Chinese scientists discover clues to swine fever virus

Chinese scientists have detailed the structure of the African swine fever virus, which causes a fatal and highly contagious pig disease that has decimated hog herds across the world.

The latest discovery will offer clues into how the virus attacks host cells while evading the immune system in infected pigs, and inform future research into developing an effective vaccine, scientists said on Friday.

The ball-shaped virus, first encountered in Kenya in the 1920s, has five layers that contain over 30,000 protein subunits, according to a research team formed by scientists from the Institute of Biophysics of the Chinese Academy of Sciences and the Harbin Veterinary Research Institute of the Chinese Academy of Agricultural Sciences.

At 260 to 300 nanometers in diameter, it is the largest virus ever discovered by Chinese scientists, equivalent to 140 times the size of the Zika virus and 760 times the size of the hepatitis A virus, according to Wang Xiangxi, one of the lead scientists behind the discovery.

To unravel its complex and giant structure, the research team devoted four months to collecting more than 100 terabytes of data using the cryo-electron microscopy technique that allows researchers to see molecules in detail, he said.

Rao Zihe, an academician of the CAS who also heads the research team, said the latest discovery is just an initial step in a long march to battle the disease as it continues to threaten the global pork industry.

"More research will be devoted to how the virus interacts with host cells and possible mutation routes," he said.

This year, 26 countries and regions have reported outbreaks of African swine fever, leading to heavy losses of pig herds in these regions, especially in China and Vietnam.

Since China, the world's largest pork producer, detected its first outbreak last August in the northeastern province of Liaoning, the country has reported 157 such cases as of Wednesday, according to the Ministry of Agriculture and Rural Affairs.

Chinese scientists have ramped up efforts to study the virus in order to produce a vaccine.

Bu Zhigao, head of the research institute, also participated in the research that unveils the virus structure. "Due to the lack of a precise understanding of the virus structure, the development of a vaccine targeting African swine fever was stuck in a murky stage," he said. "Only traditional techniques could be applied before."

"Now, we are able to glean some significant clues from the newly discovered virus structure, which are expected to spur the development of new vaccines and technologies that can help curb the disease spread," he said.

The research institute announced in May that it has successfully developed two possible vaccines for the African swine fever virus and proved their safety and adequate immunization effects.

Bu said on Friday that related vaccines are now awaiting approval for trials from authorities.