Questions and Answers – Whirling Disease

Where has whirling disease been found?

Whirling disease was first confirmed in a sample from Johnson Lake in Banff National Park, Alberta. 

A collaborative surveillance plan has been developed and testing of samples collected by Parks Canada and by Alberta Environment and Parks is ongoing. Confirmed detections are being posted to the CFIA web site as updated information becomes available.

Additional detections of whirling disease from the ongoing sampling and testing do not mean the disease is spreading. Whirling disease may have been present for several years and the ongoing sampling will help determine the extent of the distribution and the most appropriate disease response.

How did whirling disease get introduced to Alberta?

It is not known how the parasite (Myxobolus cerebralis) which causes whirling disease was introduced to Alberta.

What fish are affected by whirling disease?

Whirling disease is an infectious disease of finfish that affects trout and salmon. Species found in Alberta that are susceptible to the disease are:

  • Oncorhynchus clarkii (cutthroat trout)
  • Oncorhynchus mykiss (rainbow trout)
  • Prosopium williamsoni (mountain whitefish)
  • Salmo trutta (brown trout)
  • Salvelinus confluentus (bull trout)
  • Salvelinus fontinalis (brook trout)

What is being done to control the spread of whirling disease in Alberta?

The Canadian Food Inspection Agency, Parks Canada and Alberta Environment and Parks are working closely together to determine the appropriate disease control response.

The Parks Canada web site provides information about whirling disease related restrictions or requirements in Banff National Park.

The Alberta Environment and Parks web site provides information about whirling disease related restrictions or requirements in the Province of Alberta.

The Canadian Food Inspection Agency will determine the need for any further disease declarations on the status of whirling disease when the complete results of this year’s surveillance plan sampling and testing have been received.

What can the public do to help control the spread of the disease?

People can spread whirling disease by moving any of the following:

  • infected live or dead finfish,
  • infected worms,
  • contaminated equipment, or
  • contaminated water, aquatic plants and soil or mud.

The public should avoid transporting any of these items from one body of water to another and clean equipment between uses.

More information on whirling disease precautions can be found on the CFIA web site.

Parks Canada will be providing guidance to park visitors on steps they can take to limit the spread of the disease.

Can the parasite that causes whirling disease be eliminated from Alberta?

There is no treatment for whirling disease in fish. The elimination of the parasite in wild finfish populations is not possible.

Is there a health risk for humans or pets?

No. The parasite that causes whirling disease does not affect humans or animals other than trout and salmon. There is no risk associated with swimming or eating fish caught from infected waters.

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