A deadly and highly contagious virus is threatening pork production in China in the run-up to Chinese New Year, when demand for the country’s most commonly eaten meat is at its highest level.

Over the past three months, African swine fever has spread to 12 Chinese provinces, an area home to more than half the country’s pig population. The virus, passed through contaminated feed or exposure to infected animals, has a near-100% fatality rate and there is no vaccine.

On Monday, officials identified two new cases in the south, the first in that region. About 70,000 pigs have been culled so far to prevent the spread of the virus, according to the ministry of agriculture, and much of the country’s pig-producing provinces are on lockdown.

The agriculture ministry said on Wednesday that it would ban the feeding of kitchen waste to pigs after linking the practice to the majority of the early cases. Beijing has not yet said how the diseaseentered the country, but the ministry found 62% of the first 21 outbreaks were related to the feeding of kitchen waste, according to a statement published on its website.

What is African swine fever and how does it spread? Read more

China, where pork consumption has increased in tandem with the country’s economic rise, is home to half the world’s population of pigs. Pork accounts for two-thirds of China’s meat consumption and is considered such an important food staple that the government maintains a strategic pork reserve.

On Tuesday, the southern province of Guangdong banned transport of its live pigs after an outbreak was discovered in neighbouring Hunan province. In September, the ministry of agriculture banned inter-provincial transport of hogs in 10 provinces next to affected regions. Beijing has banned imports of the product from any affected areas of the country.

Chinese officials have been quick to report and act on outbreaks, and have advised residents that the virus poses no threat to humans. The true scale and risk of the virus’s spread is still unknown, according to a US Department of Agriculture report. The industry is still dominated by small producers and farms, where biosecurity measures are more lax and contagion is more likely.

Kitchen waste or swill is widely used in China to feed pigs, particularly by small farmers, as it is cheaper than manufactured pig feed. Regulations require the swill to be heated to a certain temperature before being consumed, but industry experts say this step is often skipped.

Tang Ke, an official at the ministry of agriculture, said last week that pig prices would likely rise before the Chinese New Year holiday in February, when families gather over large meals. China consumes about 55m tonnes of pork a year, with most of it sourced internally.

Consumers and pork suppliers may take another hit as pork products from the US are now subject to import tariffs in the US-China trade war. Analysts say China is likely to turn to the EU, Brazil and Canada.

The virus could also affect Chinese pork products globally. China is the world’s largest pork producer, home to about 700 million pigs – half the global population.

On Tuesday, Japan said it discovered pork sausage brought over from Beijing that had been contaminated with African swine fever. The virus can survive in frozen pork products for years.