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African Swine Fever: What You Need to Know
One of the deadliest swine viruses on earth, African swine fever (ASF), has spread for the first time to the world’s largest pork producing country, China. The situation is changing rapidly, but here is what we know today about the situation.
Is it under control in China?
No. The virus is spreading rapidly and uncontrollably throughout China. The first case was reported on August 3, 2018. By September 10, there were at least 15 cases in six or more provinces. China is the world’s largest pork producer, with a sow base of about 40 million (the U.S. has about 6 million).
How did it get into China?
Likely through Russia. Early DNA sequence analysis indicates that the virus in China is the same virus that has been spreading through Russia. In 2007, ASF was introduced into the Caucasus region of Eurasia, including Russia, Lithuania, Poland, and Romania, where it has spread widely among wild boars and domesticated pigs. The virus can persist for long periods in uncooked pig products.
How is it controlled?
Extermination of infected herds. There is no vaccine or other treatment for ASF.
How does it spread?
The ASF virus is highly contagious. It is endemic in feral or wild pigs, and transmission cycles between these animals and Ornithodoros ticks can prevent eradication. The virus is very resistant to disinfection.
Could the virus spread in feed ingredients?
Yes. This is a key area of potential high risk of disease transport to U.S. swine herds. Feed ingredients can support viral survival after trans-Atlantic and trans-Pacific shipping to U.S. ports and on to locations that manufacture feed for swine. Get more information on how to minimize risk from feed ingredients at swinehealth.org/feed-ingredient-safety.
How do uninfected farms in China handle the spreading risk?
Lockdown. People movement between farms in China has stopped. Pig traffic has stopped in or out of the provinces. Breeding stock companies have stopped deliveries of boars and gilts to farms.
What are the disease signs?
The first sign of infection is often sudden death. Other symptoms include fever, anorexia, lethargy, and weakness. Redness and blotching of the skin may also be seen, especially on ears, tail, legs, and ham. Bloody diarrhea may occur, as well as abortions in pregnant sows.
Is there a risk to humans?
No. ASF cannot be transmitted to humans, so it is not a public health or food safety concern.
How deadly is it to pigs?
ASF virus isolates vary in virulence from highly pathogenic strains that cause near 100% mortality to low–virulence isolates that can be difficult to diagnose.
Could the U.S. benefit from the situation in China?
Possibly, as long as we don’t get ASF. China may need to import more pork.
If the virus got into the wild pig population of the U.S., what would happen?
It has the potential to spread everywhere and create significant mortality issues as well as cut off exports immediately. Total devastation.
How could the virus reach the U.S.?
There are several ways: international travelers with contaminated footwear/clothing or who are carrying infected meat products; importation of contaminated meat products; and importation of contaminated feed ingredients. The contaminated article would need to either come into contact with or be fed to susceptible pigs.
What can producers do to protect their herds?
Use extreme caution if you have visitors or workers from ASF-positive regions of the world. Require a five-day downtime before they arrive at your farm or feed mill. Workers can't bring meat from their home country into the U.S. Visit with your feed suppliers to discuss the origin of the feed ingredients they are using in your diets. Enroll in the Secure Pork Supply program at SecurePork.org.