aquatic snails as intermediate hosts for the larval parasite stages and bird hosts for the adult parasite.  So how do humans fit into this picture?  When the larval parasite leaves the snail, it then needs to enter a bird to survive.  We get caught in the middle when the parasite enters our skin instead of the birds.  Some common bird hosts include common mergansers, mallards, swans, and red-winged blackbirds.

 

Swimmer's itch is usually most prevalent in shallow downwind areas of lakes.  In Detroit Lakes, it seems to be a problem in mid-June through mid-July.   The presence of swimmer's itch doesn't really have anything do to with water quality or pollution on a lake.  You just need the right kind of snails and the right kind of birds.

 

So how can you prevent getting swimmers itch?  First, avoid feeding water birds by your lake home.  Feeding ducks, geese and swans can propagate swimmer's itch in the area where birds are being fed.  It also makes the birds dependent on humans for survival and makes them a nuisance.

 

Second, avoid swimming or standing for long periods in shallow water, and when you leave the water rinse off, towel off, and remove your wet swimsuit.  Children are commonly affected by swimmer's itch because they play in shallow water and tend to be in the water more than adults.  If you swim off a boat or raft in a deeper area of the lake, you will probably have less of a chance of getting swimmer's itch.

 

If you think you have swimmer's itch, you can go to the pharmacy and ask the pharmacist for a recommendation.  Usually a topical cream can reduce swelling and itching.

 

Until next week, enjoy the lakes!

 

Moriya Rufer is the Lakes Monitoring Program Coordinator for RMB Environmental Laboratories in Detroit Lakes, 218-846-1465, lakes.rmbel@eot.com.