There is a 20% chance of African swine fever reaching the UK's pig population, according to a new document published by Defra.
The UK risk assessment, written in November 2018, was released in the public domain earlier this month.
The document calculates the risk of introducing African swine fever (ASF) to the UK pig population from EU member states.
In it, officials highlight how the risk level for ASF entry into the UK has been increased to 'medium'.
The cost of an outbreak in the UK could be around £45 million, but could go even further to as high as £70 million, Defra officials estimated.
An outbreak reaching 30 farms would be a “reasonable worst-case scenario”.
Despite the disease being fatal to pigs, it presents no risk to humans. There is no effective treatment or vaccine.
The document reads: “We consider there is an overall medium annual probability of introduction of ASF into the UK pig population considering all the pathways. From a management perspective, this is considered 'likely'”
Importing live pigs is not the only pathway for disease incursion, the document says. Disease can also be spread by sharing animal and feed transport vehicles and from contact between one farm and another or with feral pigs.
ASF around the world
The assessment comes as the disease was found in the Belgian region of Luxembourg in September 2018.
The Belgian government has since released €1m (£880m) for the culling of more than 4,000 commercial and domestic pigs in the infected zone.
Elsewhere, China has culled almost a million pigs as numerous outbreaks grip the country's $128 billion pork industry.
China is a major pig producing country and accounts for approximately half the global population of swine, estimated at 500 million.
Meanwhile, in an attempt to minimise disease risk in the UK, the government's Chief Veterinary Officer has warned haulier organisations, including the Road Haulage Association and the Freight Transport Association, of potential disease risks.
Christine Middlemiss stressed the need for everyone travelling between the continent and the UK, including all types of hauliers, to take “several precautions to reduce the risk of ASF entering the UK”.
In the UK, the pig population consists of around 4 million animals in commercial pig farms, not including non-assured or small holdings or backyard pigs.
The feral pig population is several hundreds in isolated populations, the largest of which is the Forest of Dean.