Chronic wasting disease - What to expect if your animals may be infected
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Notice to industry - 2019-03-15 - Updates to the federal management of chronic wasting disease in farmed cervids
Chronic wasting disease (CWD) is a fatal disease of cervids, such as deer, elk and moose. CWD is not known to affect human health, but it does have implications for trade.
In Canada, CWD is a "federally reportable disease." This means that producers or veterinarians must notify the Canadian Food Inspection Agency (CFIA) of all suspected cases.
Animals with CWD may show a number of different signs as the disease progresses. These include the following:
- lack of coordination
- separation from the other animals in the herd
- excess salivation
- unusual behaviour
- weight loss
- difficulty swallowing
- increased thirst and urination
These signs can typically last for weeks or months before the animal dies; however, some animals may not show clinical signs. While animals are usually three to four years old before clinical signs appear, clinical signs have been seen in animals as young as 15 months or as old as 13 years.
If you are enrolled in a Canadian CWD Herd Certification Program
For more information on Canada's compartment of cervids that are low risk for CWD infection, see Herd Certification. If the herd where the confirmed positive animal (index animal) is identified is enrolled in a Herd Certification Program (CWD-HCP) and compliant at level D or higher, that herd will be eligible for the CFIA CWD compartment (full) disease response:
- legal restrictions on the premises (such as quarantine and Declaration of Infected Place)
- destruction and disposal
- compensation (if eligible)
- ordering decontamination and
- tracing to ascertain the source of infection and identify any other CWD-HCP herds at risk within the compartment
If an owner of a CWD-positive herd is enrolled in a CWD-HCP, they have the option to request opting out of the CFIA's CWD-HCP disease response before a Declaration of Infected Place is issued. If approved, the herd will then be treated similarly to a CWD-positive herd that is not enrolled in a CWD-HCP. If the owner does not opt out, the CFIA will proceed with the CWD compartment response in order to protect the compartment.
Disease response elements
All of the following disease response elements apply to CWD-HCP-enrolled herds compliant at level D or higher that are thereby eligible for the CFIA's CWD-HCP disease response.
For CWD-positive herds that are not in a CWD-HCP or are not compliant to level D, the CFIA will conduct an initial disease response including movement controls, trace-ins and trace-outs.
When CWD is diagnosed on any premises, a legal movement control (such as a quarantine) is applied to all cervids, cervid products and things that have been exposed to CWD. As a result, no cervids, cervid products or things may enter or leave the property without written CFIA approval. This is done to limit the spread of disease while the disease investigation is taking place.
An "index premises" is the first premises where CWD is identified in a disease investigation. If a CWD-HCP herd owner does not opt out of the CWD-HCP disease response, a Declaration of Infected Place will be placed on this premises. Any other premises where a cervid from this herd has resided in the last 18 months of its life could also be considered a CWD-positive premise and will be investigated accordingly.
Infected premises could also be any premises where a CWD- positive animal has resided during its life. There is a risk that CWD may spread from the premises and that animals or things entering the premises could become affected or contaminated. For all CWD-positive CWD-HCP premises that have not opted out of the CWD-HCP disease response, the CFIA will assess the level of environmental contamination and classify the premises as having either a low or high risk for potential for contamination with CWD.
Destruction and disposal
In CWD-positive CWD-HCP herds at level D or higher and herds that were exposed to the index animal in the previous 18 months (herds of residence), all CWD-exposed cervids will be destroyed and all cervids animals over 12 months of age will be tested for CWD. Destruction may occur on farm or, in the case of elk and red deer over 12 months of age, at an abattoir where full ante-mortem and post-mortem inspections are carried out.
Elk and red deer over 12 months of age that are slaughtered and test negative for CWD may be released for human consumption. Disposal options for other animals that are ordered destroyed are as follows: burial, incineration, or via commercial specified risk material (SRM) channels.
Owners will be eligible for compensation for every cervid ordered destroyed on a premises.
Cleaning and disinfection
All positive premises that undergo the CFIA CWD-HCP disease response will also be ordered to undergo cleaning and disinfection procedures that are specific to the premises. Cleaning and disinfection must be carried out to reduce the risk of environmental contamination with CWD prions as much as possible.
Trace-ins and trace-outs
Tracing of all movements in to and out of a CWD-positive herd will be used to establish controls over further spread of CWD to CWD-HCP herds, and thereby protect the integrity of Canada's compartment for CWD.
All CWD-positive premises are subject to an epidemiological investigation (including inventory and identification verification). Separate outcomes exist depending on whether or not the positive herd and/or the trace-in or trace-out herd are on a CWD-HCP, as well as what CWD-HCP level the herd in question has achieved. In all cases, the tracing period is 5 years before the date that the index animal (first case) was confirmed positive or the date of exposure of the herd to CWD.
Herds that are not eligible for the CFIA CWD compartment response (or that have opted out)
For herds that are not compliant with the HCP at level D or higher or that have opted out of a compartment response, the CFIA will only provide an initial (limited) disease response. The purpose of this limited response will be to determine whether any CWD HCP herds are at risk for CWD. The CFIA will:
- place movement controls on the positive premises (farm)
- conduct an epidemiological investigation and movement tracing to identify trace-in and trace-out herds
The CFIA will not:
- issue a Declaration of Infected Place
- provide destruction, disposal, cleaning or disinfection
- provide compensation
CFIA approval would be required to sell or transfer ownership of cervids and cervid products or by-products originating from the CWD positive herd.Provinces and territories may have their own disease control requirements and actions.
On premises that have been classified as low risk, owners may introduce new cervids once all positive and exposed cervids have been removed from a premises, cleaning and disinfection have been completed, and all legal restrictions (such as the quarantine and Declaration of Infected Place) have been lifted. For more information on the CWD-HCP, see herd certification.
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