Whirling Disease ( Myxobolus cerebralis )

Whirling DiseaseWhirling Disease(Myxobolus cerebralis)(Myxobolus cerebralis)

Eric StockBio. 4800

OutlineOutline

History

Distribution

Species Infected

Life Cycle

Breeding Resistance

Where did WD come from?Where did WD come from?

European Origin

First recorded in Germany (1903)

Introduced to the United States (1950s)

Now Worldwide distribution

World DistributionWorld Distribution

Canada???Canada???

Currently no literature reporting WD in Canada

Approaching Albertan and British Columbian Borders

Species Species SusceptibilitySusceptibility

0 = Resistant

1 = Partial Resistance

2 = Susceptible

3 = Highly Susceptible

S = Susceptibility unclear

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 Trout in AlbertaAlberta

Life CycleLife Cycle 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

1. Myxobolus cerebralis spore 2. Tubifex Worms

3. TAMs (Triactinomyxon) 4. Infected Trout

Parasite TransferParasite Transfer

Bird/Mammal Transfer?Bird/Mammal Transfer?

Myxospores have been found in digestive tract of piscivorous birds

Avian vector is still unclear

Myxobolus cerebralis is very specificTrout/salmon only

Fish eating mammals can’t be infected by the parasite

Eating fish will not infect YOU with WD

Breeding Resistance?Breeding Resistance? 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

ResultsResultsFor 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

ConclusionConclusion

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

ReferencesReferences 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

Questions?Questions?

Be Nice!