When the PRRS virus broke out in a large swine farm in Western Himmerland, Denmark, the farm veterinarian proposed treatment by vaccination against a totally different virus, PCV2, to strengthen the immune defences of the pigs enabling them to fight the PRRS virus (PRRSV) themselves.
It is noteworthy to add that the farmer had not vaccinated against circovirus prior to these events.
What should have been the healthiest of healthy 7 kg weaners, swine producer Bob Pinstrup brought from an SPF high health declared breeder, proved to be a newly PRRSV contaminated sow farm. PRRSV spread amongst the piglets shortly after arrival at one of Bob’s three swine farms, and arose major issues in terms of meningitis, general un-thriftiness and increased mortality.
However, issues really built up when the breeder regained freedom of PRRSV, hence delivering negative piglets into Bob Pinstrup’s PRRSV positive farms. The now fully susceptible piglets were contaminated by PRRSV immediately after arrival and heavily diseased.
The specialised swine vet, Charlotte Johannessen, contracted to, amongst others, Bob Pinstrup’s farms, explains:
– When the pigs get infected by PRRSV, they become much more susceptible to PCV2 – and vice versa. More simultaneous viral infections affect the pigs with a mutually increased impact on the immune system and physiology that “one plus one makes three”. In the farms of Bob Pinstrup we experienced a rapid increase in health issues: a doubling in mortality and particularly gastric ulcers in finishers says Charlotte Johannessen, herd health specialised swine vet, LVK, Denmark.
Had to think out of the box
The PRRS disease problems had to go. As Bob Pindstrup was facing the substantial expenses total depop-repop in three farms to eradicate PRRSV, Charlotte Johannessen proposed an experimental action plan.
– We had to think out of the box, to get rid of the repeated outbreaks, causing the owner losses of millions of Danish Kroner. I proposed to vaccinate all pigs on the farms with the PCV2 vaccine, Circovac® of Ceva Animal Health. Once I used and have generated positive experiences on substantial improvement of the immune defenses of the vaccinated pigs. The idea was, that if the pigs were strong enough at the time of PRRSv infection, they could fight and rid the virus on their own, explains Charlotte Johannesen.
The treatment of the future
Despite a less than 50 percent success rate estimate of Charlotte Johannessen, Bob Pinstrup approved of the experiment. ALL pigs on-farm was vaccinated with Circovac®, as was every weekly batch of 500 piglets at arrival. The experiment became a success. A few months following initiation, all blood samples from the three farms tested negative for PRRS antibodies.
– We very quickly observed improvements of the first vaccinated pigs. That encouraged us to vaccinate all. The improvements appeared surprisingly fast – simply because the vaccine strengthened the immune defences of the pigs. I have never tried this kind of solution before, but as a veterinarian, I like the idea of work around the diseases, make the animals stronger so that they themselves can fight an infection instead of medical treatment. This solution did not contain even one gram of antimicrobial treatment. This is the future of disease management and prevention, says Charlotte Johannessen.