Researchers at the Swine Disease Eradication Center, University of Minnesota College of Veterinary Medicine in the US tested ultraviolet light as a means to inactivate the PRRS virus. And yes, it seems to work!
It is known that ultraviolet light neutralizes viruses, bacteria and parasites by disrupting the nucleic acid and preventing further replication. In this respect, UV light is considered quite advantageous over other virus inactivating procedures such as solvent detergent and pasteurization which have limited efficacy against, non-enveloped or heat stable viruses.
Different materials tested
A study was conducted to assess the effect of UV(254) on the concentration and viability of PRRSV on surfaces and materials commonly encountered on swine farms. A standard quantity (5×10(6)TCID(50), total dose) of a PRRSV modified live vaccine virus was inoculated onto 2 matched sets of surfaces/materials including wood, plastic, latex, rubber, styrofoam, metal, leather, cloth, concrete, cardboard, glass and paper. One set was exposed to UV(254) radiation (treatments) and the other to incandescent light (controls) for a 24h period. During this time, treatments and controls were swabbed at 10min intervals from 0 to 60min post-inoculation (PI) and again at 24h PI.
The quantity of PRRSV RNA on each item at each sampling time was calculated by RT-PCR and the presence of viable PRRSV in each sample was determined by swine bioassay.
Less harboured viable virus
A significant reduction (p<0.0001) in the quantity of PRRSV RNA was demonstrated at 24h PI independent of treatment. In addition, a significant reduction (p=0.012) in the number of UV(254)-treated surfaces which harboured viable virus was observed at 60min (0/12 positive) when compared to control surfaces (5/12 positive). In addition, all UV(254) treated samples collected between 10 and 50min PI were bioassay negative.
The researchers suggest that UV(254) is an effective means to inactivate PRRSV on commonly encountered farm surfaces and materials and inactivation can be accomplished following 10min of exposure.