Development of a DNA Test for Swimmer’s Itch at Flathead Lake in western Montana
Ryan Gustafson (email@example.com) Humboldt State University Research: Ryan Gustafson and Cheyenne Moore
Advisors: Elizabeth Rutledge and Antony Berthelote Team SPAW 2012
A DNA testing protocol has been developed and used to test for the parasite suspected to cause swimmer’s itch in Flathead Lake, western Montana. Trichobilharzia ocellata is a parasite of the family schistosomatidae that infects aquatic snails and waterfowl and is suspected to be the cause of swimmer’s itch at Flathead Lake. A series of parasite
identification and DNA testing techniques were implemented to determine the optimal protocol for investigating the suspected cause of swimmer’s itch at Flathead Lake. The most efficient method for identifying T.ocellata was determined to be by finding the parasite’s DNA among DNA extracted from the snail intermediate host. Four sets of
primers for the 18S small subunit ribosomal RNA gene and two sets of primers for a 396 base pair tandem repeat sequence of T. ocellata were used in the DNA test. The primers were used with snail DNA in PCR reactions, of which one set for the 18S gene showed amplification in one sample. The PCR product was sent for sequencing, the results of which indicate that the organism whose DNA was amplified is not T. ocellata. The sequence was determined to have the highest similarity (97‐98%) to the 18S gene of Rubenstrema exasperatum. However, considering that the 18S gene is highly conserved, the organism present in the sample is likely either a new species or one that has not had its 18S gene sequenced. The results of this research will be used to inform ongoing molecular studies of swimmer’s itch at Flathead Lake.