China's pig farmers are learning to live with a weakening but still widespread African swine fever (ASF) virus. Chinese officials--who always prioritize China's image over everything else--have lost interest in ASF now that it is no longer a crisis. There are disagreements about the extent of African swine fever infections, but no one disputes that the disease is endemic in the country and has joined the cocktail of pathogens that circulate in China--the world's biggest pork producer...and the world's largest petri dish.
There has been controversy over the extent of Chinese ASF infections since March when two securities analysts warned that a survey questionnaire showed widespread infection in northern China. Other articles immediately tried to debunk the report by quoting one or two farm managers who told them infections had peaked in December-January but said their company's farms were no longer experiencing serious problems. The agriculture ministry warned against spreading false information about disease but had nothing else to say.
A compilation of on-the-ground surveys of the pig industry in four Chinese provinces last month by market analysts found that there had been a surge of African swine fever infections last winter concentrated in northern provinces like Henan, Shanxi, Hebei, and Shandong. These ASF outbreaks were nowhere near as widespread nor as deadly as the outbreaks during 2018-19, but the disease has not gone away. A piglet diarrhea virus (PEDv) that wreaked havoc in China during 2011 is an ongoing serious threat in northeastern provinces.
An April 10 report in Shanghai news outlet The Paper consulted a securities analyst and two company farm managers who agreed that there had been a surge of ASF infections during the winter months--mainly in the north--but the ASF virus is not as deadly as it was during 2018-19. Sows are affected the most by ASF, and one major company's manager said weaned pigs per sow and other productivity indicators were down in the first quarter. Chinese megafarms have kept operations going by using a targeted "tooth extraction" method that culls only the infected animals while leaving others in place instead of clearing out entire farms. However, "tooth extraction" doesn't work as well with the multiple strains of ASF now circulating in northern provinces, because some can spread asymptomatically through the herd undetected.
A manager from a major company said there had been strange alterations of the virus since October 2021. His company had found high virus loads in pigs with mild symptoms, situations where positive test results were found 15-25 days after clearing out farms, and instances where testing flipped back and forth between positive and negative for no apparent reason.
Last week, a farm in Zhejiang Province told The Paper that their farm currently has no ASF infections, but farm managers remain vigilant against the disease since routine testing shows the virus is present in the surrounding environment, posing a constant risk for the farm. A Fujian province company farm manager told a similar story in the April 10 article.
An official in charge of livestock and veterinary affairs at China's agriculture ministry told The Paper ASF preventive measures have become a normal part of farm management, stabilizing the disease. The official reported that recent testing showed a positivity rate of about 0.02%, about the same as last year. (Back in 2020, the ministry reported a positivity rate of 4.94% but that was based on only 243 samples.) The official acknowledged that the positive rate for ASF goes up in the winter and varies by region. Another official in charge of pig industry monitoring admitted that their data is based on small samples that are not necessarily representative and sample does not include newly added production capacity (read "big company-run farms"), so data might not reflect the actual situation.
A theme of the articles is that biosecurity measures to prevent ASF have become commonplace on Chinese pig farms. However, the livestock and veterinary official warned farms not to cut back on biosecurity measures when farms are losing money. A securities analyst told The Paper that air scrubbers and ventilation systems are costly, and some farms are holding back on installing the most advanced equipment due to the expense. In Heilongjiang, the diarrhea virus is believed to spread through ventilation systems in barns due to poor biosecurity.
Farmers in Sichuan, Hebei, and Heilongjiang Provinces who used to raise hundreds or thousands of pigs told The Paper they had quit raising pigs because it was no longer profitable. One cited high biosecurity costs as a problem. An influx of corporate farms has boosted Sichuan's pork supply, driven out the region's backyard farmers and improved biosecurity. In northeastern provinces the number of small and medium farms has shrunk by half and most who remain specialize in "2nd fattening", a low-risk phase of pig-raising.
Chinese officials have not reported any ASF cases to the World Organization for Animal Health in more than a year. Pig news sites report about ASF cases in wild boar and small farms in Poland and South Africa, but no news of ASF in China except the March report and its later debunking. Obviously, that doesn't mean ASF has gone away. More likely, it means Chinese officials are no longer being pressured from above to give ASF full attention so they have slacked off.
The Zhejiang farm manager indicated that Government officials have relaxed their pressure and reduced disease reporting since pork supplies are plentiful now and pork is cheap. A company in Heilongjiang said that it is taking longer to get compensation from the government for pigs killed by ASF and the amount is less.
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