Extreme biosecurity needed against African swine fever
This article is based on an African swine fever webinar presented in January 2023, copyrighted under the terms of an agreement between Informa Markets and the University of Minnesota. The individual speakers are solely responsible for their content and opinions.
Dr. Maria Celia Antognoli is a veterinarian and Swine Health Senior Staff Officer at USDA APHIS. She emphasized that keeping African swine fever (ASF) out of a country is critical, since once the disease enters the country the chances of controlling it are greatly reduced. Border biosecurity and bio containment are critical.
Careful screening of travelers in contact with susceptible swine is key as is preventing the entry of illegal products, Antognoli said.
Gordon Spronk, co-founder of Pipestone Veterinary Services in Minnesota, agreed with Antognoli, noting that keeping the ASF virus out of the country can’t be emphasized enough. The US swine industry benefits from the unique status of not having ASF, he added.
There are two key differences between the ASF virus and other viruses, Spronk remarked. One is that ASF survives in the wild pig population. Strict biosecurity is needed to keep wild hogs from infecting commercial swine premises.
Another key difference of this virus is that it survives in uncooked pig meat, he said. People can transport meat infected with the ASF virus for hundreds or thousands of kilometers, resulting in a huge distance leap by the virus, he added.
“Those are two distinct things that are different about this virus. So, prevention and biosecurity are the key,” Spronk said.
Lessons from China
Dr. Arkin Wu, Pipestone Nutrition and Riverstone Farms in China, said that the concept of biosecurity works for every single disease, but ASF is special, and biosecurity must be practiced in an “extreme manner, according to our experience.”
People and supplies are the most important disease routes to focus on. Wu explained that testing was done with employees that handled infected animals. Even when the employees took three showers, the virus could still be detected. Wu clarified that the viruses found after the showers weren’t live viruses, but that RNA or DNA was detected, he noted.
In China, every single item that goes onto a farm is disinfected, Wu said.
“Anything that goes into the farm can be a potential carrier of the virus; you have to disinfect in different ways to prevent it,” he added. “Research shows that the virus can survive and can transmit through the feed. We do have mitigations to protect that route."
There is much discussion about whether ASF can be transmitted through the air, Wu noted. Technically it's not an airborne virus, but the only farm that never got ASF in the past three years used air filters, he emphasized.
There is some evidence that ASF can transmit through dust or insects, he said, especially when the viral load in the environment is very high. “You have to think about ways to protect from airborne [transmission] too,” Wu added.
“When we talk about ASF … when you talk about biosecurity practices, you have to do it in an extreme way,” Wu concluded.
Spronk added “I would urge producers to have someone come to their farm and do an on-farm audit of their biosecurity measures with a simple checkup. Do they have interventions in place for every pathway that this virus and other viruses can be transmitted? I would urge on-farm audits … to see where there are gaps.” he said.