What is Marteilia refringens ?
Marteilia refringens is a protozoan that infects molluscs. Martelia refringens belongs to the phylum Paramyxea.
What species of molluscs can be infected by Marteilia refringens?
Each species of molluscs may have several common names, but only one common name is listed.
Species susceptible to Marteilia refringens that exist in the natural environment in Canada include:
- Mytilus edulis (Blue mussel)
- Ostrea edulis (European flat oyster)
Species susceptible to Marteilia refringens that do not exist in the natural environment in Canada include:
- Chamelea gallina (Striped venus clam)
- Mytilus galloprovincialis (Mediterranean mussel)
- Ostrea puelchana (Argentinean flat oyster)
- Ostrea angasi (Southern flat oyster)
- Ostrea chilensis (Chilean flat oyster)
- Solen marginatus (Razor clam)
Is Marteilia refringens a risk to human health?
No. The causal agent of Marteilia refringens is not a risk to human health.
What are the signs of Marteilia refringens ?
Marteilia refringens causes disease in molluscs. It is a cause of mortality in juvenile and adult molluscs.
- Overall mortality in oysters is 50% to 90%
- Overall mortality in mussels is 40% .
Affected molluscs may exhibit any of the following signs:
- behaviour
- gaping
- appearance
- poor body condition
- reduced growth rate
- small mantle
- pale digestive gland
- delayed gonadal development
Is Marteilia refringens found in Canada?
No. Marteilia refringens has not been found in Canada.
How is Marteilia refringens spread?
Marteilia refringens is spread between molluscs by
- contaminated water, and
- contaminated equipment.
People can spread Marteilia refringens by moving any of the following
- infected live or dead molluscs,
- contaminated water, and
- contaminated equipment.
How is Marteilia refringens diagnosed?
Diagnosis of an infection with Marteilia refringens requires identification of the parasite through laboratory tests. Not all infected molluscs show signs of disease.
How is Marteilia refringens treated?
There are no treatment options currently available for Marteilia refringens.
What measures can be taken to prevent the introduction and spread of Marteilia refringens?
If you frequently handle or work with molluscs, be aware of the clinical signs of Marteilia refringens.
Do not import live infected molluscs into Canada.
- An import permit is required from the Canadian Food Inspection Agency (CFIA) for certain species of molluscs as of December 2011.
- People bringing molluscs into Canada should check other federal, provincial, and/or territorial requirements before entering the country.
Do not introduce live molluscs from another country into the natural waters of Canada.
- People releasing molluscs into the natural waters or rearing facilities within Canada should check if federal or provincial and/or territorial permits are required.
If you frequently handle or work with molluscs, be aware of where Marteilia refringens occurs in your area.
- A federal, provincial and/or territorial permit or licence may be required to relocate molluscs within Canada.
Do not use molluscs that were bought in a grocery store as bait for catching fish or other aquatic animals.
Shells that are removed from molluscs or unwanted molluscs that you harvested or bought for your consumption should be disposed of in your municipal garbage.
The CFIA recommends that you do not visit Canadian aquaculture sites, zoos or aquariums for 14 days if you have travelled to another country and
- visited an aquaculture site, or
- had contact with wild molluscs.
Wash and disinfect the footwear you wore to the site or when you had contact with wild molluscs. Also wash your clothing thoroughly and dry it at a high temperature.
What is done to protect Canadian aquatic animals from Marteilia refringens?
Marteilia refringens is a reportable disease in Canada. This means that anyone who owns or works with aquatic animals, who knows of or suspects Marteilia refringens in their molluscs, is required by law to notify the CFIA.
If Marteilia refringens is found in Canada, the CFIA would control its spread by implementing disease response activities. These may include
- controlling the movements of infected animals that people own or work with
- humanely destroying infected animals
- cleaning and disinfecting
The control measures chosen would depend on the situation.
What do I do if I think molluscs that I am raising or keeping have Marteilia refringens?
If you suspect that the molluscs you are raising or keeping may have Marteilia refringens, you are required under the Health of Animals Act, to immediately notify the CFIA of your suspicion.
How do I get more information
For more information about reportable diseases, visit the Aquatic Animal Health page, contact your local CFIA Animal Health Office, or your CFIA Area office:
- Atlantic: 506-777-3939
- Quebec: 514-283-8888
- Ontario: 226-217-8555
- West: 587-230-2200