Comparative Trematode Biota of Healthy Waterbirds Harvested from

Comparative Trematode Biota of Healthy Waterbirds Harvested from Lake Winnibigoshish Minnesota Timothy Christopherson, James Mitchell, Connor Hutton, Miriah Linville, Okhumhekho Kassim, and Jacob Rachuy Graduate Supervisor: Tyler Achatz; Faculty Mentor: Dr. Robert Sorensen Minnesota State University, Mankato, Department of Biological Sciences Results Introduction Trematodes are animal parasites with complex life cycles that typically include an invertebrate intermediate-host and a vertebrate definitive-host (Roberts & Janovy, 2005). This study focused on the trematodes present in healthy waterbirds. In an effort to be efficient, parasites are often studied only when they have become a burden. While there is value in this type of research, there is also a wealth of information lost when neglecting to find what a normal parasitic load looks like in apparently healthy hosts. Previous studies involving waterbirds from Lake Winnibigoshish, MN, focused on the parasite community of sick or dead birds (Skillings, 2005). This study allows for a better understanding of the normal parasite burden of these host birds as well as providing some estimate of parasite population sizes that would fall below a threshold size associated with disease. Furthermore, this allows for insight into diet habits of these birds, which is a vital part to understanding the life histories of parasites. Fall Ring-necked duck Table. 1: The percent prevalence and mean intensity of intestinal trematodes in 13 fall and 7 spring collected ring-necked duck. Fall Spring Percent Mean Trematode species Prevalence Intensity Apatemon gracillis 100. 00 46. 70 71. 43 27. 60 Echinoparyphium aconiatum 46. 15 9. 00 42. 86 7. 33 Echinostoma chlorodopis 38. 46 5. 60 14. 29 16. 00 Echinostoma revolutum 61. 54 5. 50 14. 29 2. 50 Echinoparyphium recurvatum 7. 69 1. 00 0. 00 Maritrema obstipum 46. 15 65. 83 28. 57 26. 00 A. gracilis P. mediopora E. recurvatum M. obstipum E. aconiatum E. chlorodopis Unidentified strigeoid E. revolutum C. flabelliformis P. marilae S. pseudoglobulus Z. lunata Psilostomum marilae 15. 38 41. 50 0. 00 C. bushiensis Psilotrema mediopora 15. 38 30. 50 0. 00 N. attenuatus Sphaeridiotrema pseudoglobulus 15. 38 17. 50 42. 86 2. 33 Zygocotyle lunata 100. 00 2. 92 42. 86 3. 33 0. 00 14. 29 3. 00 Unidentified strigeoid Spring Ring-necked duck N. pacifera L. polyoon Echinostoma sp. Cotylurus sp. Fall American Coot Figure 2. Venn diagram depicting trematode species found among the different collections. Potentially pathogenic species are bolded. Table 2. The percent prevalence and mean of intestinal trematode species in 10 fall and 1 spring collected American coot. Fall Spring Percent Mean Trematode species Prevalence Intensity 30. 00 35. 00 0. 00 Cyathocotyle bushiensis Figure 1. Diagram depicting the typical trematode life cycle. Methods Parasite Collection: In fall 2012 and spring 2013, 13 & 7 ring-necked ducks and 10 & 1 American coot, respectively, were collected from Lake Winnibigoshish, MN. Intestines with ceca of birds were extracted and frozen on site. Intestines were thawed and split into ceca, small and large intestines. The small intestine was cut into 15 cm segments. All intestinal tissue was rinsed clean. All parasites found were fixed in formalin for morphological analysis or frozen for future genetic study. . Staining: Worms were dehydrated in ascending concentrations of ethanol, stained with Semichon’s acetocarmine, and mounted on slides with Kleermount. Identification: Morphological structures were used to identify species with primary and secondary dichotomous keys (Bray et al. , 2008; Mc. Donald, 1981). Leyogonimus polyoon 80. 00 825. 00 0. 00 Notocotylus attenuatus 10. 00 4. 00 0. 00 Notocotylus pacifera 70. 00 40. 00 Sphaeridiotrema pseudoglobulus 40. 00 34. 00 0. 00 Zygocotyle lunata 10. 00 2. 00 0. 00 Cotylurus sp. 10. 00 2. 00 0. 00 Echinostoma sp. 10. 00 6. 00 0. 00 Acknowledgements Thank you to Holly Bloom, Scott Malotka, Yuko Nakamura, Dr. Mauritz, Krista Wermerskirchen, the Department of Biological Sciences at MNSU, & the Minnesota Department of Natural Resources for their assistance in collecting and analyzing our specimens. For additional information regarding this study, please contact Tyler Achatz at tyler. achatz@mnsu. edu or Dr. Robert Sorensen at robert. sorensen@mnsu. edu. Conclusions 1. The large amounts of L. polyoon, a trematode associated with bird die-offs, in healthy American coot is unusual. It is possible the hosts were recently infected and had not had time to develop symptoms yet. Two of the American coot studied showed internal signs of disease associated with L. polyoon, however, neither of these birds had external signs of disease. Other American coot had large loads of L. polyoon, but had no signs of disease. 2. The ring-necked ducks appear to harbor a wider range of intestinal helminthes. This range may be due to diet differences between bird species, intestinal environment or competition caused by L. polyoon. 3. Spring birds held fewer species and number of trematodes. This is likely due to the over-wintering location of the birds which may lack the appropriate environment for trematode life cycles. References Bray, R. (2008). Keys to the Trematoda - volume 3. CABI Publishing. Roberts, L. , & Janovy, J. (2005). Gerald D. Schmidt & Larry S. Roberts' foundations of parasitology (7 th ed. ). Boston: Mc. Graw-Hill. Mc. Donald, M. Edwin. (1981). Key to trematodes reported in waterfowl. Washington, D. C. : U. S. Dept. of the Interior, Fish and Wildlife Service. Skillings, Derek (2005). Search for the causative organism of waterfowl deaths at Lake Onalaska, Journal of Undergraduate Research at Minnesota State University, Mankato: 5(20)