Porcine Epidemic Diarrhoea Virus (PEDv)

Porcine Epidemic Diarrhoea Virus (PEDv) has hit the pig industry in North America over the past year. This serious disease epidemic causes severe diarrhoea in all ages of pigs and high death rates amongst piglets.

The disease first arose in Asia and the USA, with most states in the USA witnessing outbreaks and has since occurred in Canada and Mexico. The source of the virus has not been determined, nor how it has spread so rapidly across such a wide geographic area. As a result, all countries including Britain are on high alert in case the disease makes a presence.

The new strain of PEDv is highly infectious and moves very easily between pig units not only by infected animals but anything which may be contaminated with the virus. With a milder form of PEDv seen in Wales in previous years, the industry is naïve to this virulent virus which will cause serious infection if introduced to Wales.

The Animal and Plant Health Agency (APHA) continues to monitor the situation in Europe to help minimise the risk of the disease entering the UK.

PED was made a notifiable disease in England in December 2015, albeit with significant differences from traditional notifiable diseases of pigs. Unlike other notifiable diseases, there is no legislative requirement for official testing, culling, movement controls or other restrictions.

The pig sector in Wales is very different to the structure of the pig industry in England that has large numbers of pigs located in regions close to European transport routes. Therefore, whilst PED is not notifiable in Wales, pig keepers play an important role in preventing PED outbreaks reaching Wales and in controlling their spread.

Pig keepers are therefore being encouraged to take measures now to minimise the risk of PED and other diseases being introduced to their premises and to their pigs.

What is PEDv?

Porcine Epidemic Diarrhoea Virus (PEDv) is caused by a coronavirus which damages the villi in the small intestine of the pig. This affects absorption in the gut, resulting in dehydration and severe diarrhoea. It is highly infectious and causes significant morbidity and mortality in piglets.

In older pigs the virus is less damaging and pigs usually get sick and lose weight after being infected. For newborn piglets, the lack of maternal protection against the disease means that they are particularly susceptible and diarrhoea often leads to dehydration and death.

As a result, PEDv presents a huge financial burden to affected pig herds.

A milder strain of PEDv has been circulating Europe since the 1970s and is present in some UK pig populations in low levels. Both viruses cannot be transmitted to humans nor contaminate the human food supply chain.

Symptoms to watch out for:

The diarrhoea is watery and may be seen in all age groups of pigs.
An outbreak of rapidly spreading diarrhoea, with reduced appetite, lethargy, dehydration and vomiting.
High mortality (up to 100%) in litters of piglets caused by dehydration. High mortality in sucking pigs would be an early sign of virulent PEDv but the diarrhoea may resemble other causes of enteric disease in older pigs.
On outdoor/ straw based units piglets can be found dead before diarrhoea is detected.
Mortality rates decrease as age of the pig increases, with infected finishers/ sows recovering quickly. Diarrhoea due to virulent PEDv in weaned and older pigs is transient and pigs recover, but intercurrent infections such as salmonellosis could mean that more prolonged diarrhoea or deaths are seen in growing pigs.

Preventing the spread of PEDv infection

The main source of PEDv is infected faeces. Anything that is contaminated with even a tiny amount of infected pig faeces can be a source of infection for other pigs including:

Pigs, people, vehicles, other animal vectors (including rodents, birds, foxes, flies, pets and other farm livestock), equipment and via contaminated bedding, feed and water
PEDv can also be spread through the air, via semen and porcine blood plasma.

If you don’t have PEDv, focus on keeping it out

General biosecurity principles should be followed to minimise disease risk
Restrict visitor entry
Use barriers to limit access to pig areas of the farm/premises – fences and gates, no entry signs. A line of separation is a good way to differentiate between the farm facilities, its animals and staff from lorries, trailers and people who must remain outside of the pig production area. This could include hauliers, feed deliveries, contractors removing manure etc.
Be clear about what you expect from visiting vehicles and people
Effective cleaning and disinfection can inactivate and destroy pathogens from any potentially contaminated surfaces. Remove organic matter with suitable detergent at the correct concentration, wash thoroughly and then give surfaces time to dry.
Source incoming pigs and supplies carefully
Manage wildlife access.

What to do if you suspect PEDv on your farm:

Contact your veterinary practice and report the suspicion as soon as possible.

Apply biosecurity measures immediately to prevent the virus from spreading via pig movements, vehicles, footwear etc. Pigs should not be moved before the unit is given the all clear.

There is no vaccine for PEDv, once disease has entered a pig unit preventing the effects of the disease is limited to controlled exposure with pregnant sows (to allow maternal antibody production) and good management to prevent dehydration.

The best way to beat PEDv is to contain it on infected farms and prevent it from spreading across the industry. The key to success is early detection and isolating the infection – please follow this guidance to help the industry avoid devastating losses should PEDv occur in Wales/ Britain.

PEDv Contingency Plan

The Pig Health and Welfare Council have published a contingency plan for dealing with PEDv. This is a living document which will evolve and develop over time. The contingency plan looks to identify, contain and eliminate any new highly virulent strains of the virus in Britain as quickly as possible.

For more information on PEDv, the contingency plan and biosecurity measures please use the following links:

http://www.bpex.org.uk/health-welfare/health/emerging-diseases/pedv/

http://www.npa-uk.org.uk/Pages/Biosecurity/PED%202013.html