ASF Spreads Destruction, Dismay

Monday, November 21, 2022

Canada working feverishly to keep it out

By Geoff Geddes

While the pork sector has clearly had its fill of African swine fever (ASF), the feeling is far from mutual. As a double-barreled threat that is both deadly and contagious for pigs (yet no threat to humans or food safety), ASF now affects all areas of China, as well as sub-Saharan Africa, Mongolia, Vietnam, and parts of the European Union.

Though China made some progress against the disease, a recent recurrence in the Xinjiang Uygur Autonomous Region of the country, coupled with the expansion of ASF to other nations closer to home, has Canada on high alert.

"Put simply, ASF is a devastating disease because it's fatal and reportable," says Cam Dahl, general manager of Manitoba Pork.

Too close for comfort

Since first emerging in 2019, ASF has been a chief cause of concern for the pork sector. That worry was amplified recently as the disease appeared in Germany and France, as well as two countries in North America that are popular with tourists: Dominican Republic and Haiti.

From the outset, Canada has led the way in terms of ASF prevention and mitigation, and it seeks to go even farther in the face of a growing threat.

"When you see dogs at the airport, they aren't just looking for drugs," says Dahl. "They are also sniffing out illegal meat products that could transmit ASF or foot-and-mouth disease."

In large part, success with prevention hinges on close cooperation between industry and government at all levels.

"Pilots on incoming flights to Canada often reinforce that passengers may not bring pork into the country," says Trevor Sears, president and CEO of Canada Pork in Ottawa, Ontario. "As well, if we can leave imported feed ingredients like nutrients or micro-vitamins sitting for 60 or even 90 days before using them, it will reduce the viral load."

Fighting it full-bore

Canada is also taking its cue from developments in Europe, where the disease entered countries like Germany through wild pigs or boars.

"We must attend to invasive swine within our borders and seek to eradicate wild pigs not natural to Canada," says Dahl.

"Also, the first appearance of ASF in Europe was often in herds of four or six pigs, so we need to ensure that farms of all sizes understand the key principles of biosecurity and why they are so important."

As with many disease threats, experts say the critical chokepoint is ground zero: on the farm.

"Producers tire of hearing it, and we tire of saying it, but biosecurity is key," says Dr. Egan Brockhoff, veterinary counsellor for the Canadian Pork Council (CPC). "Make sure there are no opportunities for the virus to arrive and infect your pigs, and have a biosecurity plan to deal with wild pigs. We also have a number of great training videos on the CPC website that can serve as training resources for your team."

Though prevention is preferred, it's equally vital that Canada is prepped for a worst-case scenario.

"Our agency is coordinating efforts across the country to mitigate the impact of ASF," says Dr. Aruna Ambagala, head research scientist of the Mammalian Diseases Unit for the Canadian Food Inspection Agency's (CFIA) National Centre for Foreign Animal Disease laboratory in Winnipeg, Manitoba. "In addition to border security and import restrictions from ASF-positive nations, we have increased our diagnostic ability regarding ASF at both the federal and provincial level."

Training of swine vets via online seminars so that they can quickly recognize the virus and react accordingly has been another piece of the puzzle for the CFIA.

A managed response

As Canada unites against a common foe, a prime vehicle for collaboration is the African swine fever Executive Management Board (ASF EMB). Consisting of federal, provincial, and territorial governments, as well as representatives from industry, the board is providing guidance around an effective response to ASF.

"If we should get ASF in Canada, what do we do to keep the sector functional?" asks Dr. Brockhoff. "The board recently released recommendations for filling gaps in ASF preparedness. Under an ASF coordinator, team members are working on a daily basis to enhance our readiness."

In 2020, Canada launched CanSpotASF, an early-detection pilot program to limit the spread of the virus and improve reaction time to ASF. As part of the program, risk-based surveillance is being tested in federal and provincial abattoirs across the country, and veterinary presence and sampling has increased at smaller hog farms.

Central to any response plan is a vital question affecting hog producers and industry stakeholders across the country: "How do we stay afloat if we can't do business abroad or south of the border?" If ASF is detected in Canada, its reportable status means the virus has serious implications for exports, and that's bad news for Canada when it ships the majority of its pigs to other countries.

"This disease would immediately close our borders," says Dahl. "Given that we export 70 per cent of our pigs from Canada, and 90 per cent from Manitoba, such a closure spells disaster for the industry."

In order to maintain some trading activity in the face of ASF, Canada has established zoning arrangements with a number of countries. Using a control zone method, the infected premise and close surrounding areas would be prohibited from trading, while those outside the zone could continue doing business with nations that are parties to the pacts.

