Of these, 15,000 died by virus. The other 5,000 were destroyed as a precaution.
"It started with some pigs a day, and then hundreds," said Sun, a pork farmer and agricultural trader from the province of Hebei, China. "Finally, 800 pigs will die in one day."
African swine fever (ASF) degrades China's pork industry, the largest in the world. Dutch bank Rabobank, lending to the global agricultural sector, estimates that the country's pig population may shrink by a third in 2019 – up to 200 million animals – through a combination of disease and culling.
To put it in context
The virus does not harm humans but is deadly in pigs – and, at this time, there is no cure or vaccine. Beginning in Africa, prevalence has been recorded in eastern Europe and Russia before it first appeared in China in August.
Since then it has spread to other Asian countries, including Vietnam and Cambodia.
In March, the Chinese government said there was a "good control" of the epidemic. At a press conference last month, Beijing said ASF did not spread soon enough.
According to the United Nations & # 39; Food and Agriculture Organization (FAO), China's central authorities have taken the proper steps to bring the virus under control.
"They have done everything they can to control the disease, they have a plan, they have a strategy, they respond diligently," said Vincent Martin, FAO representative in China.
But the size of the outbreak could be greater than estimates officials, as some farmers tell CNN that the disease is not always recognized in one place.  Sun said the preliminary trial by The provincial officials in his Hebei farm was negative for the ASF. However after he posted pictures of dead animals online, the Disease Prevention and Control Center of the country tried to identify them and confirmed that they were carrying the virus.
Also in Hebei, both peasants Zhang Haixia watched all his 600 pigs die. The official cause of death, told him, is a regular swine influenza.
"Local officials are afraid to be sure," he told CNN. "They threatened us that there would be consequences if we reported higher positions in the government, and they were afraid of losing jobs because of this."