Whirling Disease ( Myxobolus cerebralis )

1. Whirling Disease(Myxoboluscerebralis) Eric Stock Bio. 4800

2. History • Distribution • Species Infected • Life Cycle • Breeding Resistance Outline

3. European Origin • First recorded in Germany (1903) • Introduced to the United States (1950s) • Now Worldwide distribution Where did WD come from?

4. World Distribution

6. Currently no literature reporting WD in Canada • Approaching Albertan and British Columbian Borders Canada???

7. Species Susceptibility 0 = Resistant 1 = Partial Resistance 2 = Susceptible 3 = Highly Susceptible S = Susceptibility unclear

8. Native to Alberta Non-native Species • Bull Trout • Cutthroat Trout • Lake Trout • Rainbow Trout • Brook Trout (Eastern Canada) • 1903 • Brown Trout (Europe/Asia) • 1924 • Golden Trout (California) • 1959 Trout in Alberta

9. Primary Host = Trout/Salmon • Secondary Host = Tubifex Worms • TAM = infective stage • Spores can survive 20-30 years in mud • Juveniles less than 5 months = most susceptible Life Cycle

10. 1. Myxobolus cerebralis spore 2. Tubifex Worms 3. TAMs (Triactinomyxon) 4. Infected Trout

12. Parasite Transfer

13. Myxospores have been found in digestive tract of piscivorous birds • Avian vector is still unclear • Myxoboluscerebralisis very specific • Trout/salmon only • Fish eating mammals can’t be infected by the parasite • Eating fish will not infect YOU with WD Bird/Mammal Transfer?

14. Microarray analysis – examined expression changes in resistant and susceptible strains of rainbow trout after exposure to M. cerebralis • Hatchery rainbow trout from Germany (Hofer strain) • Acquired a degree of resistance to whirling disease • Higher than any domestic rainbow strains • Comparable to that of brown trout • Native to Europe (asymptomatic) to WD • Susceptible rainbow trout (US) Trout Lodge Breeding Resistance?

15. For both the resistant Hofer and susceptible Trout Lodge rainbow trout strains: • Response to infection linked with the interferon system • Metallothionein B was differentially expressed between the resistant and susceptible strains • A good candidate for future whirling disease resistance studies Results

16. The identified genes have allowed insight into trout’s immune response and resistance to whirling disease infection. • Additional studies crossed the resistant Hofer strain with a susceptible CRR strain (Colorado River rainbow trout ) • Resistance to whirling disease was inherited by offspring • Management: to re-establish trout in areas affected by WD Conclusion

17. Baerwald, M.R, Welsh, A.B, Hedrick, R.P, May. B. 2008. Discovery of genes implicated in whirling disease infection and resistance in rainbow trout using genome-wide expression profiling. BMC Genomics. 9: 1471- 1482 • Gilbert, M.A, Granath, W.O. 2003. Whirling Disease of Salmonid Fish: Life Cycle, Biology, and Disease. The Journal of Parasitology. 89: 658-667 • http://berryns.wordpress.com/2010/01/27/whirling-disease/ • http://whirlingdisease.montana.edu/default.asp • http://wildlife.state.co.us/Research/Aquatic/WhirlingDisease/WDResistantTroutBroodstock.htm • http://www.srd.alberta.ca/BiodiversityStewardship/WildSpecies/Fish/Default.aspx • http://www.thebowriver.com/whirling_disease_tu.htm • http://www.tu.org/whirling-disease References

18. Be Nice! Questions?