PRRS eradication on a newly infected 3000 sow farm using MLV and KV

A 3000 sow SPF GGP farm was infected by PRRS virus in August 2014 with severe clinical signs. The eradication process has started in 3 months.

The eradication has been done by herd closure on the sow farm and partial depopulation on the rearing farm. Strong internal biosecurity measures were introduced on the farm. The farm started 3-week batch system to help clear the virus from the farrowing rooms and to make AIAO in the nursery by building. The herd has been vaccinated by MLV (Unistrain) 2 times on weeks 40 and 44 in 2014. The piglets before weaning (at 3 weeks of age) have been monitored by PCR (180 samples/batch) pooled by 5) form the beginning of 2015. At the first sampling, we have checked the serology titers too. The third of the 3-week-old piglets were seronegative on the 1st week of January, so an inactivated vaccination (Progressis) has been implemented 3 weeks prior farrowing to raise the maternal immunity. In late April more than 90% of the weaned piglets were PCR positive without any clinical signs, so in May, we made a mass vaccination again by MLV (Unistrain).

The KV significantly increased the maternal antibody titers. The first negative batch has been weaned at the end of June 2015 and so far all the batches are negative. In the rearing facilities all the piglets are negative till the end by now.

The eradication is possible by herd closure, even on a large farm using MLV for the mass infection.

The KV is a good tool to raise the maternal immunity after MLV vaccination.

Even a large farm can be managed by 3-week batch system.

Disclosure of Interest: None Declared.