This response varies from species to species.In T. tubifex, the release of triactinomyxon spores from the intestinal wall damages the worms mucosa; this may happen thousands of times in a single worm, and is believed to impair nutrient absorption. Spores are released from the worm almost exclusively when the temperature is between 10 °C and 15 °C, so fish in warmer or cooler waters are less likely to be infected, and infection rates vary seasonally. Susceptibility
Fish size, age, concentration of triactinomyxon spores, and water temperature all affect infection rates in fish, as does the species of the fish in question. The disease has the most impact on fish less than five months old because their skeletons have not ossified. This makes young fish more susceptible to deformities and provides M. cerebralis more cartilage on which to feed. In one study of seven species of many strains, brook trout and rainbow trout (except one strain) were far more heavily affected by M. cerebralis after two hours of exposure than other species were, while bull trout, Chinook salmon, brown trout, and Arctic grayling were least severely affected. While brown trout may harbor the parasite, they typically do not show any symptoms, and this species may have been M. cerebralis original host. This lack of symptoms in brown trout meant that the parasite was only discovered after nonnative rainbow trouts were introduced in Europe.
Unfortunately, this treatment is considered unsuitable for wild trout populations, and no drug treatment has ever been shown to be effective in the studies required for United States Food and Drug Administration approval.Recreational and sports fishers can help to prevent the spread of the parasite by not transporting fish from one body of water to another, not disposing of fish bones or entrails in any body of water, and ensuring boots and shoes are clean before moving between different bodies of water. Federal, state, provincial, and local regulations on the use of bait should be followed. See also
Ceratomyxa shasta – another pathogenic myxosporean parasite of salmonids
Infectious salmon anemia (ISA) – a viral infection of Atlantic salmon
Kudoa thyrsites – a myxosporean parasite of many species, which causes fish tissues to liquefy on death
Tetracapsuloides bryosalmonae – the enigmatic myxosporean which causes "proliferative kidney disease" in salmonids
Salmonid susceptibility to whirling disease

Notes
External links

Report of the World Trade Organization on Australian restrictions on salmon imports
The Whirling Disease Initiative
Whirling disease maps and data
Species Profile- Whirling Disease (Myxobolus cerebralis), National Invasive Species Information Center, United States National Agricultural Library, lists general information and resources for whirling disease
Whirling Disease - Yellowstone National Park (U.S. National Park Service)
Whirling Disease - Stop Aquatic Hitchhikers
Whirling disease - Utah Division of Wildlife Resources
Colorado Parks & Wildlife - Whirling Disease and Colorados Trout
What is Whirling Disease? - North Central Regional Aquaculture Center - Mohamed Faisal - Donald Garling
Whirling disease | Alberta.ca