How many species of avian schistosomes can cause swimmers itch in Michigan?
Nobody knows the answer to this question. Based on previous work, it appears that there may be from 12-15 species in Michigan. This question is difficult to answer for several reasons. First. there are a large number of birds that potentially can serve as hosts for the adult worm. Second, the adult worms are so small and so difficult to remove from the blood vessels that few people have attempted to work out the classification scheme. A final difficulty is that for most species, the life cycles are not known. In other words, the snail intermediate and bird hosts for a specific species of schistosome remain an enigma.
