African swine fever (ASF) - fact sheet
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About African swine fever
African swine fever (ASF) is a serious viral disease of pigs that can cause fever, internal bleeding and high death rates. It is highly contagious and can spread rapidly through both direct and indirect contact with infected pigs or pig products.
African swine fever only affects members of the pig family.
Risks to human health
No. There is no evidence that the ASF virus can infect humans, and it is not considered a food safety risk.
The clinical signs of ASF
The clinical signs of ASF range from mild to severe and may appear suddenly or cause chronic illness. The disease looks very similar to classical swine fever.
ASF virus can cause the following symptoms:
- high fever
- loss of appetite
- inability to stand
- reddening of the skin
- internal bleeding
- vomiting and diarrhea (sometimes bloody)
- abortions in pregnant sows
- death may occur suddenly or following a period of illness
Death rates and the degree of illness vary with the strain of the virus. Severe strains of ASF kill almost 100 percent of infected pigs. Other strains of the virus will cause milder clinical signs, such as slight fever, reduced appetite and depression, and may be confused with other diseases.
Chronic infections are rarely seen in outbreak situations but, when they occur, clinical signs include extreme weight loss, pneumonia, enlarged lymph nodes, skin ulcers and arthritis.
African wild swine (warthogs and bush pigs) do not usually show signs of illness when they are infected and, therefore, they act as carriers of the virus.
Areas affected by ASF
ASF is routinely found in several African countries. Since 2007, the disease has spread across several countries in central Asia, including China for the first time in 2018, as well as several European countries. Distribution among countries changes, depending on new infections, re-infections and the success of eradication programs.
ASF has never been found in Canada.
The transmission and spread of ASF
ASF can be spread directly between sick and healthy pigs. This happens through contact with the blood, tissues, secretions and excretions from infected pigs. Animals that recover may become persistent carriers of the virus. Their role in the spread of the disease is not fully understood.
The virus also persists in the body tissues after death. The virus can survive for several months in fresh pork and processed pork products, which can be a risk for transmitting disease. 1 of the most common ways ASF is spread from country to country is through people feeding pigs uncooked food scraps that are infected with the virus. The virus is not a human food safety risk.
African swine fever can also be spread indirectly. Because the ASF virus can survive for long periods of time outside of the host, it can be spread by contamination of objects, such as:
- farm equipment
- clothing and footwear
- livestock feed
Soft ticks have been shown to carry the virus. In Africa, they are considered to be the primary mode of transmission, particularly between the native wild hogs and domesticated animals. It is not known if the tick species found in Canada are capable of transmitting ASF.
ASF should be suspected based on clinical signs along with a high death rate in the herd. Pig owners should report suspicious deaths to their veterinarian.
Laboratory tests performed in a Canadian Food Inspection Agency (CFIA) or another approved lab are necessary to confirm the disease.
There is no treatment or vaccine for ASF.
Protecting pigs that are part of a small hobby farm from contracting ASF
Everyone has a role to play in reducing the risks associated with animal diseases including ASF.
On-farm biosecurity is critical, including for small hobby farmers and producers, to preventing diseases from developing and spreading. Careful sourcing of animals, products and by-products, including feed and feed ingredients, is important.
It is illegal to feed meat to pigs under of the CFIA's Heath of Animals Regulations; this includes all pet foods that contain meat or meat by-products and food waste containing meat. Producers, including small scale pig farm owners, are reminded that it is illegal to feed pigs international waste (leftover food garbage from ships or airplanes) because contaminated food and garbage can introduce and/or spread ASF and other highly contagious swine diseases to Canada. In general, producers should be cautious when feeding pigs any waste/kitchen food scraps. In the rare event that an item of food has even a trace amount of the virus, it could infect pigs if fed to them (although harmless to humans).
Also, prevent any contact between your animals as well as people working on your farm with wild swine; wild swine can be carriers of the disease and can pose a serious threat to your animals. Transmission can occur through nose to nose contact and through contamination of fields, pastures, feed and feed ingredients and water sources from the urine, feces and saliva of wild pigs. Clothing, boots and equipment used by people who were in contact with infected wild swine also pose a risk. It should be noted that at the present time, ASF has not been detected in Canada's wild swine population.
If you have anyone visiting or working on your farm that may have visited a country that is currently infected with ASF, be sure to follow strict biosecurity measures prior to that individual coming back onto your premises, including prohibiting them from coming onto your farm for 14 days. For guidance on disease prevention on farm, you should consult the Canadian Swine Health Board's National Swine Farm-Level Biosecurity Standard.
