ASF will never be eliminated in China, says swine consultant

African swine fever (ASF) is still a huge problem in China and will never be eliminated, says Michael Ellermann, a professional swine consultant with Danish company Aspire Agritech Consulting. Ellermann is based in China, where he works with clients on training, farm management, and new farm development. He spoke at the Carthage Spring Swine Symposium today.

Boots on the ground report

Here is a summary of the ASF situation in China as of January 2021. (The numbers are even worse today, says Ellermann.)

East China: Some areas seriously infected with about 50% lost. Some companies in Jiangsu province lost 70% to 100% of sows.

Northeast China: Large-scale farms in intensive breeding area were mainly infected, with about 8% of sows lost. Family farms were less affected.

North China: About 20% of sows infected, with 3% lost. Some farms have started to produce pigs with the virus.

Central China: Henan province seriously infected, with about 50% sows lost.

South China: Guangxi was seriously infected, with 10% of sows lost.

Southwest China: Sichuan province and Chongqing lost about 10% of sows. About 40% of finishers were affected.

Vaccine strains to blame

Most current ASF cases are caused by a vaccine strain virus. The wild strain is rarely detected. In 2019, producers tried to produce their own vaccines. About 20 were produced and all were abandoned in 2020. Labs have now adjusted to detect the vaccine strain virus. The vaccine strain causes the same number of problems as the wild strain, but less death.

More than 20 strains of ASF were found by December 2020, all gene mutations compared with the earliest strains. Most are lower virulent strains, including natural mutations and vaccine strains.

All the vaccines have failed, says Ellermann. The official word is it will be another two to three years before there will be a qualified vaccine. A vaccine is needed before pig production levels in China will reach pre-ASF levels, he says.

Test and remove

Tooth pulling, or test and remove, is still the main approach for most herds infected with vaccine strain. 1. Mass test pens and animals. 2. Analyze test results and ID positives. 3. Remove positive animals and pens, including neighbors. 4. Test and remove every two days until test day 1, 3, 5, and 7 are 100% negative.

Depopulation is used for wild strain infections or herds where tooth pulling was a failure.

Still profitable

Healthy pigs are selected for breeding if they test and retest with ASF antibody and antigen, says Ellermann. Biosecurity measures that have been implemented are vast and, to some extent, effective. Pig prices are so high in China, he says, that producers can make a profit weaning just two pigs a litter.

"China still has a long way to go before it has recovered from ASF," says Ellermann. "But never underestimate the Chinese swine industry. Their ability to handle and solve problems is remarkable."