About a quarter of the global pig population is expected to die as a result of an epidemic of African swine fever (ASF), according to the intergovernmental organisation responsible for coordinating animal disease control.

In the last year the spread of the disease has taken policymakers by surprise, and has been particularly devastating in China – home to the world’s largest pig population. The disease is also established in other Asian countries such as Vietnam and South Korea, and continues to wreak havoc in eastern Europe, where the current outbreak began in 2014.

The severity of the crisis means that global pork prices are rising, spurred largely by the demand from China, where as many as 100m pigs have been lost since ASF broke out there last year. In recent months, China has been granting export approval to foreign meat plants and signing deals around the world at a dizzying rate. US pork sales to China have doubled, while European pork prices have reached a six-year high.

Dr Mark Schipp, vice-president of the World Organisation for Animal Health (OIE), told a press conference this week that ASF was “the biggest threat to any commercial livestock of our generation”. He claimed that the spread of the disease in the past year to countries including China, which has half the world’s pig population, had inflamed a worldwide crisis.

Schipp said veterinary scientists worldwide were trying to find a vaccine for the disease, but that it was a “complex challenge” because of the nature of the virus. While the disease does not spread to humans, it is virtually 100% fatal once embedded in pig populations.

ASF can be transmitted through direct contact with infected animals, such as wild boar, and via ticks. But the virus can also survive several months in processed meat, and several years in frozen carcasses, so meat products are a particular concern for cross-border transmission. In July meat containing the ASF virus was found in products seized by port authorities in Northern Ireland.

The outbreak in China has been particularly serious, with as many as 100m pigs lost already according to China’s official declared inventory, according to Adam Speck, a senior commodity analyst at IHS Markit’s Agribusiness Intelligence. Rabobank, a financial services company that specialises in food and agriculture, predicted that this year China would lose between 20% and 70% of its herd: potentially as many as 350m pigsl. Official figures state that over 1m pigs have been culled.

The virus has now been identified in 50 countries, including Poland, Russia, South Korea and the Philippines. So far, the furthest west the disease has been found in live animals is in Belgium among the wild boar population. A cull is now planned in the country.

Alistair Driver, editor of the UK’s Pig World, said: “There have been suggestions recently from the Chinese government and industry representatives that the Chinese pig herd is ‘bottoming out’ and that we could see a recovery to something like previous levels in 2020.

“However, most global analysts believe this is very optimistic and that, given the enormous losses so far and the continued spread of the virus across China and other Asian countries, there will be a huge deficit in pork production for the foreseeable future. The Asian ASF crisis is having an enormous impact on the global pork industry, with record export volumes pushing prices up around the world.”