Disease prevention and control
The main pathways in which ASF can be introduced into North America
There are 5 main risk pathways:
- Lack of strong on-farm biosecurity standards - ASF can be brought onto a farm by people who have visited farms from areas that are affected with ASF. This includes bringing contaminated food, clothing or equipment onto farms
- International travellers - People, such as farm workers, foreign exchange students or hunters, who travelled to countries affected with ASF, could bring back contaminated food, clothing or equipment
- Small scale producers and pig pet owners - ASF can survive for several months in fresh, frozen, cooked, partially cooked and processed pork products. Feeding pigs food scraps that are infected with the virus can spread the disease to their animals
- Animal feed - ASF can be spread through contaminated feed or feed ingredients
- Contact with wild pigs - ASF can be spread directly between sick and healthy pigs. This happens through contact with the blood, tissues, secretions and excretions from infected pigs
Work being done to protect Canadian livestock from an outbreak of ASF
The Canadian Food Inspection Agency (CFIA) imposes strict regulations on the import of animals, germplasms and animal products from countries that Canada does not officially recognize free from ASF. These regulations are enforced through point-of-entry inspections by the Canada Border Services Agency or the CFIA.
Everyone has a role to play in reducing the risks associated with animal diseases.
- On-farm biosecurity is key to helping prevent diseases from developing and spreading. Careful sourcing of animals, products and by-products, including feed and feed ingredients is important
- For guidance on disease prevention on farm, swine producers should consult the Canadian Swine Health Board's National Swine Farm-Level Biosecurity Standard
- Producers are reminded that it is illegal to feed pigs international waste (leftover food garbage from ships or airplanes) because contaminated food and garbage can spread ASF and other highly contagious swine diseases into Canada. It is also illegal to feed meat to pigs
- In general, producers should be cautious when feeding pigs any waste/kitchen food scraps. Although harmless to humans, in the rare event that an item of food had even a trace amount of the virus, it could infect pigs if fed to them
- Travellers are reminded to declare all animal and food products at the border to prevent the spread of disease and to take precautions when visiting farms and travelling to infected areas
ASF is a reportable disease under the Reportable Diseases Regulations, and all cases must be reported immediately to the Canadian Food Inspection Agency (CFIA).
Proactive measures the CFIA is taking to help reduce the risk of ASF being introduced in Canada
To prevent the introduction of swine diseases of concern, including ASF, into the country, Canada has had rigorous import restrictions in place for live swine, and swine related products and by-products for some time. In addition, the CFIA is monitoring the global situation and is taking a proactive and collaborative approach to prevent ASF from being introduced to Canada. We have initiated additional preparedness planning through a National Response team. This team is dedicated to ensuring appropriate laboratory and field response capacity are maintained in Canada.
As part of its ongoing proactive measures, the CFIA has/is:
- import restrictions and border control of products brought in by international travellers in place to minimize the chances of introducing the virus into Canada
- liaising and coordinating communications efforts with federal, provincial and international partners stakeholders, including Agriculture Canada, Canada Border Services Agency (CBSA), provincial governments and Chief Veterinary Officers, industry and the United States Department of Agriculture (USDA)
- working with industry experts to ensure adequate supports are in place for all aspects of a disease outbreak scenario
- assessing the imports conditions based on ongoing risk assessment of countries from which Canada imports
- working with the European Union to monitor the situation in affected countries and updating import controls as needed
- establishing harmonized diagnostic testing for ASF with Australia, New Zealand, the US and Mexico
- encouraging enhanced biosecurity measures including recommendations for travellers
CFIA personnel trained in identifying signs of ASF in swine herds
We are committed to preparing the organization, in the event we do need to respond to an outbreak – having the necessary resources in place and ensuring our people have the adequate training they need are among the key components necessary in managing and eradicating the disease.
This includes training and refresher practice for front line staff in areas such as disease recognition, initial investigation and sampling techniques on swine.
Measures being taken to raise awareness among producers about the risks and prevention of ASF and the CFIA's role in this
The CFIA, in collaboration with industry and provincial and territorial authorities, are providing information on effective biosecurity measures, and making producers aware of how to recognize the signs of ASF.
Travellers can help reduce the risks of ASF being introduced into Canada
Travellers are reminded to declare all animal and food products at the border to prevent the spread of foreign animal diseases such as African swine fever (ASF). Also, pork or pork by-products from ASF affected countries, regardless of whether it is fresh, frozen, processed or cooked, is also not allowed to be brought into the country.
Travellers are also reminded to take additional precautions when visiting farms while travelling to and from infected areas, including washing all clothing and footwear worn while travelling to a country that is infected with ASF prior to re-entering Canada.
If you have visited a farm or animals, it is crucial that you declare your visit upon re-entry into Canada, Also, if while travelling you had contact with wild boars, postpone any pig farm visits in Canada for at least 14 days.
The CFIA has the capability to conduct all the necessary testing, should ASF be introduced to Canada
CFIA has complete diagnostic capabilities for ASF. In addition they are working with National Laboratories in Australia, New Zealand the United States and Mexico to harmonize and advance diagnostic capacity between laboratories from the 5 countries.
