FREQUENTLY ASKED QUESTIONS ABOUT SWIMMER'S ITCH:
Parasites and Hosts

What is the life cycle of swimmer's itch causing parasites? Can cercariae be seen in the water? How many species of avian schistosomes can cause swimmer's itch in Michigan? Do all of these species of schistosomes use the same species of snails and birds as their hosts? What is the role of these birds and mammals in the life cycle of the parasites? How many hosts are there in the life cycle of the parasites that cause swimmer's itch? Do all snails carry the organisms that cause swimmer's itch? What is the relationship of snails to swimmer's itch? Are birds important to the organisms that cause swimmer's itch? How do you determine which birds are carrying the schistosomes that are causing swimmer's itch on a particular lake? Why should ducks, geese, and swans not be fed? How can you be sure that common mergansers play such an important role as bird hosts on so many lakes in Michigan? Can a relatively few common mergansers have an important swimmer's itch impact on a large recreational lake? Are Canada geese and mute swans important hosts for swimmer's itch? Is it possible to have swimmer's itch on a lake or pond even though we see no waterfowl during the summer? Is it legal to shoot common mergansers or other species of waterfowl that harbor parasites that cause swimmer's itch? Is there other information available on swimmer's itch?