If a test for PED proves positive, Government action will be limited to informing industry, so tracings can be carried out and improved biosecurity measures put in place.

The measure has been introduced by Government at the request of pig industry bodies, including NPA, because PED remains a significant threat to British pig-keepers.

Outbreaks of high-impact strains caused up to 100 percent mortality in young pigs in the United States, knocking out around 10 percent of pig production in 2013-2014, and the disease has since spread to Ukraine. Even with milder European Union strains, piglet mortality as high as 70 percent has been reported.

NPA is calling the new measure "lightweight" notifiable because unlike with other notifiable diseases there will be no statutory movement controls, no compulsory slaughter and no blocks on exports.

This is similar to the consensual Canadian model for combatting the disease, which has proved effective.

Under the new legislation, Apha will be legally permitted to confidentially inform AHDB Pork — the agreed "appropriate organisation" — of suspect and confirmed cases.

AHDB Pork will then use its best judgement to provide biosecurity guidance to the pig unit concerned. It will also carry out tracings and alert at-risk contacts as necessary.

The aim will be to prevent spread of PED and to eliminate the disease from the pig unit. There will be no requirement to slaughter affected animals.

PED has been made lightweight notifiable following an informal consultation process with the pig industry. NPA and others called for the measure so an outbreak can be identified as quickly as possible, spread can be prevented, and the disease can be eliminated from the unit concerned.

"The industry's method of tackling the disease and ensuring it doesn't spread will be to introduce a raft of biosecurity measures," said NPA chief executive Dr Zoe Davies.

"It worked in Canada and we are confident it will work here — as long as it is identified at the earliest possible stage."

PED, which is harmless to humans, is a coronavirus that infects the cells lining the small intestine of a pig, causing severe diarrhoea and dehydration. The disease is most serious in new-born suckling piglets where it can cause high levels of mortality. In older pigs, the disease often leads to loss of production.

The main source of PED is infected faeces.

As all commercial pig producers are aware, it can be spread by pigs, people, vehicles, equipment, contaminated bedding, feed and waste, and animal vectors, including rodents, birds, foxes, flies, pets and other farm livestock.

The tiniest amount of infected pig faeces — a thimbleful is often quoted — can be a source of infection for other pigs. Spread can only be controlled by introducing scrupulous biosecurity measures.

Pig Veterinary Society vets are familiar with the clinical signs of PED, and will help inform their general practitioner colleagues.

Diarrhoea spreads rapidly in a group of pigs over a few days. The disease can affect any age of pig but typically causes 30-100 percent in young piglets. The diarrhoea tends to be watery. Diarrhoea in older pigs is transient and they recover. Sometimes pigs also show reduced appetite and lethargy and may vomit.