The transmission of ASF through animal feed
African swine fever (ASF) and other foreign animal diseases (FAD) can be transmitted via contaminated feed or feed ingredients imported from countries where these diseases are present.
Pig owners can reduce the risks of their feed being contaminated with ASF
Holding feed ingredients in storage prior to feeding can reduce viral survival. Time, temperature, the feed ingredient itself, and the properties of the virus all impact survival time. All 4 of these factors are critical but a simple rule is the higher the temperature, the shorter the virus survival time.
The Canadian Pork Council (CPC) recommends holding feed ingredients at a temperature of 20 degrees Celsius for 20 days or 10 degrees Celsius for 100 days.
Other considerations pig owners should keep in mind are:
- the country of origin for feed ingredients
- ask your Feed Mills and Feed Ingredient Suppliers to select sources that are from countries free of Foreign Animal Disease when possible, or at a minimum, are compliant with known quality assurance standardization
- select Feed Mills that are part of a recognized biosecurity program and participate in the Animal Nutrition Association of Canada's Feed Assure Program and follow their National Biosecurity Guide
Advice for producers when feeding their herd swill feed
Producers can feed their pigs non-meat food scraps although caution should be used.
Producers, including small scale pig farm owners, are reminded that it is illegal to feed pigs international waste (leftover food garbage from ships or airplanes) because contaminated food and garbage can spread ASF and other highly contagious swine diseases into Canada. It is illegal to feed meat to pigs under of the CFIA's Heath of Animals Regulations; this includes all pet foods that contain meat or meat by-products and food waste containing meat.
In general, producers should be cautious when feeding pigs any waste/kitchen food scraps. Although harmless to humans, in the rare event that an item of food had even a trace amount of the virus, it could infect pigs if fed to them.
The CFIA evaluates the safety of pet food imports
The CFIA uses risk assessments to determine if a hazard is present in a country and to evaluate the risk of transmission of that hazard resulting from the importation of animals, animal products, or by-products including pet food.
Multiple factors and diseases play a role in developing the import conditions that are necessary to provide an appropriate level of protection for public and animal health. Import conditions are established following country evaluations and hazard identification for the particular animal or commodity to be imported. For commodities that do not have previously established import conditions, a risk assessment is conducted to evaluate whether the commodity could be imported.
The CFIA also recognizes specific countries, or part of a country, as being free of, or as posing a negligible risk for, a particular disease. This recognition of freedom from a particular disease depends on various factors that include the CFIA having assessed the country as possessing an equivalent veterinary infrastructure to Canada's.
Countries that have not been evaluated by the CFIA are not considered as being free of diseases of concern like African swine fever (ASF). These countries require a case-by-case evaluation of the import of pet food containing ingredients of animal origin. Animal health requirements are needed such as heat treatments and handling of the finished product to mitigate the risk for introduction of foreign diseases in line with Canadian regulations and international guidelines and recommendations.
Import and export
Canada's requirements on importing pork products from any of the countries that have confirmed cases of ASF and the measures taken to ensure that imports of pork and pork by-products are safe
Canada does not import pigs (or their semen or embryos) or pork by-products that originate from any countries or regions that are not officially recognized as ASF free.
ASF affected countries that have been evaluated and approved by the CFIA such as certain countries within the European Union, may export:
- Products that contain pork ingredients that have gone through a thermal heat treatment process to eliminate the risk of introducing the ASF virus; and
- Fresh and frozen pork from regions within an affected country are recognized as ASF free
The only products that are allowed to be imported into Canada from ASF infected areas in certain parts of Asia must come from establishments that have been audited and approved by the CFIA. These products are:
- Chinese dumplings that are produced in CFIA approved plants that do not use pork originating from China, and the pork comes from CFIA approved countries
- Chicken jerky or compound pet chews and treats; and
- Pet chews and treats made with solely dried raw hide may be imported from any country if it meets the CFIA's import requirements, including heat treatment and cross-contamination prevention measures
Eligibility of of imports to Canada of pork and pork by-products from particular countries
Canada has not banned any products that were previously eligible for import. Pork and pork by-products have never been eligible for import from any country or region affected by a serious animal disease, such as African swine fever. Canada only imports pigs or pork by-products that originate from countries or regions that are officially recognized as free of African swine fever or any other serious swine disease.
Given the large number of hogs that cross the Canada/US border, Canada is coordinating ASF disease control measures with the US
CFIA is in regular contact with USDA APHIS about the current ASF situation. CFIA is coordinating several ASF preparedness and response related activities with USDA. Canada is also looking into the possibility of creating a joint ASF working group with the US and Mexico.
Canada exporting pork products to countries currently affected with ASF
Canada is free from ASF and has stringent import controls in place to maintain this status which enables Canada to export to international markets with confidence and to maintain the trust of our trading partners.
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