A new form of African swine fever identified in Chinese pig farms is more likely to be caused by illegal vaccines, business owners say, a new blow to the world’s largest pig producer, yet recovery from epilepsy of the virus.
Two new strains of African swine fever have caught more than 1,000 sows on several farms owned by New Hope Liuhe, China’s fourth-largest producer, as well as fattening pigs for the company by contract farmers, said Yan Zhichun, the company’s chief science officer. .
While the rays, which are missing one or two key genes present in the African wild swine fever virus, will not kill pigs as the disease that devastated Chinese farms in 2018 and 2019, they are causing a persistent condition that reduces the number of healthy pigs. born, Yan told Reuters. At New Hope, and many major producers, infected pigs are culled to prevent the spread, making the disease effectively deadly.
Although the known diseases are now limited, if the rays spread widely, they could cut pig production in the world’s leading consumer and producer; two years ago, swine fever killed half of China ‘s 400 million pig herd. Pig prices remain at record highs and China is under pressure to strengthen food security amid the COVID-19 pandemic.
“I don’t know where they come from, but we found some mild field diseases caused by some kind of genetically extracted viruses,” Yan said.
Wayne Johnson, a Beijing-based veterinarian, said he was diagnosed with a form of the disease, or less deadly, in pigs last year. The virus, known as the MGF360 gene, did not have some genetic components. New Hope has found strains of the virus that are missing on both the MGF360 genes and the CD2v genes, Yan said.
Research has shown that deleting some MGF360 genes from African swine fever creates immunity. But the modified virus was not developed into a vaccine because it tended to revert to a harmful state.
“You can sort these things, don’t delete those duplicates, and if it’s exactly as described in the lab, it’s too much of a coincidence, because you wouldn’t get that exact deletion, ”Said Lucilla Steinaa, chief scientist at Livestock International. Research Institute (ILRI) in Nairobi.
Vaccination is not allowed for African swine fever, which is not harmful to humans. But many Chinese farmers struggling to protect their pigs have resorted to unconventional results, industry insiders and experts said. They fear that illegal vaccines have created catastrophic diseases, which are now spreading.
The new rays could spread across the globe through contaminated meat, by introducing pigs that are fed on kitchen waste. The virus is known to live for months in some pig products.
China’s Ministry of Agriculture and Rural Affairs did not respond to two requests for comment.
But it has issued at least three warnings against the unauthorized use of African swine fever vaccines, warning that they could have serious side effects and that producers and consumers could be charged with a crime .
In August, the ministry said it would test pigs for different strains of the virus as part of a nationwide investigation into the use of illegal vaccines.
Any sequences with gene deletion could indicate that a vaccine has been used, he said. No results have been published so far on the issue, which is well known for Beijing. The recent events of African swine fever have been widely reported.
After decades of research into the release of a vaccine against the large, complex swine fever virus, researchers around the world are focusing on live virus vaccines – the same type who has shown no promise.
But that vaccine has higher risks because even after the virus has been weakened so that it does not cause a serious illness, it can sometimes catch up with the virus.
One such vaccine used in Spain in the 1960s caused chronic infection with swollen joints, skin lesions and respiratory issues in pigs that made complex efforts to eradicate African swine fever over the next three decades. . Since then, no country has approved a vaccine for the disease.
Vaccines with both the deleted MGF360 and CD2v genes are undergoing tests by the Harbin Medical Research Institute in China after they showed promise.
Yan said that he believes that the series of viruses being studied, which have been published in scientific literature, have been rewritten, and that pigs injected with illegal vaccines based on them could be engaging others.
“It’s definitely made by people; this is not a natural pressure,” he said.
Neither Johnson nor Yan have followed the new strains of swine fever. Beijing has strict control over who is allowed to work with the virus, which can only be treated in laboratories with high biosecurity specifications.
But several private companies have developed test devices that scan for specific genes.
GM Biotech, based in central China’s Hunan region, said in an online post last week that they had developed a test that identifies whether the pathogen is a viral strain, a strained snoring single-gene deleted, or strained snort deleted by double gene.
The test helps pig producers because the new rays are “very difficult to detect at the initial stage of the disease and have a longer incubation period after infection,” the company said.
The government has not said how widespread illegal vaccines are or who made them. However, a “huge number” of pigs in China have been vaccinated, Johnson said, a sentiment echoed by many other experts.
In 2004-5, as strains of H5 flu spread across Asia, Chinese laboratories administered several unlicensed avian flu vaccines, said Mo Salman, a professor of veterinary medicine at Colorado State University, who has been working on animal health in Asia. they fear they could produce dangerous new twists.
“The routine ASF illegal vaccine (s) in China are retelling history,” said Salman.