Where M. cerebralis has become well-established, it has caused decline or even elimination of whole cohorts of fish. Impact in Europe
The impact of M. cerebralis in Europe is somewhat lessened because the species is endemic to this region, giving native fish stocks a degree of immunity. Rainbow trout, the most susceptible species to this parasite, are not native to Europe; successfully reproducing feral populations are rare, so few wild rainbow trout are young enough to be susceptible to infection. On the other hand, they are widely reared for restocking sport-fishing waters and for aquaculture, where this parasite has its greatest impact. Hatching and rearing methods designed to prevent infection of rainbow trout fry have proved successful in Europe. These techniques include hatching eggs in spore-free water and rearing fry to the "ossification" stage in tanks or raceways. These methods give particular attention to the quality of water sources to guard against spore introduction during water exchanges. Fry are moved to earthen ponds only once they are considered to be clinically resistant to the parasite, after skeletal ossification occurs. Impact in New Zealand
M. cerebralis was first found in New Zealand in 1971. The parasite has only been found in rivers in the South Island, away from the most important aquaculture sites. Additionally, salmonid species commercially aquacultured in New Zealand have low susceptibility to whirling disease, and the parasite has also not been shown to affect native salmonids. An important indirect effect of the parasites presence is quarantine restriction placed on exports of salmon products to Australia.
The Government of Alberta is currently sampling and testing fish in 6 different watersheds (Peace River, Athabasca, North Saskatchewan, Red Deer, Bow and Oldman) to see where the disease has spread. Initial sample fish were collected in 2016, and are currently being processed by the Government of Alberta and CFIA labs. Since testing began, it has been detected in the Upper Bow River, and in May 2017 it was confirmed that whirling disease had also been detected in the Oldman River Basin. The declaration does not mean that every susceptible finfish population within the Bow and Oldman River watersheds are infected with the disease.As a result of the new declaration, a domestic movement permit will be required from the CFIA for susceptible species and end uses identified in the Domestic Movement Control Program, the vector Tubifex tubifex, the disease causing agent Myxobolus cerebralis, and/or related things out of the infected and buffer areas of Alberta. Recreational and sport fishing, including fishing led by a professional guide, will not require a CFIA permit. Prevention and control
Some biologists have attempted to disarm triactinomyxon spores by making them fire prematurely. In the laboratory, only extreme acidity or basicity, moderate to high concentrations of salts, or electric current caused premature filament discharge; neurochemicals, cnidarian chemosensitizers, and trout mucus were ineffective, as were anesthetized or dead fish.