"We don't import from countries with ASF unless we have a zoning agreement with them," says Sears. "At present, Canada has such deals with the United States and EU, and we recently signed agreements with Singapore and Vietnam. Negotiations are underway with other nations as well, and they are reciprocal, so we could still export to them in spite of ASF reaching our shores."

Research & resist

At the same time, scientists are working diligently on a few fronts to aid industry in the fight.

"ASF is not an easy virus to work with or to grow in the lab," says Dr. Ambagala. "Compared to other pig diseases, it is more complicated; therefore, we have fewer tools to employ in studying ASF."

Passive surveillance is critical for early detection of an ASF incursion. Since collecting individual blood samples from pigs can be a challenge, researchers are studying alternate sample types for ASF detection such as oral fluids, processing fluids and lymph nodes. They are also looking at portable assays (tests) for in-field detection.

"We don't have the time and resources to open up all pig carcasses to harvest spleen samples for ASF testing, but harvesting lymph nodes that are accessible through the skin from a dead pig is relatively simple and quick," says Dr. Ambagala.

As with COVID-19, a global effort is required to win the war on ASF, a fact not lost on the Canadian government and industry at large. As one of only seven labs worldwide to earn an ASF designation from the World Organization of Animal Health (WOAH, previously known as OIE), the CFIA is now sharing that expertise with other countries.

"We have a major role to play in controlling and limiting ASF spread in the Americas," says Dr. Ambagala. "Some of the technology we develop and evaluate might not be optimal for Canada, yet it could have a place in countries with limited resources.

We are working on multiple avenues to help other nations establish labs and diagnostics to detect ASF."

Taking their best shot

Another research priority is the quest for an effective ASF vaccine.

"At present, there is no global vaccine to control the disease," says Dr. Ambagala. "There is one vaccine that was developed by the USDA (United States Department of Agriculture) and is currently licensed for use in Vietnam. The vaccine is highly effective and safe based on the studies conducted in Vietnam."

The challenge with this vaccine is that scientists currently are not able to differentiate between vaccinated and infected animals, which limits its use to ASF-free countries. Additionally, that particular vaccine cannot be mass-produced. Despite these limitations, it is seen as the best option for a country such as Vietnam.

"Vietnam has lost a lot of pigs to ASF, and I really hope this vaccine will help them control the outbreaks in order to save their pig industry," says Dr. Ambagala.

Even if the Vietnam version is not the panacea sought by many, it underlines the promise of vaccines to help stem the ASF tide.

"Canada continues to contribute to the global effort around vaccines," says Dr. Brockhoff. "We have researchers actively targeting both vaccines and improved diagnostics. Even if we're not currently in a position to use vaccines for ASF, the work is important and could lead to breakthroughs down the road."

Moving forward, Canada is working on other fronts and doing its best to prepare for the worst. Between March 18 and June 16 of this year, the CFIA ran consultations seeking feedback from industry and other government organizations on the country's proposed national standards and framework for ASF compartments.

"The compartmentalization program would run alongside our zoning arrangements, so the two are complementary," says Dr. Brockhoff. "Zoning is a geographical arrangement, whereas compartmentalization is a management system that uses biosecurity and surveillance to ensure that all exported pigs are free of ASF."

According to the Government of Canada website, "the national standards and framework requirements will be reviewed at a minimum annually, or sooner as required, based on new scientific information, international guidelines, or by the consensus of a review panel."

ASF was also on the program at the annual Animal Health Canada (AHC) – previously known as the National Farmed Animal Health and Welfare Council – forum in Ottawa on Sept. 20 and 21. The AHC website described the event as "… a vibrant meeting place for stakeholders in Canada's animal health and welfare system. It provides an opportunity for all farmed animal stakeholders to collaborate in the work of animal health and welfare in Canada."

In a session which included the Canadian Animal Health Surveillance System (CAHSS) and the Animal Health Emergency Management (AHEM) project, experts were to discuss leveraging tools that are useful during "peace time" to address outbreaks like ASF.

They also covered optimizing tool selection and resource allocation in the face of an animal health emergency.

Of course, doing all the right things doesn't guarantee that ASF can be kept at bay; still, it is a pretty good start.

"Canada is well positioned as one of the most prepared countries in the world to battle ASF," says Sears. "You can never be 100 per cent ready, as factors could always arise that we don't foresee. Our goal is to give ourselves the best possible chance of defeating this virus, and we're well on our way to doing that." BP