Veterinary View: Why we must do everything in our powers to avoid importing pig diseases

In the latest issue of Pig World, LYSAN EPPINK, president of the Pig Veterinary Society and Boehringer Ingelheim Animal Health UK and ROI’s swine veterinary adviser, explains why the industry needs to take all precautions possible to keep disease out of the country. 

In this world with lots of international trade, it’s never been more important to stop new diseases coming into the country. 

There are some simple steps pig keepers can take to minimise the risk of introducing novel diseases or strains when importing pigs or semen. If we look specifically at PRRS (the pig disease focus of the Animal Health and Welfare Pathway), the UK is only positive for PRRS virus type 1 (PRRSv-1) strain. 

This causes, in the UK at least, a relatively mild disease compared to the type 2 strain, which can cause abortion levels up to 50%. 

However, PRRSv-2 is present in many other countries, so we need to be careful not to bring that one in. 

Possibly, of even more concern are the highly pathogenic PRRSv-1 strains that are also circulating in some countries; the Rosalia strain in Spain is a terrifying example of what a PRRSv-1 strain can do – losses of up to and over 40% have been reported. 

So while the UK is positive for type 1, this is one PRRSv-1 strain you do not want to give to your pigs.

Because the risks of introducing something novel can be minimised by doing some checks and tests prior to importation as well as after arrival, PVS has been working with the NPA and APHA’s Pig Expert Group on the current NPA import protocol, which is part of the Red Tractor standard. 

The protocol includes checking, not only the herd status for certain diseases –you must only import from herds that are free of these specified diseases – but also the vaccination status for PRRS, ensuring there is no vaccination in the source herd. 

The latter is important since some herds thought to be free of PRRS are vaccinated against PRRS as an insurance policy. PRRS vaccines are mostly modified live vaccines (and in many countries, both type 1 and type 2 strains are licensed), and, as such, the vaccine strain can spread to other susceptible pigs, including via semen. This shedding can last for several months, even when the virus has been cleared from the blood (the most common sample type used for PRRS testing). 

By following the NPA protocol, which includes isolation and testing pre- and post-import, the risk of missing a pig, or semen, that carries the PRRS virus, or other diseases tested for, is near enough eliminated. 

However, it is vital to follow the isolation protocols properly; it would not be the first time something has been picked up in isolation and subsequently dealt with to prevent spread. Taking a short cut at this last hurdle puts the whole herd at risk, so do it right to protect all your pigs. 

As always when dealing with the health of your pigs, ask your vet for advice and to discuss the health and test results with the vet of the source herd prior to purchase.