Whirling disease is caused by microscopic parasite of salmonid fish, including trout and salmon. The organism possesses a complex lifecycle that requires a salmonid fish and an aquatic-worm, Tubifex tubifex, as hosts.
Etiology: Myxobolus cerebralis
Disease Symptoms
- A marked “whirling” swimming behaviour may be observed as the parasite invades cartilage and damages the nervous system
- Skeletal deformities of the body or head
- the tail may be crooked
- head cartilage sunken to show a sloped head.
- Colour changes due to nerve compression, so that the tail may appear dark or even black.
- mass mortalities in fry
- increased rate of breathing
- darkening of the skin from the vent to the tail (‘blacktail’)
Mode of transmission
- infected live or dead salmonoids fish,
- infected worms,
- contaminated equipment, or
- contaminated water
Control measures
- Control of tubifex worms is best method to control this disease
- Rinse any mud and/or debris from equipment
- Quarantine check of fish stocks transferred are free from whirling disease
- Dispose of unused bait in the trash or on land rather than in the water.
- Never transfer live fish from one body of water to another.
- Do not use trout, salmon parts or mollusc as cut bait.
- Never discard fish entrails or skeletal parts in a body of water.
Reference
- https://www.in.gov/dnr/files/WHIRLING_DISEASE.pdf
- Biosecurity, Department of Agriculture, fisheries and forestry, government of Australia
Agriculturist Sujan 