Salmonid whirling disease

Scientific Name: Myxobolus cerebralis

Barry Nehring (photograph of infected brown trout)Copyright Info

Identification: This myxosporean is a microscopic parasite that causes salmonid whirling disease. The life cycle of this species occurs in two stages. It lives within intestinal cells of a small aquatic worm (Tubifex tubifex) and can be passed to trout and salmon when they consume infected worms. In infected fish, the disease can result in lesions in the skull, gills, and vertebrae, whirling behavior or tail-chasing, disruption of the central nervous system and balance, and sometimes death. This species is also known as Myxosoma cerebralis.

Size: This myxosporean parasite is microscopic.

Native Range: The native range of salmonid whirling disease is unknown. It is a common parasite of brown trout (Salmo trutta) in Europe, however, the infection generally is not associated with any symptoms.

Map Key
This map only depicts Great Lakes introductions.


Table 1. Great Lakes region nonindigenous occurrences, the earliest and latest observations in each state/province, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Myxobolus cerebralis are found here.

State/ProvinceYear of earliest observationYear of last observationTotal HUCs with observations†HUCs with observations†
Michigan197020036Au Gres-Rifle; Au Sable; Boardman-Charlevoix; Cheboygan; Lake Huron; Manistee
Minnesota197019701Lake Superior
New York197019881Lake Ontario
Ohio196819681Lake Erie
Wisconsin199819981St. Louis

Table last updated 9/30/2019

† Populations may not be currently present.

Means of Introduction: Salmonid whirling disease was probably introduced with non-native salmon that were stocked in the Great Lakes drainage system. It also could have arrived with transfers of rainbow trout (Oncorhynchus mykiss) from Europe back to North America prior to 1956.

Status: This parasitic infection may have been present in the Great Lakes system since the 1950s; however, it was first confirmed in 1968 at an Ohio aquaculture operation within the Lake Erie drainage. It has been found primarily at aquaculture facilities or in nearby waters within the Lake Ontario, Lake Erie, and Lake Michigan drainages. It has also been found in the wild in tributaries of Lakes Huron and Superior. In 1998, it was also discovered in Wyoming’s Yellowstone Lake.

Remarks: Prevention and control measures have increased in the Great Lakes region. It has been found that using concrete in aquaculture facilities can reduce the abundance of Tubifex worms, which limits myxosporeans’ ability to reproduce.

Lake trout (Salvelinus namaycush) is not susceptible to infection.

Author: Illinois-Indiana Sea Grant

Contributing Agencies:
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Revision Date: 9/25/2012

Citation for this information:
Illinois-Indiana Sea Grant, 2020, Salmonid whirling disease: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI,, Revision Date: 9/25/2012, Access Date: 1/28/2020

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.